A Paleolimnological Assessment of Recent Environmental

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A PALEOLIMNOLOGICAL ASSESSMENT OF RECENT ENVIRONMENTAL

CHANGES IN LAKES OF THE WESTERN CANADIAN ARCTIC

Joshua Robert Thienpont

A thesis submitted to the Department of Biology

in conformity with the requirements for

the degree of Doctor of Philosophy

Queen’s University

Kingston, Ontario, Canada

(April, 2013)

The freshwater ecosystems in the western Canadian Arctic are threatened by multiple and

interacting stressors, as high-latitude regions are undergoing rapid change resulting from climate

warming and other human-related activities. However, due to the paucity or absence of

monitoring data, little is known about long-term changes in lake ecosystems. This thesis

addresses this knowledge gap by using paleolimnological techniques to assess the responses of freshwater ecosystems in the Mackenzie Delta region to three major stressors predicted to become increasingly important, namely impacts from accelerated permafrost thaw, marine storm surges, and hydrocarbon exploration. Using a paired-lake design, six reference lakes were compared to six lakes impacted by retrogressive thaw slumps, an important form of thermokarst in this region. While all of the study lakes have undergone ecologically significant biological changes over the last ~200 years as a result of warming, lakes impacted by thaw slumps have changed more due to the cumulative effects of warming and heightened permafrost thaw. In addition to warming, the outer Mackenzie Delta is a low-lying landscape that is susceptible to inundation by marine storm surges from the Beaufort Sea. A large storm event in 1999 flooded

>10,000 hectares of the outer delta. My paleolimnological data show that this marine intrusion resulted in diatom assemblage changes in flooded lakes on a landscape-scale that were unprecedented in the recent past, suggesting recent warming, and associated sea-ice decreases, are making this region more susceptible to storm-surge damage. Finally, lakes impacted by sumps used to dispose of the drilling by-products of hydrocarbon exploration exhibit distinct water chemistry, and are particularly elevated in potassium and chloride, which form a major component of some drilling fluids. Related to this, a discernible change in cladoceran assemblages coeval with the time of sump construction suggest that sump failure has resulted in

ii biological changes in affected lakes. Collectively, this research shows that the ecosystems of the western Canadian Arctic are under threat from multiple stressors that have resulted in changes to the chemistry and biology of the freshwater resources of this region.

iii

Co-Authorship

Chapter 2 was co-authored by Kathleen Rühland, Michael Pisaric, Steven Kokelj, Linda Kimpe, Jules Blais and John Smol and represents original work as part of my PhD thesis. I designed the project, conducted the field work, analyzed all diatom samples, conducted all statistical analyses and was the primary author on this paper. This chapter has been published separately. Thienpont J.R., Rühland, K.M., Pisaric, M.F.J., Kokelj, S.V., Kimpe, L.E., Blais, J.M., and Smol, J.P. 2013. Biological responses to permafrost thaw slumping in Canadian Arctic lakes. Freshwater Biology 58 (2): 337–353.

Chapter 3 was co-authored by Daniel Johnson, Holly Nesbitt, Steven Kokelj, Michael Pisaric, and John Smol and represents original work completed as part of my PhD thesis. I designed the research, conducted all field work, analyzed diatom samples from one lake, conducted all statistical analyses and was the primary author on this paper. This chapter has been published separately. Thienpont, J.R., Johnson, D., Nesbitt, H., Kokelj, S.V., Pisaric, M.F.J., and Smol, J.P. 2012. Arctic coastal freshwater ecosystem responses to a major saltwater intrusion: a landscape-scale palaeolimnological analysis. The Holocene 22 (12): 1447-1456.

Chapter 4 was co-authored by Steven Kokelj, Jennifer Korosi, Elisa Cheng, Cyndy Desjardins, Linda Kimpe, Jules Blais, Michael Pisaric and John Smol and represents original work as part of my PhD thesis. I designed the research, conducted all field work related to sediment core collection, analyzed the modern limnological data, analyzed all of the diatom samples and the cladoceran samples from one sediment core, conducted all statistical analyses and was the primary author on this paper. This chapter has been formatted for submission to Proceedings of the National Academy of Sciences (USA). Thienpont, J.R., Kokelj, S.V., Korosi, J.B., Cheng, E., Desjardins, C., Kimpe, L.E., Blais, J.M., Pisaric, M.F.J., and Smol, J.P. Exploratory hydrocarbon drilling impacts to Arctic lake ecosystems. In prep.

Appendix A was co-authored by Michael Pisaric, Steven Kokelj, Holly Nesbitt, Trevor Lantz, Steven Solomon (deceased), and John Smol. This chapter represents original work completed during the course of my PhD. I co-designed the research, conducted all field work related to lake sampling, analyzed diatom samples from the DZO-29 piston core, analyzed the paleolimnological data, and co-authored the manuscript. This chapter has been published separately. Pisaric, M.F.J.*, Thienpont, J.R.*, Kokelj, S.V., Nesbitt, H., Lantz, T.C., Solomon, S., and Smol, J.P. 2011. Impacts of a recent storm surge on an Arctic delta ecosystem examined in the context of the last millennium. Proceedings of the National Academy of Sciences (USA) 108 (22): 8960-8965. *Both authors contributed equally to the publication.

Acknowledgements

“The thing the ecologically illiterate don’t realize about an ecosystem is that it’s a system. A system! A system maintains a certain fluid stability that can be destroyed by a misstep in just one

niche. A system has order, a flowing from point to point. If something dams the flow, order

collapses. The untrained might miss that collapse until it was too late. That’s why the highest

function of ecology is the understanding of consequences.”

- Frank Herbert’s Dune

I first wish to acknowledge and thank John Smol, without whom this thesis would never have been possible. Thank you for taking a chance on a prospective 3rd year undergraduate summer student, undoubtedly just one application in a very large pile presented before you, as well as for the encouragement, mentorship and, equally importantly, laughs over the last several years. Thank you also to Mike Pisaric, Steve Kokelj and Kat Rühland for your assistance, knowledge and friendship throughout my degree, I could not have done it without your help. I would like to thank Jules Blais and Linda Kimpe for their assistance and guidance.

I would like to thank Brian Cumming and Melissa Lafrenière for providing feedback as members of my committee. To the members of the PEARL group, past and present, thank you for your friendship over the years. In particular, thank you to Adam Jeziorski, for holding the heavy bag when the only solution to a persistent scientific quandary was a good round of kick boxing.

To my parents and sister, thank you for your love and support. The gift of education is one of the most important parents can give their children, and I thank you for the many sacrifices

v you have made, without which I would not be where I am today. Thank you to all of my extended family, the Thienpont’s, Scott’s and Korosi’s, for your love and support. Finally, I end by thanking my wife Jenny Korosi. This process was so much more enjoyable because we undertook it together. Without your encouragement, love, advice and assistance this wouldn’t have been possible.

Table of Contents

Abstract ...... ii

Co-authorship ...... iv

Acknowledgements ...... v

List of Abbreviations ...... xii

List of Tables ...... xiii

List of Figures ...... xiv

Chapter 1: General introduction and literature review ...... 1

Thesis Objectives ...... 7

Literature Cited ...... 10

Chapter 2: Biological responses to permafrost thaw slumping in Canadian Arctic lakes . .14

Summary ...... 15

Introduction ...... 17

Methods ...... 21

Paired study design: site description ...... 22

Sediment core collection and diatom analyses ...... 24

Statistical analyses ...... 26

Results ...... 28

Discussion ...... 37

Regional climate warming ...... 37

Impacts of thaw slumping on diatom assemblage structure and lake habitat ...... 39

vii

Chemical changes due to slumping ...... 42

Acknowledgements ...... 45

References ...... 46

Supporting Information ...... 51

Chapter 3: Arctic coastal freshwater ecosystem responses to a major saltwater intrusion: a landscape-scale palaeolimnological analysis ...... 66

Abstract ...... 67

Introduction ...... 68

Methods ...... 70

Site description ...... 70

Lake sampling and sample preparation ...... 72

Geochronology and data analyses ...... 73

Results ...... 75

Relationships among limnological variables ...... 75

Diatom analyses ...... 75

Discussion ...... 81

Synchronous and unmatched impacts of the 1999 storm surge ...... 81

Assessing post-storm surge recovery ...... 85

Other diatom assemblage changes ...... 86

Conclusions ...... 88

Acknowledgements ...... 88

Funding ...... 89

viii

References ...... 89

Chapter 4: Exploratory hydrocarbon drilling impacts to Arctic lake ecosystems ...... 93

Abstract ...... 94

Introduction ...... 95

Results and Discussion ...... 99

Materials and Methods ...... 106

Acknowledgements ...... 107

References ...... 108

Supporting Information ...... 111

Chapter 5: General Discussion and Conclusions ...... 118

Future research ...... 123

Literature Cited ...... 125

Summary ...... 128

Appendix A: Impacts of a recent storm surge on an Arctic delta ecosystem examined in the context of the last millennium ...... 130

Abstract ...... 131

Introduction ...... 132

Results and Discussion ...... 133

Materials and Methods ...... 141

Acknowledgements ...... 142

Literature Cited ...... 143

Supporting Information ...... 145

Appendix B: Raw Count Data ...... 149

B.1: Lake INV07-2a – Raw Diatom Counts ...... 149

B.2: Lake INV07-2b – Raw Diatom Counts ...... 156

B.3: Lake INV07-4b – Raw Diatom Counts ...... 161

B.4: Lake INV07-5a – Raw Diatom Counts ...... 163

B.5: Lake INV07-5b – Raw Diatom Counts ...... 168

B.6: Lake INV08-6a – Raw Diatom Counts ...... 121

B.7: Lake INV08-6b – Raw Diatom Counts ...... 175

B.8: Lake INV08-7a – Raw Diatom Counts ...... 179

B.9: Lake INV07-7b – Raw Diatom Counts ...... 183

B.10: Lake INV08-9a – Raw Diatom Counts ...... 188

B.11: Lake INV08-9b – Raw Diatom Counts ...... 190

B.12: Lake INV08-14a – Raw Diatom Counts ...... 194

B.13: Lake INV08-14b – Raw Diatom Counts ...... 199

B.14: Lake INV08-36a – Raw Diatom Counts ...... 201

B.15: Lake INV08-36b – Raw Diatom Counts ...... 207

B.16: Lake INV09-I20 – Raw Diatom Counts ...... 209

B.17: Lake INV09-C23 – Raw Diatom Counts ...... 213

B.18: Lake INV10-C1A – Raw Diatom Counts ...... 215

B.19: Lake DZO–29–L1 – Raw Diatom Counts ...... 217

B.20: Lake T–34 – Raw Diatom Counts ...... 241

Appendix C: Currently accepted taxonomic name, most common synonym and / or basionym and taxonomic authority (for current name) for all diatom taxa encountered in the analysis of sediments from the Mackenzie Delta and delta uplands ...... 246

List of Abbreviations

ANOSIM – analysis of similarity ASE – accelerated solvent extraction asl – above sea level CONISS – constrained incremental sums of squares cluster analysis CRS – constant rate of supply DCA – detrended correspondence analysis DCCA – detrended canonical correspondence analysis DIC – dissolved inorganic carbon DOC – dissolved organic carbon DZO – dead zone PAH – polycyclic aromatic hydrocarbon PCA – principal components analysis SIMPER – similarity percentages TDS – total dissolved solids TDN – total dissolved nitrogen TP-F – total phosphorus (filtered / dissolved) TP-U – total phosphorus (unfiltered) VRS – visual reflectance spectroscopy Zmax – maximum lake depth

xii

List of Tables

Chapter 2:

Table 2.1: Select chemical variables for the 12 study lakes ...... 25

Table 2.2: Location and select physical variables for the 12 study lakes ...... 25

Table 2.3: Estimated timing of slump (re)initiation / acceleration based on air photo

evidence for the six slump-affected lakes analyzed ...... 28

Chapter 3:

Table 3.1: Select physical and chemical variables from the six study lakes from which

sediment cores were collected ...... 73

Table 3.2: Pearson correlation matrix for 13 storm surge impacted lakes from the outer

Mackenzie Delta sampled for water chemistry in August 2009...... 76

Chapter 4:

Table 4.S1: Summary statistics of water chemistry data for drilling sump lakes, thaw slump-

affected lakes and control lakes from the uplands east of the Mackenzie Delta, sampled in the

summers of 2005 and 2007 ...... 117

Appendix A:

Table A.S1: Environmental characteristics and water chemistry data for lakes in the study

area ...... 146

Table A.S2: Radiocarbon dates from the DZO-29 sediment core ...... 147

xiii

List of Figures

Chapter 2:

Figure 2.1: Map showing the location of the 12 study lakes in the Mackenzie Delta

uplands...... 19

Figure 2.2: Historic and reconstructed temperature record for the Inuvik region (NT,

Canada) ...... 23

Figure 2.3: Stratigraphic diatom profiles from each of the 12 lakes analysed, showing

recent assemblage shifts over the last c. 200 years...... 29-30

Figure 2.4: Summary of the relative abundance of all planktonic diatom taxa for a) the six

reference lakes, b) the six analyzed slump-affected lakes...... 31

Figure 2.5: Hill’s N2 diversity of the non-fragilarioid periphytic diatom assemblage for a)

the six reference lakes, and b) the six slump-affected lakes...... 31

Figure 2.6: Beta-diversity (SD units) determined before ⁄ after the timing of a priori defined

stressors...... 33

Figure 2.S1: Radioisotopic activity of 210Pb (circles), 226Ra (squares) and 137Cs (crosses)

for lakes 2a, 5a, 6a and 7a ...... 51

Figure 2.S2: Radioisotopic activity of 210Pb (circles), 226Ra (squares) and 137Cs (crosses)

for lakes 9a, 14a, 2b, and 5b ...... 52

Figure 2.S3: Radioisotopic activity of 210Pb (circles), 226Ra (squares) and 137Cs (crosses)

for lakes 6b, 7b, 9b, and 14b ...... 53

Figure 2.S4: Relative frequency diagrams of taxa >5% relative abundance for lakes 2a and

2b ...... 54

xiv

Figure 2.S5: Relative frequency diagrams of taxa > 5% relative abundance for lakes 5a and

5b ...... 55

Figure 2.S6: Relative frequency diagrams of taxa >5% relative abundance for lakes 6a and

6b ...... 56

Figure 2.S7: Relative frequency diagrams of taxa >5% relative abundance for lakes 7a and

7b ...... 57

Figure 2.S8: Relative frequency diagrams of taxa > 5% relative abundance for lakes 9a and

9b ...... 58

Figure 2.S9: Relative frequency diagrams of taxa > 5% relative abundance for lakes 14a

and 14b ...... 59

Chapter 3:

Figure 3.1: The location of the study area within the outer Mackenzie Delta, shown in the

context of Canada...... 71

Figure 3.2: A summary of the impact of the 1999 saltwater inundation on the water

chemistry and sedimentary diatom assemblages of 13 lakes from the outer Mackenzie

Delta ...... 77

Figure 3.3: Relative frequency diagrams of the diatom taxa found at greater than 5%

relative abundance from (a) impacted Lake DZO-2, (b) impacted Lake DZO-3, (c)

impacted lake DZO-30, (d) ‘transition’ lake T-34, (e) impacted Lake DZO-29 (Pisaric et

al., 2011) and (f) control Lake C-28 ...... 79

Figure 3.4: Diatom relative abundance PCA axis 1 and axis 2 sample scores for all six

study sites calculated and plotted in a single ordination space, and for each study lake

calculated individually ...... 82

Chapter 4:

Fig. 4.1. A) Location of the 101 study lakes in the Mackenzie Delta uplands (Northwest

Territories, Canada). B) Image of a failing drilling sump. C) Generalized schematic of a

drilling mud sump ...... 96

Figure 4.2: Principal components analysis (PCA) ordination of select chemical variables in the

101 lake dataset ...... 101

Figure 4.3: Stratigraphic profile of the most common cladoceran taxa for lakes A) I20,

impacted by drilling sump failure, and control lakes B) C23 and C) C1A ...... 105

Figure 4.4: Plot showing the changes in relative abundance of Alona circumfimbriata between

present-day (surface) and pre-industrial (bottom) sediment samples for 50 lakes in the

Canadian sub-Arctic ...... 105

Fig.4.S1. Boxplots of select environmental variables exhibiting significant differences

between the a priori defined groups ...... 115

Fig. 4.S2. Visual reflectance spectroscopically-inferred chlorophyll a (circles) and summed

12 priority polycyclic aromatic hydrocarbon concentrations (squares) for study lakes A)

I20, B) C23 and C) C1A ...... 116

Fig. 4.S3. Stratigraphic profile of the most common diatom taxa for lakes A) I20, impacted

by drilling sump failure, and control lakes B) C23 and C) C1A ...... 116

Appendix A:

xvi

Figure A.1: Study area and sites...... 134

Figure A.2: Alder shrub ring-width chronologies and mortality data ...... 136

Figure A.3: Stratigraphic profiles showing the relative abundances of the most common diatom taxa ...... 139

Figure A.S1: Specific conductivity (A) and soluble chloride concentrations (B) in active layer soils for impacted (n=66) and control sites (n=64) throughout the study area . . . . .145

Figure A.S2: Surface sediment core radioisotopic activity and core chronologies for DZO-

29 and C-28 ...... 146

xvii

Chapter 1

General Introduction and Literature Review

There is no longer any scientifically-credible doubt that the planet’s climate is changing.

Temperatures globally are rising because of the emission of greenhouse gases, which can be directly linked to human activities (IPCC 2007). Many high-latitude regions began experiencing this warming earlier than temperate regions (Douglas et al. 1994), and have undergone greater

warming to date than temperate regions (ACIA 2005; Prowse et al. 2009). In addition to

experiencing amplified, accelerated warming, many components of the Arctic system are being

affected by other aspects of a changing climate, such as changes in precipitation (Peterson et al.

2006), permafrost distribution (Nelson et al. 2002), sea-ice extent (Serreze et al. 2007),

vegetation communities (Tape et al. 2006), and the position of treeline (Devi et al. 2008). These

changes are resulting in greater biological change than in temperate locations (Root et al. 2003),

and are occurring in a landscape that is often considered more fragile than similar regions in the

south. Compounding these changes are stressors associated with increased human presence in the

north, an area long thought of as pristine, but under increasing pressure from direct

anthropogenic activities including human settlement, transportation and resource extraction

(Furgal and Prowse 2008). Freshwater ecosystems, one of the defining features of many northern

landscapes (Furgal and Prowse 2008), have already, and will continue to, experience climate-

related changes, and understanding the nature of these changes is essential.

Delta ecosystems are among the most lake-rich environments in the circumpolar north, and

are often thought to constitute biodiversity hotspots in the Arctic (Walker 1998). The largest

Arctic delta in North America, and second largest in the north only to the Lena River Delta is the

Mackenzie, in Canada’s western Arctic. The Mackenzie Delta provides many essential

1 ecosystem services, among them providing an important habitat for thousands of migratory water fowl, recognized through the establishment of the Kendall Island Migratory Bird Sanctuary in

1961 (Burn and Kokelj 2009). The Mackenzie Delta is also culturally important for the local indigenous communities in the region, the Inuvialuit and Gwich’in. As the western Canadian

Arctic is among the fastest warming regions on the planet (ACIA 2005), understanding the impact of climate change on the freshwater ecosystems of the region represents an important priority.

There are an estimated 25,000 lakes in the Mackenzie Delta itself (representing 15-50% of the surface area), with thousands more present in the surrounding uplands (Burn and Kokelj

2009). The delta is a Quaternary feature, formed from sediment deposited by the Mackenzie

River since the retreat of the Laurentide ice sheet, which occurred between 12.5 and 13 thousand years ago in the region (Duk-Rodkin and Lemmen 2000).The region occurs coincident with present-day treeline, transitioning from boreal forest composed of black and white spruce in the south, to the shrub tundra of the low sub-Arctic in the north (Ritchie 1994). The Delta is situated within the continuous permafrost zone, with thick permafrost (>800 m) present in the uplands bordering the delta, though discontinuous permafrost exists in some areas of the delta itself, due to the insulating effects of vegetation and water bodies (Burn 2002).

The western Canadian Arctic region has been warming since ~1900 (Szeicz and

MacDonald 1995), which is recorded by the instrumental records from the region (Lantz and

Kokelj 2008), and has warmed dramatically since ~1970, with the main warming trend occurring in the winter (Thienpont et al. Chapter 2, this volume). Associated with this regional temperature increase, permafrost ground temperatures have warmed over the last 40 years (Burn and Kokelj

2009). Because permafrost in the region is ice-rich, particularly in the uplands (Rampton 1988),

2 warming has the potential to result in significant thaw and associated subsidence (i.e. thermokarst; Kokelj et al. 2005).

Among the most dominant form of thermokarst in the region are shoreline retrogressive thaw slumps (Mackay 1963; Burn and Lewkowicz 1990), which currently occur on the margin of

~10% of the lakes greater than 1 ha in the Mackenzie Delta uplands, and have increased in average size and growth rate over the last 50 years, coincident with recent warming (Lantz and

Kokelj 2008). Surveys of modern limnological conditions have shown that retrogressive thaw slumps, which are expected to increase in frequency and magnitude as a result of increasing ground temperatures (Kokelj et al. 2009b),will affect the limnological properties of lakes in the

Mackenzie Delta uplands region (Kokelj et al. 2009a). For example, lakes impacted by thaw slump activity have been shown to have increased ionic concentrations and increased water clarity (lower dissolved organic carbon, DOC) (Kokelj et al. 2005, 2009a), lower nutrient levels

(Thompson 2009), and have a higher biomass of rooted aquatic macrophytes and mosses

(Mesquita et al. 2010) than nearby, undisturbed lakes. However, to date, little information on the biological response of lake ecosystems to thaw slump activity has been examined, despite the importance of this disturbance type in the region, particularly in the uplands surrounding the delta.

Due to the lack of relief in the low-lying outer Mackenzie Delta, large-scale geomorphic disturbances, such as retrogressive thaw slumps, are not common. This region, however, is threatened by inundation of saline marine waters into the generally freshwater lakes of the

Mackenzie Delta. The maximum elevation at the delta’s apex, Point Separation (~200 km south of the coast) is only approximately 15 m above mean sea level (Mackay 1963). As a result of this lack of relief, the outer delta region, much of which is only 1-2 m asl, is susceptible to inundation

by storm surges from the Beaufort Sea. Exacerbating this threat are recent declines in sea ice extent (Serreze et al. 2007) and land-fast ice (Dumas et al. 2006), features which have previously limited wind-induced wave energy transfer from large, late-season storms inland. This, coupled with the fact that the frequency and intensity of Arctic storms is increasing (ACIA 2005; Manson and Solomon 2007; Sepps and Jaagues 2011) and that sea levels are rising (Nicholls and

Cazenave 2010), has resulted in recent years producing some of the largest storms on record

(Manson and Solomon 2007). These storms have been shown to have resulted in major

ecological impacts to the freshwater ecosystems of the outer Mackenzie Delta (Pisaric et al.

2011; Deasley et al. 2012; Kokelj et al. 2012; Vermaire et al. 2013). However, despite these

initial studies, little is known about the historical record of possible impacts of any previous

storm surges on the lakes of the region.

Compounding the threat to the freshwater ecosystems of the delta region are potential

impacts from hydrocarbon exploration and extraction, which will likely increase as the demand

for these resources continues to increase, and warming of the region results in more economical

extraction and transportation to southern markets. The Mackenzie Delta and surrounding uplands

are underlain by significant discovered and expected hydrocarbon reserves, primarily natural gas

(Dixon et al. 1994). The development of these resources, as well as associated activities such as

the construction of the Mackenzie Gas Pipeline, which would run from the Mackenzie Delta

south to the Alberta border, has the potential to result in a variety of impacts to the sensitive

ecosystems of the region. To date, most development associated with hydrocarbon resources has

been in the form of exploratory drilling operations, with most activity occurring since the 1960s

(Jenkins et al. 2008). The primary disposal method of the wastes associated with exploratory

drilling operations is through the use of in-ground sumps, where drilling muds (composed of

drilling fluids, cuttings, rig wash, etc.) are disposed of in pits excavated into the permafrost,

allowed to freeze in situ, capped with the excavated over burden, and assumed to freeze, thus

representing a permanent disposal location for these wastes (Kokelj and GeoNorth 2002). Over

150 of these sumps have been constructed in the delta region since the 1960s (Jenkins et al.

2008). However, these sumps, previously thought to represent a permanent containment

mechanism for drilling fluids, many of which are toxic to aquatic organisms (Falk and Lawrence

1973; French 1980; Utz and Bohrer 2001), may be leaking. A study by Jenkins et al. (2008)

observed surficial and perimeter ponding at one third of the 110 drilling sumps examined in the

region, suggesting failure was occurring. Further analyses of these same sumps by Kanigan and

Kokelj (2010) showed that zones of high conductivity were observed outside the sump perimeter at 74% of the sites studied, though at half of these sites the loss of containment was < 30 m from the sump itself. Potassium chloride, one of the main constituents of drilling muds, has been shown to have migrated several hundred meters from failing drilling sumps (Dyke 2001). To date no information on the long-term impacts of exploratory drilling operations on the ecologically and culturally important freshwater resources of the region has been documented.

Permafrost thaw, marine storm surges, and other impacts from human development, including hydrocarbon exploration, as well as the general climate warming that is occurring in the region, have the potential to result in significant impacts to freshwater ecosystems in the

Mackenzie Delta and the surrounding uplands. However, one of the major problems associated with determining the impact of disturbances on these systems is a lack of long-term monitoring data (Smol 2008). For most regions, monitoring of even the most basic environmental variables does not extend beyond ~100-150 years, and in more remote locations records are of much shorter duration or entirely absent (Smol 2008). Air temperatures, arguably the most commonly

(and simplest) measured environmental variable, were first recorded in the Canadian Arctic at

Fort McPherson in 1892, with most locations only having temperature records extending back to

the mid-1900s (Historical Adjusted Climate Database of Canada). Many of these records also

include significant data gaps. Monitoring of limnological conditions in high-latitude regions is

almost entirely absent, and in the few cases where these records do exist, the monitoring post-

dates the onset of many environmental disturbances, such as climate warming. Indirect methods

are therefore required for inferring environmental conditions prior to the onset of ecosystem

disturbances where direct monitoring is absent. Paleoecological techniques, including the use of

the material preserved in lake sediment records, represent an essential set of tools for

understanding past changes to aquatic ecosystems, and have been widely used in Arctic regions

(Pienitz et al. 2008).

Paleolimnological techniques use the physical, chemical and biological information preserved in lake and river sediment records to reconstruct past limnological conditions (Smol

2008). Paleolimnological methods have been used to infer a wide variety of ecosystem changes in Arctic regions including cultural eutrophication (Michelutti et al. 2002), changes in ice cover

due to climate warming (Smol and Douglas 2007), and to track the sources and pathways of

atmospheric pollutants (Muir and Rose 2004). Among the most commonly used biological

indicator are the remains of diatom algae (division Bacillariophyta), due to the fact that their

siliceous cell walls are well preserved and taxonomically identifiable to the species or sub-

species level (Smol and Stoermer 2010). In addition, many diatom taxa have well-defined optima

and tolerances for a number of environmental variables (e.g. pH, TP, salinity), which makes them well-suited to reconstructing past limnological conditions (Smol 2008). Diatom-based

paleolimnological techniques from the western Canadian Arctic and sub-Arctic region have

focused on establishing baseline environmental conditions and developing diatom calibration

models (i.e. training sets), which can allow the quantitative reconstruction of certain limnological

conditions, including dissolved inorganic and dissolved organic carbon concentrations (Pienitz

and Smol 1993) as well as lake depth and surface-water temperature (Pienitz et al. 1995). In

addition, diatoms have been used for inferring the closure status of lakes in the Mackenzie Delta

itself (Hay et al. 1997, 2000; Michelutti et al. 2001). To date, however, no paleolimnological

investigations have been conducted to study the impacts of permafrost thaw, storm surge impacts

or hydrocarbon exploration on lake systems in this sensitive region. In this thesis I use primarily diatom-based techniques to assess the impact of these disturbances.

Thesis Objectives

The main objective of this PhD thesis is to assess the impacts of three major stressors on the freshwater ecosystems of the Mackenzie Delta region: permafrost thaw, storm surge impacts, and hydrocarbon exploration, as these stressors are predicted to become increasingly important in the future as climate warms and human impacts on the region increase. In total, this thesis consists of five chapters, including this introductory chapter, three data chapters, and a final discussion chapter. In chapter 2, my main research question is: How do shoreline retrogressive thaw slumps, a spectacular form of permafrost degradation, impact the biology of lakes in the

Mackenzie Delta uplands? This research builds on the foundational work of Kokelj et al. (2005) who established a unique paired-lake design to study the modern chemical differences in lakes impacted by thaw slumping, compared to undisturbed reference lakes. In this study I analyze lake sediment cores from 12 first-order lakes (6 slump-affected paired with 6 control sites) at relatively high-resolution, and use sedimentary diatom assemblages to infer how these lake

ecosystems change as a result of permafrost thaw. The use of sedimentary diatoms, which in

addition to being useful for tracking environmental changes such as permafrost thaw, has been

widely applied to inferring recent climate warming, will allow me to understand the cumulative

impacts of these two important stressors, intense, localized permafrost degradation and climate

change, on lakes in the Mackenzie Delta uplands. In order to quantitatively estimate the amount

of compositional change or “turnover” that has occurred related to these stressors (i.e. beta

diversity, scaled in SD units), direct ordination techniques (detrended canonical correspondence

analysis; DCCA) will be used.

In chapter 3 I answer the research questions: What is the ecological impact of saltwater

intrusion following marine storm surges on lakes spread across the outer Mackenzie Delta, and

how common have these events been in the recent past? The low-lying Mackenzie Delta is

susceptible to storm surge damages when marine waters from the Beaufort Sea are blown into

the generally freshwater delta system. A particularly large storm in September 1999 is known

from the instrumental and local indigenous knowledge record to have produced a large surge

event (Kokelj et al. 2012). Our preliminary research (Pisaric et al. 2011; included as Appendix A to this thesis) showed that at one lake system from the outer delta the storm surge resulted in a major shift from fresh to brackish conditions, and was unprecedented in the ~1000 year history of the lake ecosystem. To answer these questions, I will synthesize the modern water chemistry and analyze diatom-based sedimentary records from a series of impacted lakes from the outer delta region, in order to explore the spatial extent (if any) of the impact of the recent 1999 storm.

I will also be able to infer if any past storm surges resulted in ecological changes as observed in the biological sediment records of these sites. The results of this research have important

implications for ecosystem and human health, as most Arctic communities are coastal, and thus

are susceptible to storm-induced flooding.

Finally, in chapter 4 I examine the impact of exploratory drilling on the freshwater

ecosystems of the Mackenzie Delta uplands, an area underlain by significant hydrocarbon deposits, and the location of the proposed (and approved) Mackenzie Gas Pipeline. The primary mechanism for drilling fluid disposal is through the use of in-ground sumps, which were believed to constitute a permanent containment mechanism, however, recent evidence suggests many of these sumps are failing and thus drilling wastes may be leaking into nearby lakes. In chapter 4 I will answer two research questions. First, how does the modern chemistry of lakes impacted by drilling mud-sump failure compare to other lakes in the region? Second, what impact has sump failure had on the biology of impacted lakes, inferred from sedimentary remains? In order to put the current limnological conditions of sump-impacted lakes in the context of other lakes in the region I will compare the modern water chemistry of lakes in the vicinity of drilling sumps to reference lakes, and those impacted by permafrost thaw

(retrogressive thaw slumps, known to be highly disturbed systems). I will then analyze diatom and Cladocera remains in lake sediment cores from three sites (one drilling sump-impacted lake, and two control lakes), in order to assess whether these important indicator groups underwent changes at the approximate time of, or subsequent to, sump construction.

Collectively this thesis will help develop a greater understanding of the impacts of several important and emerging stressors on the freshwater ecosystems of the Mackenzie Delta region. This work emphasizes the importance of understanding how lakes have changed over time in order to better predict future responses to warming, and further highlights how

paleolimnological techniques can be used to track changes in ecosystems where no long-term

monitoring data are available.

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Chapter 2

Biological responses to permafrost thaw slumping in Arctic lakes

Summary

1. Rapid environmental change occurring in high-latitude regions has the potential to cause extensive thawing of permafrost. Retrogressive thaw slumps are a particularly spectacular form of permafrost degradation that can significantly impact lake–water chemistry; however, to date, the effects on aquatic biota have received little attention.

2. We used a diatom-based palaeolimnological approach featuring a paired lake study design to examine the impact of thaw slumping on freshwater ecosystems in the low Arctic of western

Canada. We compared biological responses in six lakes affected by permafrost degradation with six undisturbed, reference lakes.

3. Slump-affected lakes exhibited greater biological change than the paired reference systems, although all systems have undergone ecologically significant changes over the last 200 years.

Four of the six reference systems showed an increase in the relative abundance of planktonic algal taxa (diatoms and scaled chrysophytes), the earliest beginning about 1900, consistent with increased temperature trends in this region.

4. The response of sedimentary diatoms to thaw slumping was understandably variable, but primarily related to the intensity of disturbance and associated changes in aquatic habitat. Five of the slump-affected lakes recorded increases in the abundance and diversity of periphytic diatoms at the presumed time of slump initiation, consistent with increased water clarity and subsequent development of aquatic macrophyte communities. Slump-affected lakes generally displayed lower nutrient levels; however, in one system, thaw slumping, induced by an intense fire at the site in 1968, ostensibly led to pronounced nutrient enrichment that persists today.

5. Our results demonstrate that retrogressive thaw slumping represents an important stressor to the biological communities of lakes in the western Canadian Arctic and can result in a number of

15 limnological changes. We also show that palaeolimnological methods are effective for inferring the timing and response of aquatic ecosystems to permafrost degradation. These findings provide the first long-term perspective on the biological response to permafrost thaw, a stressor that will become increasingly important as northern landscapes respond to climate change.

Keywords: Arctic, climate change, diatoms, palaeolimnology, permafrost degradation

Introduction

Rapid environmental change due to climate warming is occurring across the planet, with high-latitude regions being particularly susceptible. Over the last century, the western Canadian

Arctic and Alaska have warmed by as much as 3–4 °C, with future temperature increases predicted to be far greater (Lantz & Kokelj, 2008; Prowse et al., 2009a). As a result of recent climate warming, impacts observed in high-latitude regions include increased precipitation

(Peterson et al., 2006), decreased sea ice extent (Serreze, Holland & Stroeve, 2007), increased shrub cover in tundra regions (Tape, Sturm & Racine, 2006; Lantz, Marsh & Kokelj, 2012), as well as northward shifts in the boundaries delineating permafrost zones (Nelson, Anisimov &

Shiklomanov, 2002). These changes correspond to observed increases in Northern Hemisphere temperatures over the last 50 years, which have been shown to be the largest in at least the last

1300 years (Jansen et al., 2007), though likely longer (Smol & Douglas, 2007a,b).

The response of high-latitude ecosystems to the degradation of permafrost as a result of rapid warming represents a key knowledge gap in our understanding of the consequences of climate change. It is widely accepted that permafrost is of critical importance for regulating global climate and carbon budgets (Dutta et al., 2006; Schuur et al., 2011), as well as in defining the local and regional hydrological and topographical nature of Arctic regions. Recent increases in permafrost temperatures have been observed across the circumpolar north (Smith et al., 2005;

Osterkamp, 2007; Romanovsky et al., 2007). The thawing of ice-rich permafrost across vast areas of the north will have major consequences at both local and global scales (Jorgenson, Shur

& Pullman, 2006; Lantz & Kokelj, 2008).

A major consequence of warming permafrost is an increase in thermokarst activity

(Jorgenson et al., 2006; Osterkamp, 2007), which results in terrain disturbance and significant

changes in soil and surface water chemistry (Kokelj & Burn, 2003). Retrogressive thaw slumps

are one of the most dramatic and widespread thermokarst forms in the western Arctic where they affect the catchments of up to 10% of the lakes in this water-rich landscape (Fig. 1) (Mackay,

1963; Lantz & Kokelj, 2008). These features consist of a headwall of exposed ground ice, a scar area and a debris flow (Burn & Lewkowicz, 1990). Headwall thawing and upslope growth of a thaw slump can progress for decades before stabilising, producing features that affect several hectares of terrain (Mackay, 1963; Burn & Lewkowicz, 1990). In the Mackenzie Delta region, a significant increase in the number and size of these lakeside thaw slumps has occurred since the

1970s in concert with an increase in mean annual air temperatures and rising permafrost

temperatures (Lantz & Kokelj, 2008; Burn & Kokelj, 2009). Kokelj et al. (2009a) demonstrated that warming permafrost can stimulate lateral talik growth, lake-bottom and shoreline subsidence and slump initiation, and thus, accelerated slumping can be anticipated to increase with further warming. It is predicted that accelerated thermokarst activity will be a significant stressor on the biota of Arctic aquatic ecosystems (Hobbie et al., 1999; Frey & McClelland, 2009), but there is limited information on the ecological response to this disturbance type.

In this study, we build on the research of Kokelj et al. (2005), Kokelj, Zajdlik &

Thompson (2009b) who established a paired lake design, from which the modern water chemistry of systems disturbed by retrogressive thaw slumps could be compared to otherwise similar (e.g. same geology, approximate size and location) reference systems. Studies have shown that permafrost soils can be geochemically and sedimentologically distinct from the active layer (Kokelj, Smith & Burn, 2002; Kokelj & Burn, 2005), and thus, thawing can release a variety of materials that can be transported to adjacent aquatic systems (Kokelj et al., 2005,

2009b). Lakes affected by thaw slumping have been shown to have comparably higher ionic

Fig. 1 Map showing the location of the 12 study lakes in the Mackenzie Delta uplands. Lakes classified as ‘a’ are reference systems, while ‘b’ lakes have shoreline retrogressive thaw slump activity on their margins. The inset map shows the location of the study area in the context of the Northwest Territories and Canada. Inset image (a) shows a typical reference site (Lake 9a). Inset image (b) shows a thaw slump-affected site (Lake 14b).

concentrations, lower dissolved organic carbon (DOC) concentrations and greater water

transparency (Thompson et al., 2008; Kokelj et al., 2009b). In impacted lakes, sediments are

lower in organic carbon and nitrogen and higher in calcium and magnesium, and are associated

with greater development of submerged macrophyte communities (Mesquita, Wrona & Prowse,

2010) and higher abundance of benthic invertebrates (Mesquita, Wrona & Prowse, 2008).

Nutrient concentrations, including total phosphorus (TP) and total dissolved nitrogen (TDN), as

well as water-column chlorophyll a concentrations, were found to be significantly lower in thaw

slump–impacted lakes than in reference sites (Thompson, 2009). Increasing active layer

thickness restricts thawing to the top-most layer of the permafrost and therefore cannot be responsible for the chemical changes observed in these lakes, as these soils are characterised by similar conditions as the active layer (Kokelj et al., 2002; Kokelj & Burn, 2005). Only intensive

geomorphic disturbance, such as thaw slumps, can result in the thaw of deeper solute-rich

permafrost (Kokelj et al., 2005). The intensity of slump impacts on lakes varies with age, activity

level and the size of the thaw slumps (Kokelj et al., 2009b). While this paired lake set has provided useful information on the contemporary differences between lakes affected by thaw slumps and reference systems, there are no pre-impact monitoring data with which to determine how a system changes when thaw slumping occurs. The examination of biological proxies preserved in the sediments of these paired lakes will provide an important opportunity to examine the longer-term changes and ecosystem trajectories in these freshwater systems as a

result of retrogressive thaw slumping and climate warming, as well as provide information on the

impact of thaw slumping on lake biota.

Palaeolimnology is effective for tracking environmental changes in remote regions where

direct monitoring is absent or postdates the onset of an environmental stressor (Pienitz, Douglas

& Smol, 2004; Smol, 2008), such as permafrost thaw. Diatoms (algae of the division

Bacillariophyta) are a commonly used palaeolimnological indicator, and previous investigations have used sedimentary diatoms to infer changes in lake–water chemistry, including salinity

(Wilson, Cumming & Smol, 1996), DOC and major ion-related variables such as dissolved inorganic carbon (DIC) (Rühland & Smol, 1998, 2002) and light conditions and aquatic habitat availability (Karst-Riddoch et al., 2005). In addition, a variety of climate-related lake properties, such as the length of the ice-free season, the onset, duration and strength of thermal stratification and the spring and autumn overturn, play important roles in algal community structure and seasonal dynamics. Diatoms have been found to respond to these changes (Smol & Douglas,

2007a; Rühland, Paterson & Smol, 2008) and can be used to assess whether recent temperature increases can be detected in the biological communities of all paired lakes.

Our objective in this study is to characterise the impact of retrogressive thaw slumping and the recent acceleration in thaw slump activity on the sedimentary diatom assemblages of a select subset of the same paired lakes that have been previously studied through comparative limnological approaches. Our overall goal is to provide the first long-term perspective on the impact of thermokarst processes on the biological responses of freshwater ecosystems. In addition to elucidating the impact of permafrost degradation on the primary producer communities of lakes in this sensitive region, sedimentary diatom changes may be useful for qualitatively inferring responses to the limnological conditions of the systems at the time of slump initiation. Ultimately, this may allow for the identification of a mechanism through which thaw slumping alters algal communities.

Methods

Paired study design: site description

This study focuses on assessing changes to lake systems in the western Canadian low

Arctic, near the Mackenzie Delta (Northwest Territories) (Fig. 1). The surficial geology of the region is composed of glaciogenic deposits hosting ice-rich (>80%) permafrost (Mackay, 1963;

Rampton, 1988). The region is characterised by thick, continuous permafrost >100 m thick

(Heginbottom, 2000). Thermokarst activity is well documented in the region, particularly

retrogressive thaw slumps (Mackay, 1963; Lantz & Kokelj, 2008). Our study region in the

Mackenzie Delta uplands lies within the ecotone between the boreal forest and the shrub tundra

of the low sub-Arctic (Lantz, Gergel & Kokelj, 2010).

Historical climate data recorded at Inuvik indicate temperatures have increased

substantially between 1926 and 2010 in all seasons (Fig. 2a), particularly in the past 45 years,

with the greatest increases recorded in winter (Fig. 2b). Dendrochronological reconstructions

from the region extend inferences of past climate farther back into time (Fig. 2c) and suggest that

unprecedented warming has been occurring since the early part of the 20th century (about 1910)

(Szeicz & MacDonald, 1995). Rapidly increasing air temperatures and ice-rich permafrost make

the Mackenzie Delta amongst the most thaw-sensitive permafrost regions of Canada (Kettles &

Tarnocai, 1999; Burn & Kokelj, 2009). Predicted air temperature increases for the region are

amongst the highest in Canada (Prowse et al., 2009b) and will undoubtedly be accompanied by

rising permafrost temperatures, deepening of the active layer and an increase in the magnitude

and frequency of thermokarst activity.

Twelve lakes (Fig. 1) with previously well-studied water chemistry (Kokelj et al., 2009b;

Table 1) were selected from the paired set of lake systems in the Mackenzie Delta uplands. Lake

pairs were selected to control for factors including lake size and morphometry, geographical

Fig. 2 (a) Mean annual and (b) mean winter composite temperature record for the Inuvik region (NT, Canada) since 1926 ⁄ 1927. Piecewise linear breakpoint analysis results are plotted. Vertical solid lines represent estimated breakpoints, with 95% confidence intervals plotted as vertical dashed lines. Based on linear equations before ⁄ after breakpoint, estimated temperature change over the given time period is included for each temperature record. Data from the Historical Adjusted Climate Database of Canada, Environment Canada (http://www.cccma.ec.gc.ca/hccd/). (c) Normalised dendrochronological reconstruction of June–July air temperature covering the period from 1750 to 1988 from the Mackenzie Mountains, including raw reconstruction (grey circles) and Loess-smoothed trend (black line), taken from Wilson et al. (2007), based on Szeicz & MacDonald (1995). Data from NOAA, National Climate Data Center.

location and surficial geology, with the only obvious difference being the presence or absence of

thaw slumping (Kokelj et al., 2005). These lakes range in depth from 2 to 11 m (Table 2). Lake

names follow the system established by Kokelj et al. (2005). Six lakes (those labelled ‘a’) having

no known history of permafrost degradation are considered to be ‘reference’ sites in this study

and will be contrasted with six lakes (labelled ‘b’) having visible thaw slump development on their margins and thus constituting the ‘slump-affected’ systems. Recent observational evidence suggests that one reference site, Lake 5a, may have a previously uncharacterised history of thaw

slumping, with small, well-vegetated ancient slump scars observed on its margin during field

sampling. Thaw slumping represents a large perturbation to these lake systems, with between 3 and 34% of the catchment having experienced slumping (Table 2).

Sediment core collection and diatom analyses

Sediment cores were collected from the centre (deepest location) of each lake over a 2- year period, in April 2007 and July 2008. Sediment cores were collected using a Glew-type

(1989) gravity corer (internal diameter 7.62 cm) and sectioned using a Glew (1988) vertical

extruder. Sediment age estimation was conducted using 210Pb and 137Cs radioisotopes following

standard methods for gamma dating (Schelske et al., 1994; Appleby, 2001). For all sediment cores, the constant rate of supply (CRS) model (Appleby & Oldfield, 1978) was used to calculate dates. Radioisotopic activity and age-depth model profiles, including uncertainty estimates for each lake, are included in Figs S1–S3 as supporting information.

Sedimentary siliceous subfossil analysis was carried out on selected intervals from each lake using standard methods for diatom sample preparation (Battarbee et al., 2001). For each interval, chrysophyte scales and stomatocysts were also enumerated, as the ratio of these

Table 1 Select chemical variables for the 12 study lakes

Table 2 Location and select physical variables for the 12 study lakes

siliceous indicators to the number of diatoms has been used previously to track a variety of

environmental changes (Smol, 1985; Cumming, Wilson & Smol, 1993; Douglas & Smol, 1995).

Statistical analyses

Instrumental climate data for Inuvik available from 1926 to 2010 (a lengthy record by

Canadian Arctic standards) were obtained from the Adjusted Historical Canadian Climate

Database. To identify a significant shift in the temperature trend, a piecewise linear regression

(Toms & Lesperance, 2003) was applied. Longer-term climate reconstructions (c. 1750–1988) based on dendrochronological analyses of samples taken from the Mackenzie Valley region were obtained from Wilson et al. (2007) based on the reconstruction of Szeicz & MacDonald (1995).

These data were obtained from the National Oceanic and Atmospheric Administration (NOAA)

National Climate Data Center.

Detrended canonical correspondence analysis (DCCA) was conducted for each lake.

DCCA is an ecologically robust direct ordination technique, which can be used to quantitatively estimate species turnover, scaled in terms of beta diversity (SD units) (ter Braak & Verdonschot,

1995) which allows the direct comparison of different sites (Birks, 2007). DCCA analyses were conducted on downcore species assemblages constrained to sample age as the sole environmental variable, in order to estimate and compare diatom compositional change over approximately the last 200 years among the study sites, following Smol et al. (2005). For all sedimentary diatom profiles, DCCAs were conducted on the full 200-year diatom sequence from each lake to estimate overall assemblage compositional turnover over the recent past. In addition, to examine the effect of recent warming (reference lakes) versus the compounded effect of warming and

slumping (slump-affected lakes), we measured the amount of species turnover for each sequence

prior to the onset of the sustained increasing regional temperature trend for western North

America (based on dendrochronological techniques; Szeicz & MacDonald, 1995), the amount of

species turnover post-1910 and the amount of species turnover post-slumping [timing defined by

information derived from air photo analyses (Table 3)]. These a priori designations were assigned based on the major identified stressors affecting the lakes in order to estimate how much compositional change could be accounted for by each stressor. To determine whether the

amount of total species turnover estimated in each stratigraphic diatom sequence was comparable

to ecologically significant diatom changes recorded throughout other regions of the circum-

Arctic, we used the mean beta diversity of >1.0 SD established by Smol et al. (2005) derived

from diatom records in undisturbed temperate reference sites.

Trends in the relative abundance of benthic fragilarioid taxa (primarily taxa of the genera

Staurosirella, Staurosira and Pseudostaurosira) in each lake over time were standardised (using

z-scores) and combined into two records (reference and slump-affected sites). These standardised

trends were compared to the yearly air temperature records from the Inuvik climate station using

Spearman Rank correlation analyses (temperature data were not smoothed prior to analyses).

Species diversity (Hill’s N2; Hill, 1973) was calculated on the relative abundances of periphytic

(organisms living associated with a substrata, i.e. non-planktonic taxa) diatoms, after removal of

the benthic fragilarioid species. All temporally dependent data analyses were restricted to

intervals with age estimates since about 1800 because associated dating errors from ages

extrapolated beyond this time frame were undesirable. Relative frequency diagrams displaying

expanded diatom assemblages for all 12 lakes are included as supporting information (Figures

S4–S9). See Appendix S1 in supporting information for an expanded description of the methods

used in this study.

Table 3 Estimated timing of slump (re)initiation ⁄ acceleration based on air photo evidence for the six slump-affected lakes analysed

Results

The sedimentary diatom assemblages from all 12 lakes in this study record a number of striking changes over the last 200 years (Fig. 3). Four of the six reference (i.e. ‘a’) lakes record an increase in the relative abundance of planktonic diatom taxa (primarily species of Discostella,

Cyclotella, Cyclostephanos and Asterionella), with the earliest increase occurring about 1900

(Fig. 4). The six slump-affected (i.e. ‘b’) lakes record several different diatom changes over the recent past, including increases in planktonic species relative abundance in four lakes (Fig. 4) and strong increases in the relative abundance and diversity of non-fragilarioid periphytic diatom taxa (primarily species of Achnanthes, Navicula, Nitzschia; Figs 3 & 5) in five of the six lakes studied.

Estimates of species turnover as beta diversity over the past 200 years, obtained from

DCCA constrained to sample age for all lakes (slump-affected and reference), were deemed ecologically significant as they exceeded the mean reference value of 1.0 SD unit, sensu Smol et al. (2005). However, in all cases, the slump-affected lakes exhibited higher species compositional change over the last 200 years than the paired reference lakes (Fig. 3). The magnitude of diatom turnover in these sub-Arctic slump-affected lakes is comparable to some of the highest diatom beta diversity values recorded in High Arctic systems by Smol et al. (2005).

Fig. 3 Stratigraphic diatom profiles from each of the 12 lakes analysed, showing recent assemblage shifts over the last c. 200 years, plotted by estimated 210Pb date (secondary axis core depth). Beta-diversity values (in SD units based on DCCA for the entire c. 200 year record) are included in boldface next to each lake name. Solid horizontal lines represent the onset of regional climate warming, c. 1910. Horizontal dashed lines represent the rapid temperature increase observed from instrumental climate records at Inuvik, c. 1970. For each slump-affected lake, grey dashed, dotted line represents the approximate timing of known slump re-initiation ⁄ acceleration, based on air photo and ground observational evidence. All data are expressed as the relative frequency percentages of each taxon or grouped taxa. S:D index represents the number of scaled chrysophyte remains relative to number of diatom valves. C:D index represents the number of chrysophyte stomatocysts relative to the number of diatom valves enumerated.

Fig. 3 (Continued)

Temporally constrained DCCAs conducted on a priori defined subsets of the diatom assemblage data show that, for each reference lake, beta diversity was greater post-warming than prior to recent warming (Fig. 6). In each slump-affected lake, DCCAs were conducted to classify the change due to the cumulative effects of warming and thaw slumping. For five of the six slump-

Fig. 4 Summary of the relative abundance of all planktonic diatom taxa for (a) the six reference lakes, (b) the six slump-affected lakes. Dates are extrapolated back to 1800 based on the average sedimentation rate of the intervals with the oldest 210Pb dates (Binford, 1990). Maximum lake depth is included for each lake in (a) and (b) in the legend.

Fig. 5 Deviation from the pre-1900 mean of the Hill’s N2 diversity conducted on the non- fragilarioid periphytic diatom assemblage for (a) the six reference lakes and (b) the six slump- affected lakes, since c. 1800.

affected systems, species turnover was greater post-1910 (incorporating changes due to both

warming and thaw slumping) than in the corresponding paired reference lake (Fig. 6). In addition

to greater pre- and post-warming changes, the amount of assemblage turnover that occurred

following the acceleration (or increased intensity) of thaw slumping represents more than half

(and in some cases as much as c. 95%) of the biological change that has occurred since 1910. In

one lake pair (7a ⁄ b), the magnitude of the compositional turnover post-warming was greater in

the reference site; however, the overall biological turnover in the system since c. 1800 is

nevertheless larger in the slump-affected lake (Fig. 3).

The relative abundance of planktonic diatom taxa (rare in earlier intervals) increased in

four of the six reference lakes (all except lakes 6a and 9a), with the deepest lake (5a; Zmax = 10.5 m) exhibiting an increase in the first decade of the 20th century (Table 2, Fig. 4). The onset of planktonic diatom abundance increases in the second deepest reference site, Lake 14a (Zmax = 7.5 m), occurred about 1930. Increased planktonic abundance in lakes 2a and 7a (Zmax = 6.1 and 2.7

m, respectively) occurred coincident with increased warming trends observed from the

instrumental record, about 1970 (Fig. 4). Recent increases in centric, planktonic Discostella

pseudostelligera (Hustedt) Houk and Klee (synonymous with Cyclotella pseudostelligera) were

the most common diatom shift observed in these lake systems (Fig. 3). In addition to increases in

D. pseudostelligera, increased relative abundance of pennate planktonic species such as

Asterionella formosa Hassall were also observed in the reference systems and is particularly

notable in Lake 14a (Fig. 3). As would be expected, planktonic diatoms were a relatively

unimportant component of the species assemblages in the shallowest of the reference lakes (6a,

2.3 m deep; 9a, 2.7 m deep), accounting for <2% relative abundance of the assemblage over time

(Fig. 4, Figs S6 & S8). However, diatom assemblages in the more recent sediments of these two

Fig. 6 Beta-diversity (SD units) determined before ⁄ after the timing of a priori defined stressors. For each reference site, beta-diversity was calculated before and after the onset of regional climate warming in c. 1910. For each lake, pre-warming (i.e. pre-1910; blue bar) was compared to post-warming (1910 to present; red bar) beta-diversity. It is assumed that for each reference system, warming represents the sole stressor over the recent past. In slump-affected lakes, because of the additional stressor of thaw slumping, beta-diversity after the inferred timing of slump initiation (post-slump; based on the estimated timing of slumping from sources such as air photos) was also assessed to determine the cumulative biological response to the combined stressors or thaw slumping and regional warming and is plotted as the proportion of the post- warming beta-diversity (red and yellow hatched bar). Inset (a) shows the location of Lake 9b, c. 45 km north of the other study sites. *Diatom records from Lake 14b did not extend beyond 1910, and thus no pre-warming data are available. **The early timing of slumping in lakes 7b, 9b and 14b result in small post-warming, pre-slumping assemblage turnover estimates.

shallow reference sites were more species-rich than in older sediments. The increase in

planktonic taxa in our reference lakes coincides with a decrease in the relative abundance of

benthic fragilarioid taxa, which dominate the oldest sediments of every lake (impacted and

reference) studied (Fig. 3). These recent decreases in the relative abundance of benthic fragilarioid taxa were recorded in all six reference lakes and therefore were used to make comparisons to the instrumental climate data. Standardised trends in fragilarioid abundance

(using z-scores) were compared to the climate record available from Inuvik since the late 1920s

(Fig. 2). The decline in fragilarioid taxa relative abundance is significantly correlated to both the

increasing annual (R = -0.64, P < 0.001) and winter (R = -0.59, P < 0.001) temperature trends in

the region, which escalated notably from the mid-1960s to the present (Fig. 2).

Rapid increases in the relative abundance of planktonic diatoms were also observed in

four of the six slump-affected lakes, 2b (c. 1968), 5b (c. 1960), 7b (late 1990s) and 14b (mid-

2000s). The diatom taxa that showed an increase varied among systems (Fig. 3), with D.

pseudostelligera increasing in lakes 5b and 7b, species of Cyclostephanos increasing in Lake 2b

and Cyclotella ocellata Pantocsek dominating the recent diatom assemblage in Lake 14b. The

other two shallower, slump-affected systems, lakes 6b and 9b, recorded assemblages composed

of 100% benthic ⁄ periphytic diatom taxa throughout the recent past (Fig. 3). As in the reference

lakes, increased planktonic abundance coincided with decreasing relative abundance of benthic

fragilarioid taxa in the slump-affected lakes. The decline of benthic fragilarioid relative

abundance (combined using z-scores for all six slump-affected lakes) was significantly

correlated to both increasing annual (R = -0.63, P < 0.001) and winter (R = -0.71, P < 0.001)

temperature trends (Fig. 2).

In addition to increases in planktonic relative abundance, five of the six slump-affected

lakes also recorded interesting changes among the non-planktonic diatom taxa. Although periods

of slump activity initiated at different times, and the intensity of disturbance varied in each of the

slump-affected lakes (Fig. 3), a common trend was an increase in the relative abundance of non-

fragilarioid periphyton (taxa living attached to substrata) coincident with the inferred timing of

slumping. For example, a strong, rapid increase in the abundance of Amphora inariensis

Krammer and species of Achnanthes occurred prior to about 1850 in Lake 2b (Fig. S4), where an old thaw slump was observed on early air photos (pre- 1950). Following this earlier thaw slump event, an increase in the abundance of Nitzschia taxa was coincident with a rapid increase in planktonic diatoms in Lake 2b in the late 1960s, corresponding with a more recent slump event at this site (Fig. 3). Similarly, in Lake 5b, increased relative abundance of periphytic Nitzschia,

Navicula and Achnanthes taxa occurred at the time of the inferred slump event (Lake 5b is

known from air photo analysis to have had no history of thaw slumping until the early 1980s),

whereas a large, rapid increase in Achnanthes taxa was observed at the time of inferred slump

activity in the mid- to late 1980s in Lake 6b (Fig. 3). In Lake 7b, a lake which is known to have a

long history of thaw slump activity, prior to 1950, an increase in the periphytic taxa Amphora,

Achnanthes and Diploneis occurred (Fig. S7), a trend that was also observed (although more

subtly) in the shallow and most northern slump-affected site, Lake 9b in the early 1950s (Fig. 3).

An exception to this trend was observed in slump-affected Lake 14b, known from observations

to have undergone recent slumping around 2000 and is dominated by nearly 80% planktonic taxa

in the upper sedimentary intervals with no concurrent increase in non-fragilarioid periphytic

diatom relative abundance. Species diversity (Hill’s N2) of periphytic taxa (excluding the

benthic fragilarioid taxa which show a trend of decreasing relative abundance in all lakes)

35 likewise increased in these five slump-affected sites over the past 200 years (Fig. 5). Increases in the abundance of periphytic diatoms were not observed in any of the reference sites, with one notable exception, Lake 5a, which recorded an increase around 1900 (Fig. 3). Despite its initial classification as a reference lake, Lake 5a may have been impacted by thaw slumping in the past, as suggested by recently identified, well-vegetated slope concavity characteristic of old stabilised slope disturbances.

The number of chrysophyte scales (a holoplanktonic algal group) increased relative to diatoms (S:D index) in five of the six reference lakes over the past century (Fig. 3). Similar to the planktonic diatom changes, these increases varied in magnitude and timing, with the earliest increases occurring in the deeper lakes. In contrast, only two of the slump-affected lakes (5b and

14b) recorded chrysophyte scales in the recent sediments (Fig. 3). With the exception of Lake 5b prior to the late 1970s, the slumped lakes showed lower numbers of chrysophyte stomatocysts relative to diatoms (C:D index; Smol, 1985) than the corresponding paired reference lakes (Fig.

3). The ratio of chrysophyte cysts to diatom valves declined in slumped lakes 5b, 6b and 14b over time. The timing of the decline in chrysophyte cyst numbers (relative to diatoms) was consistent with the timing of changes in diatom assemblages in lakes 5b and 6b, but occurred earlier than the main diatom changes in Lake 14b (Fig. 3). The number of chrysophyte cysts

(compared to diatoms) was either stable or variable through time in the other slump-affected lakes, as well as in five of the reference lakes. Only in Lake 2a did the number of cysts decrease, beginning about 1870. While a decrease in the C:D index may indicate a decline in the number of chrysophyte cysts over time, it is also possible that this change reflects an increase in the absolute abundance of diatoms, which could occur as a result of a variety of limnological

changes, but which is difficult to assess using palaeolimnological techniques (Battarbee et al.,

2001).

Discussion

The diatom trends from the 12 paired study lakes show a number of striking changes

related to the stressors of regional climate warming and intensive, but localised thaw slumping

that are occurring in the region. The amount of biological change was greater in slump-affected

lakes, most likely as a response to the compounded effect of these two major stressors.

Nevertheless, all 12 sites show an ecologically significant change in diatom composition over

approximately the last 200 years. In all of the 12 lakes studied, the amount of biological turnover

occurring post-warming was greater than that of pre-warming. Using our paired lake

comparisons, slump-affected lakes were found to have greater biological change post-warming in

five of the six lake pairs. This is what would be expected when considering that this time frame

would encompass the cumulative effects of climate warming and permafrost thaw slumping on

the lake’s algal communities.

Regional climate warming

Increases in the relative abundance of planktonic diatoms in four of the six reference

systems suggest a response to the onset of regional warming which is estimated to have started

just after the turn of the century in this region (Szeicz & MacDonald, 1995). This increase in

planktonic diatoms has been shown to be a response to climate warming in other lakes from many Arctic, alpine and temperate systems across the Northern Hemisphere and is consistent with responses due to changes in lake ice cover, lake thermal structure, aquatic habitat,

lengthening of the algal growing season and associated water-column changes (Rühland et al.,

2008). In the deepest reference lake in this data set, this change began in the early 1900s

consistent with the initial stages of warming. Acceleration of this life strategy shift has occurred

over the last century, albeit later in the shallower reference lakes. This would be predicted given

that changes in thermal structure ⁄ stability in these lakes would be better expressed and occur

earlier in the deeper lakes (Rühland et al., 2008). Similar increases in planktonic taxa were observed in four of the slump-affected sites, suggesting that lakes that are being impacted by

thaw slumps are also recording a regional warming signal in the algal communities. The timing

of these changes based on depth are consistent with a threshold response; a subtle change in the

assemblages occurred in the deepest lakes first as the warming trend was steady and slow,

followed by more abrupt changes as climate enters a new temperature regime (as indicated by

our break-point analysis). As expected, in the shallowest lake systems (<2.5 m) in the data set

(both reference and slump-affected), planktonic diatom taxa were not an important component of

these lakes with relative abundance never exceeding 2%. Rather, these shallow systems

registered notable changes among the benthic diatoms, including declines in the previously

dominant fragilarioid taxa and the development of more complex assemblages with an increase

in the number of taxa present. Coincident with increases in planktonic diatom abundance,

decreased relative abundance of benthic fragilarioid taxa was observed in all 12 lakes studied, a change that is strongly correlated with increases in local air temperature data. This provides strong evidence that diatoms are responding sensitively to the pronounced amplification of warming observed in the region and related decreases in lake ice cover and associated changes in lake water properties and habitats. Small benthic fragilarioid taxa compete well in challenging conditions common in Arctic lakes, including prolonged periods of ice cover and cold

38 temperatures (Lotter & Bigler, 2000). Warmer temperatures and increases in the ice-free period, particularly during the Arctic summer, can lead to important changes in water-column properties, including increased thermal stability and related changes in light habitat and nutrient cycling that tend to favour the growth of small, fast growing, planktonic Cyclotella taxa (Rühland et al.,

2010). The first notable appearance and subsequent increase in the number of chrysophyte scales coincident with increases in planktonic diatoms in five of the six reference study lakes as well as slump-affected lakes 5b and 14b is consistent with a response to warming-induced changes in the water column and has been recorded in other palaeolimnological studies (Wolfe & Perren, 2001;

Guilizzoni et al., 2006; Ginn et al., 2010). With increased thermal stratification as a result of climate warming, the motile, scaled chrysophytes, which are able to direct their movement in the water column, are better able to outcompete non-motile taxa that require mixing to remain in the photic zone. In addition, because of their motility, scaled chrysophytes can orient themselves to take advantage of nutrients entrained in the metalimnion which occurs under strongly stratified conditions (Sandgren, 1988). Based on our data, climate warming has resulted in an ecologically significant increase in the abundance of planktonic algae over the last 200 years in eight of the

12 lakes studied, with the earliest changes occurring in the deeper lakes.

Impacts of thaw slumping on diatom assemblage structure and lake habitat

Retrogressive thaw slumping resulted in abrupt and striking changes to the diatom assemblages in several of the lakes studied; however, the inferred timing and principal biological response to slumping varies between the slump-affected systems. There has been a recent regional increase in slump activity since the 1970s in association with rising air and permafrost temperatures (Lantz & Kokelj, 2008), but the magnitude and intensity of individual thaw slumps

varies significantly across the landscape, resulting in site-specific differences in geochemical and

sedimentary inputs to impacted lakes. Furthermore, the biological response to thermokarst

impacts on these lakes is influenced by inherent limnological differences, as well as the

interaction of multiple stressors, particularly climate warming, and thus the lack of coherence in

the timing and the nature of the diatom response are unsurprising. In five of the slump-affected

lakes (14b being the exception), an increase in the relative abundance and diversity of non- fragilarioid periphytic diatom taxa is observed in association with the (re)initiation or intensification of thaw slump activity, suggesting the development of a more complex assemblage of diatoms associated with substrata on the lake bottom. Increased water clarity resulting from decreased DOC concentrations and decreased overall water colour is one of the known responses following thaw slumping, stabilisation and settling of suspended sediments

(Kokelj et al., 2005, 2009b; Thompson et al., 2008). The resulting enhancement in light penetration has been associated with increased development of littoral aquatic macrophyte and moss communities in slump-affected lakes (Mesquita et al., 2010). This increased water clarity would result in an increase in habitat availability for the colonisation of periphytic diatoms

(including increased macrophyte communities, as well as other substrata) and can explain the increased relative importance and diversity of the non-fragilarioid periphytic diatom flora observed in these lakes. Increases in periphyton abundance observed in lakes 2b (before 1850),

5b (late 1970s), 6b (mid-1980s), 7b (before 1850) and 9b (early 1950s) are probably all biological responses to polycyclic thaw slumping in these systems (Kokelj et al., 2009a) and

generally correspond well to the timing of slump (re)initiation ⁄ acceleration inferred from

independent lines of evidence, such as air photos (S.V. Kokelj, unpublished data). It is important

to note that a similar increase in relative abundance or diversity of non-fragilarioid periphytic

diatom was not observed in the respective reference lakes, with the exception of Lake 5a, a site

that may have a history of thaw slump activity in the more distant past, despite its initial classification as a reference lake.

Lake 14b, having a large, highly active thaw slump, was the only system that did not record a relative increase in non-fragilarioid periphytic diatom abundance. Instead, an abrupt and

almost complete turnover of the assemblage from dominance by benthic fragilarioid taxa to

dominance by planktonic species, in particular Cyclotella ocellata, occurred in the early-2000s.

This increase occurred much later than in Lake 14a, its paired reference system, which recorded an increase in planktonic species around 1930 consistent with the increasing temperature trends from the region. As both lakes currently have similar maximum depths, this suggests that the rapid shift in diatom taxa in Lake 14b is likely the result of the cumulative effects of warming and recent intensification of thaw slump activity occurring at this site, as a large slump is known to have initiated about 2000 AD. A likely explanation for this rapid habitat shift is that the very large and highly active slump is contributing significant amounts of allochthonous material to the lake. This intense disturbance is probably making the benthic zone inhospitable to diatom growth, accounting for the rapid decrease in benthic fragilarioid relative abundance coincident with the known re-initiation of this slump. While measurements of turbidity are not elevated in comparison with other slump-affected lakes, slump debris flow activity resulting in pulses of high turbidity at certain times of the year is likely. Laboratory testing has shown that when local ice-rich tills are thawed, the high clay content can maintain a layer of fine-grained materials in suspension just above the sediment-water interface (S.V. Kokelj, unpublished data). A combination of smothering by larger-grained material and the suspension of fine-grained sediments above the lake bottom resulting in light and habitat availability limitations could

possibly explain the rapid change in habitat preference observed in the sedimentary diatom

assemblage. It is likely that once this highly active slump stabilises, increased water clarity will

promote similar periphytic diatom growth as was observed in the five other slump-affected lakes.

In addition to this decrease in benthic habitat, gradual lake-bottom subsidence, known to occur in

association with development of lake-side thermokarst (Kokelj et al., 2009a), would result in increased water depth in the area near this large slump, which could have further promoted this planktonic diatom increase. Other explanations, including an amplified response to warming due to decreased ice albedo caused by increased turbidity from this highly active slump, must also be considered. Although the particular details of the mechanism are somewhat speculative, it is clear that this rapid change in sedimentary diatom composition is a result of the initiation of this large, highly active thaw slump, combined with the regional stressor of increasing temperatures.

Similar increases in planktonic abundance coincident with the timing of recent slump activation in lakes 5b and 7b may be a similar response, although of a smaller magnitude, consistent with the lower intensity of disturbance at these sites. It is anticipated that climate warming and a rise in permafrost and lake temperatures will increase the rates of slump initiation and the intensity of these disturbances, so this mode of ecological response may become more common in the future.

Chemical changes due to slumping

Modern limnological comparisons have shown significant differences in water chemistry between reference and slump-affected lakes (Kokelj et al., 2009b). Although we infer that sedimentary diatoms are primarily tracking changes in aquatic habitat availability due to increased light penetration in all of our lakes, diatom changes in Lake 2b are an exception and are likely in response to strong chemical changes. In slump-affected Lake 2b, an increased

42 abundance of non-fragilarioid periphytic diatoms suggest thaw slumping was initiated some time before 1850 in this system, with these taxa responding indirectly to increased water clarity, as discussed earlier. Air photo analysis indicates that slumps surrounding the lake in the 1950s were present, but were well vegetated and stable. The most significant change in the diatom assemblage in Lake 2b occurred in the late 1960s, when a rapid increase in the abundance of planktonic Cyclostephanos taxa occurred, taxa that are classified as eutrophic indicators in other regions (Hausmann & Kienast, 2006; Laperrière et al., 2008). The timing of this change in the late 1960s corresponds to an intense wildfire that burned into the tundra uplands, including the area around Lake 2b in 1968 (Landhäusser & Wein, 1993). As a major ecosystem disturbance, wildfire resulted in both catchment-wide active layer deepening (Mackay, 1995) and intensification of thaw slump activity (Kokelj et al., 2009a). This acute disturbance, combined with this system’s history of slump activity resulting in well-vegetated slumps, can lead to re- initiation of slumping as increased shrub cover leads to greater snow accumulation and increased ground temperatures (Kokelj et al., 2009a). Modern chemical sampling has shown that slump- affected lakes generally have lower nutrient concentrations than reference sites (Thompson,

2009). However, the results of the diatom analyses from Lake 2b, the site with the highest TP levels in the data set (about 80 µg L-1, an exceptionally nutrient-rich lake for Arctic regions, comparable to ponds impacted by ornithogenic inputs; Michelutti et al., 2010), suggest that in this lake, fire-induced retrogressive thaw slumping in conjunction with catchment-wide active layer deepening did result in the eutrophication of this system. The lake remains eutrophic c. 40 years later, despite slump stabilisation. Lake 2b is the only system in our data set for which we infer slump-initiated nutrient enrichment. Unique differences in the catchment chemistry ⁄ geology of this lake likely resulted in this anomalous response to thaw slump initiation.

Changes in chrysophyte abundance may also represent a response to chemical changes

following thaw slumping. The number of chrysophyte stomatocysts (compared to diatoms) was

lower in the slump-affected lakes than in the reference sites, with the exception of Lake 5b. Until

recently, Lake 5b was pristine and stomatocyst abundance was high. Recently, abundance of

chrysophyte cysts sharply declined, coincident with the main slump-initiated changes in the

diatom assemblage composition. In addition, increasing abundance of scaled chrysophytes,

probably related to climate warming, was only recorded in two slump-affected lakes, compared

to in five of the six reference sites. This suggests chrysophytes may also be responding to

changes as a result of thaw slumping, such as increasing ionic concentrations. Previous studies

have found that in general chrysophytes are more abundant in low-conductivity lakes (Siver,

1995) and that in some locations ionic strength is as important as pH for structuring chrysophyte

communities (Siver & Hamer, 1989). It is possible that increasing ionic strength following

slumping may be resulting in decreased abundance of chrysophyte stomatocysts as well as

inhibiting increases in scaled chrysophyte populations. The timing of changes in these biological

indices corroborate the diatom assemblage changes, providing a more robust assessment of the

timing and nature of biological changes as a result of thaw slumping.

In this remote and ecologically important region of Arctic Canada, we have explored both

the effects of warming and the added stressor of permafrost thaw on the biological response of a

unique series of paired lakes with a range of limnological conditions. Palaeolimnological

analyses of lakes impacted by permafrost degradation show that thaw slumping results in a spectrum of ecologically significant biological changes to aquatic ecosystems and that these changes vary with the intensity of disturbance and the nature of the lake system. Lakes impacted

by thaw slumping exhibited greater biological change than reference sites, highlighting that the

44 compounding effects of both warming and slump events initiate a greater biological response than either of these stressors alone. The phycological responses to slumping appear to be primarily linked to physical changes in habitat and emphasise that there is the potential for significant, rapid change in some systems, under conditions that vary with the intensity of disturbance and lake characteristics and which cannot be easily predicted. Using detailed changes in sedimentary diatom assemblages, combined with other siliceous algal indicators, the biological response and approximate timing of onset following thaw slumping can be elucidated.

As climate-induced permafrost degradation is predicted to become more widespread throughout the circumpolar Arctic, understanding the ecological impacts of thermokarst are essential if we are to predict the ecosystem-level changes that will occur to sensitive freshwater ecosystems.

This is particularly important given the essential ecological services these systems provide to the water-rich landscape of the north.

Acknowledgments

This work has been supported by Natural Sciences and Engineering Research Council

(NSERC) of Canada and Polar Continental Shelf Program funding to MFJP, JMB and JPS, and an NSERC CGS-D scholarship and Northern Scientific Training Program funding to JRT. We thank the Cumulative Impact Monitoring Program of Aboriginal Affairs and Northern

Development Canada for support. We thank the Aurora Research Institute and Canadian

Helicopters (Inuvik) for logistical assistance. Field assistance from Peter deMontigny is gratefully acknowledged. We thank Jennifer Korosi and two anonymous reviewers for comments that improved the quality of the manuscript.

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Supporting information

Figure S1 Radioisotopic activity of 210Pb (circles), 226Ra (squares) and 137Cs (crosses), as well as the sediment age determined using the constant rate of supply model (with associated standard errors) for lakes 2a, 5a, 6a and 7a.

Figure S2 Radioisotopic activity of 210Pb (circles), 226Ra (squares) and 137Cs (crosses), as well as the sediment age determined using the constant rate of supply model (with associated standard errors) for lakes 9a, 14a, 2b, and 5b.*No 137Cs activity was detected in the Lake 5b sediment core.

Figure S3 Radioisotopic activity of 210Pb (circles), 226Ra (squares) and 137Cs (crosses), as well as the sediment age determined using the constant rate of supply model (with associated standard errors) for lakes 6b, 7b, 9b, and 14b.

Figure S4 Relative frequency diagrams of taxa >5% relative abundance for lakes (a) 2a and (b) 2b.

Figure S5. Relative frequency diagrams of taxa >5% relative abundance for lakes (a) 5a and (b) 5b. 55

Figure S6 Relative frequency diagrams of taxa >5% relative abundance for lakes (a) 6a and (b) 6b.

Figure S7 Relative frequency diagrams of taxa >5% relative abundance for lakes (a) 7a and (b) 7b.

Figure S8 Relative frequency diagrams of taxa >5% relative abundance for lakes (a) 9a and (b) 9b.

Figure S9 Relative frequency diagrams of taxa >5% relative abundance for lakes (a) 14a and (b) 14b.

Appendix S1 - Supplementary methods information

Site Description

This study focuses on assessing changes to lake ecosystems in the uplands east of the

Mackenzie Delta, near the northern town of Inuvik, Northwest Territories, Canada (Fig. 1).

Climate in the region is seasonally extreme. Winters are cold due to the shielding effect of the cordillera, which blocks warm, maritime Pacific air, ensuring cold Arctic air masses dominate the region (Dyke, 2000). In contrast, during the summer months, southern air masses move northward, giving the region the warmest summer temperatures in Canada for its latitude (Dyke,

2000). The study region was covered by the Wisconsinan ice sheet which reached a maximum extent ~38.8 thousand years ago (Duk-Rodkin & Lemmen, 2000). The region is underlain by thick, continuous permafrost, with taliks that penetrate through the permafrost present under lakes that do not freeze to the bottom due to the insulating properties of water (Burn, 2002).

Near-surface permafrost is enriched with solutes (particularly calcium and sulphate, which are glacially derived from carbonate and shale bedrocks) in comparison to the overlying active layer

(Kokelj & Burn, 2003, 2005). Vegetation communities common in the lowland shrub tundra just north of treeline include primarily members of the Cyperaceae, especially Eriophorum and

Carex (Ritchie, 1984), although shrub birch (Betula nana subsp. exilis), green alder (Alnus viridis subsp. fruticosa), and willow (Salix spp.) are common (MacDonald, 2000). Patches of black (Picea mariana) and white (Picea glauca) spruce in a tundra matrix are common where climatically favourable sites exist (Ritchie, 1984).

Water chemistry analyses, sediment core collection and diatom analyses

Samples for water chemistry analyses were collected from the central portion of the lake approximately 1 m below the surface. Samples for determination of major ion concentrations 60

were analyzed by ion chromatography at the Taiga Environmental Laboratory (Yellowknife,

NT). Samples for dissolved and unfiltered total phosphorus (TP) concentration determination

were analyzed using the colorimetric method for low yield results at the National Laboratory for

Environmental Testing, Canadian Centre for Inland Waters (Burlington, ON). For lakes from which sediment was sampled through the winter ice, nutrient samples were collected the following open-water season. Lakes 2a, 2b and 5b were not re-sampled, and thus unfiltered TP concentrations were taken from Thompson (2009). Further water chemistry analyses for the 12 study lakes are available in Kokelj et al. (2009b) and Thompson (2009), including other nutrients

such as total dissolved nitrogen, which was not sampled at time of sediment sampling.

Sediment cores from the 12 lakes studied were collected from the centre (deepest location) of each lake over a two year period, in April of 2007 (coring through the late winter ice) and in July of 2008 (coring from an inflatable raft). In all cases lakes were accessed by helicopter. Sediment cores were collected using a Glew-type (1989) gravity corer (internal

diameter 7.62 cm) and sectioned using a Glew (1988) vertical extruder. To obtain high temporal

resolution paleolimnological profiles, cores were sectioned at 0.25 cm (for the top 15 cm) and

0.5 cm (for the remainder of the core) intervals, and stored in individual WhirlPak® bags at 4 °C

until analysis. Sediment age estimation was established on 10-16 sedimentary intervals from

each core using 210Pb and 137Cs radioisotopes following standard methods for gamma dating

(Schelske et al., 1994; Appleby, 2001). For all sediment cores, the constant rate of supply (CRS)

model (Appleby & Oldfield, 1978) was used to calculate dates, and whenever possible, the peak

in 137Cs (corresponding to 1963) was used to corroborate the 210Pb dates (Appleby, 2001). For

each core the cumulative dry weight of the sediment core was compared to the log-transformed

unsupported 210Pb activity, in order to detect changes in sediment accumulation over time

(deviation from a linear fit used to detect changes). Linear regression for all cores were found to

be strong (r2 >0.60), with the slump-affected lakes showing no difference from reference sites, with the exception of Lake 9b, which showed a somewhat less robust relationship (r2 = 0.45).

Laboratory methods for siliceous indicator identification followed Battarbee et al. (2001).

In summary, sediment was digested in a mixture of sulphuric and nitric acids, and heated in a

water bath to facilitate the digestion of the organic matrix. After being allowed to settle, samples

were rinsed daily until a near neutral pH was established. Aliquots of diatom slurry were plated

onto coverslips, and mounted on microscope slides using the high-refractive index mounting medium Naphrax© (Brunel Microscopes, Wiltshire, UK). For each sedimentary interval, at least

300 diatom valves were identified and enumerated along transects at 1000x magnification.

Diatoms were identified using a variety of sources (primarily Krammer & Lange-Bertalot, 1991,

1997, 1999, 2000; Cumming et al., 1995; Fallu et al., 1999).

Statistical Analyses

Climate data from Inuvik were obtained from the Adjusted Historical Canadian Climate

Database (http://www.cccma.ec.gc.ca/hccd/). The SiZer (Sonderegger, 2010) package for the R

statistical environment (R Development Core Team, 2010) was used to conduct a piecewise

linear regression (Toms & Lesperance, 2003) on these climate data, with 95% confidence

intervals determined by bootstrapping (n=1000). Longer term climate reconstructions (~A.D.

1750 to 1988) based on dendrochronological analyses of samples (Szeicz & MacDonald, 1995;

Wilson et al., 2007) were obtained online from the National Oceanic and Atmospheric

Administration (NOAA) National Climate Data Center.

Relative frequency diagrams of the most common diatom taxa were prepared using the computer program Tilia v1.7.16 (Grimm, 2011), with a constrained incremental sum of squares

(CONISS) cluster analysis included (Grimm, 1987). Detrended canonical correspondence analyses (DCCA) were conducted using CANOCO v4.5 (ter Braak & Šmilauer, 2002). The approach used here follows Smol et al. (2005) where compositional change in diatoms, chrysophytes, chironomids and cladocerans over the past 150 years was quantified and compared among a suite of Arctic lakes. For all sedimentary diatom profiles, DCCAs were conducted using square-root transformations, no down-weighting of rare taxa and detrending by segments.

Trends in the relative abundance of benthic fragilarioid taxa in each lake over time were standardized using z-scores (i.e. standard scores) and combined into two records (reference and slump-affected sites) by calculating the mean z-score for each 210Pb year estimate where multiple samples existed. These standardized trends were compared to the yearly air temperature records

(mean annual and mean winter) from the Inuvik climate station using Pearson correlation analyses (temperature data were not smoothed prior to analyses). Significance levels were adjusted using Bonferroni probabilities. Hill’s N2 diversity (Hill, 1973) determinations were conducted using the vegan package for R (Oksanen et al., 2010).

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Chapter 3

Arctic coastal freshwater ecosystem responses to a major saltwater intrusion: a landscape-

scale palaeolimnological analysis

Abstract

Because of decreasing sea-ice extent and increasingly frequent Arctic storms, low-lying coastal ecosystems are at heightened risk from marine storm surges. A major Arctic storm event originating in the Beaufort Sea in September 1999 resulted in the flooding of a large area of the outer alluvial plain of the Mackenzie Delta (Northwest Territories, Canada), and has been previously shown to have caused unprecedented impacts on the terrestrial ecosystems on a regional scale. We use diatoms preserved in lake sediment cores to gain a landscape perspective on the impact of the storm on freshwater systems, and to determine if other such events have occurred in the recent past. Our results indicate that five lakes located at the coastal edge of the low-lying Mackenzie Delta show strong, synchronous, and previously unobserved increases in the relative abundance of brackish-water diatom taxa coincident with the timing of the 1999 storm surge. These changes were not observed at a control site located farther inland. The degree to which the storm surge impacted the chemical and biological limnology of the lakes varied, and was not explained by measured physical variables, suggesting the degree of impact is likely related to a combination of factors including distance from the coast, the size:volume ratio of the lake and its catchment, and water residence time. We show that the 1999 storm surge resulted in unmatched broadscale impacts on the freshwater ecosystems of the outer Mackenzie Delta, and that while minimal recovery may be occurring in some of the systems, the lakes studied remain chemically and biologically impacted more than a decade after the inundation event.

Keywords: diatoms, Mackenzie Delta, palaeolimnology, saltwater inundation, storm surge

Introduction

An increased frequency and intensity of marine storms is an anticipated consequence of climate change (Sepp and Jaagus, 2011). These storms, and the resulting storm surge events, have the potential to cause widespread impacts on sensitive coastal ecosystems, especially those in the circumpolar Arctic, where decreased sea ice and higher sea levels, coupled with increasingly variable storminess, may increase the vulnerability of these ecosystems (Nicholls and Cazenave, 2010; Simmonds and Keay, 2009). In September of 1999, a particularly large storm resulted in a saltwater intrusion event that inundated a large area (>10,000 ha) of the low- lying alluvial plain of the outer Mackenzie Delta (Kokelj et al., 2012; Manson and Solomon,

2007; Pisaric et al., 2011). This saltwater inundation caused significant changes to terrestrial vegetation across the impacted area (Kokelj et al., 2012). Modern limnological analyses suggest that lakes across the outer alluvial plain were impacted by this storm surge event, and that elevated ionic concentrations persist more than a decade after the inundation (Pisaric et al.,

2011). Because of a lack of long-term monitoring of limnological conditions, palaeolimnological techniques are necessary in order to infer conditions in the region prior to the 1999 storm surge, and to assess the effects of the storm on these ecosystems (Smol, 2008).

Sedimentary proxy records have been commonly used to infer the impact of large-scale storms (e.g. Liu and Fearn, 2000). Palaeotempestology refers to the science of tracking past tropical cyclone activity using proxy and historical records (Horton and Sawai, 2010), in particular hurricanes/typhoons, and has historically been used to analyze these types of catastrophic storms (e.g. Donnelly and Woodruff, 2007; Liu and Fearn, 1993; Parsons, 1998;

Williams, 2009). Similar methods have not been widely applied to smaller-scale storm events, particularly in Arctic regions. In addition, palaeoenvironmental studies of major storm frequency

68 are most commonly applied to coastal marshes, lagoons or lakes that are already saline, not freshwater systems which may have undergone salinization as a result of storm surge events.

Palaeolimnological methods provide the potential for assessing both the frequency and impacts of past storm surge events on coastal lakes. Diatoms (algae of the division Bacillariophyta) are a well-suited, and widely used, biological indicator because of their abundance in both freshwater and marine ecosystems, their well-preserved siliceous cell walls, and the fact that many taxa have well defined optima for a wide range of environmental variables, including salinity (Smol and Stoermer, 2010). In a previous study, Pisaric et al. (2011) showed a striking shift from fresh to brackish water diatom taxa as a result of the September 1999 storm surge in a small coastal lake of the outer Mackenzie Delta, and inferred no other saline intrusions in the lake’s >1000 year history. However, to date, the impact on the freshwater biology of the region has only been analyzed in this one lake (Deasley et al., 2012; Pisaric et al., 2011), and the geographical extent of the biological impact on freshwater systems of the outer delta remains unknown. While

Pisaric et al. (2011) provided the first analysis of the impact of this storm on the limnology of the region, there exists the potential for considerable variation in the response of different lakes across the outer delta, as little is known about the variability in limnological and geological conditions in the lakes of this region. Here, we apply identical palaeolimnological techniques to a broader set of lakes in order to assess the impact this large storm surge event had on freshwater ecosystems at a landscape scale. We hypothesize that all of the low-lying lakes of the outer delta that were inundated by the 1999 storm surge will show increased abundances of brackish-water diatom taxa coincident with this event, though the magnitude of this response may vary as a result of specific conditions in each lake, including the degree to which the storm surge impacted the system.

Methods

Site description

The Mackenzie Delta is Canada’s largest delta and the second largest Arctic delta globally, covering approximately 13,000 km2 on the Beaufort Sea coast of Canada’s Northwest

Territories (Burn and Kokelj, 2009) (Figure 1). The Delta plain has a maximum elevation of approximately 10 m above sea level (a.s.l.) at its apex more than 200 km from the coast

(Rampton, 1988). Owing to the long, gradual slope of the delta, storm surges originating in the

Beaufort Sea have the potential to inundate large areas of low-lying alluvial terrain (Mackay,

1963). On 23–24 September 1999, a large-magnitude storm surge resulted in an increase in water level of more than 2 m in the channels of the Mackenzie Delta, and thus is believed to have inundated the low-lying areas within ~20–30 km of the coast. This storm event was the most extreme recorded during the 1990s, based on its duration, wind speed and intensity (Kokelj et al.,

2012). Scientific as well as the local indigenous knowledge of the Inuvialuit have shown the storm surge caused widespread increases in soil salinity and vegetation mortality, resulting in a

‘dead zone’ that is apparent from ground and remote sensing analyses (Figure 1; Kokelj et al.,

2012). In order to better understand spatial patterns in the impact of the 1999 storm surge on lakes of the outer delta, sediment cores were obtained from six lakes. Four sites (assigned the code ‘DZO’ to delineate location within the ‘dead zone’) are located at the outer edge of the delta, at the leading edge of the impact of the saltwater inundation (Table 1, Figure 1). One additional study lake has ionic chemistry values which appear somewhat elevated from control sites, and is classified as a transition ‘T’ site. In addition, one site, located ~45 km inland at an upland location which suggests it was not impacted by the 1999 saltwater inundation is considered the control ‘C’ site for this study (Table 1). The lakes vary in size (3.5–228 ha) and

Figure 1. The location of the study area within the outer Mackenzie Delta, shown in the context of Canada. The black outline shows the approximate extent of the impact from the 1999 storm surge based on before and after LANDSAT imagery. Black circles represent sites for modern and palaeolimnological analyses, black squares represent sites where only modern sampling was conducted.

distance from the coast (3.6–43 km). All of the impacted lakes are low-lying in comparison with

the control site (Table 1). Ionic concentrations, in particular Na and Cl, in the impacted ‘DZO’

lakes and the transitional ‘T’ site, are elevated in comparison with the control location, as well as

other lakes studied in the delta and surrounding uplands (Kokelj et al., 2005).

Lake sampling and sample preparation

Sediment cores were collected from lakes DZO-29, C-28 and T-34 in August of 2009,

sampling from the pontoons of a helicopter using a Glew-type (Glew, 1989) gravity corer with

an internal diameter of 7.62 cm and extruded using a Glew (1988) vertical extruder. Sediment

cores from lakes DZO-2, DZO-3, and DZO-30 were collected using the same methods in July of

2010. Samples for water chemistry analyses were collected from 13 lakes (including the six lakes

from which sediment was retrieved) via helicopter during the August 2009 sampling season

(Figure 1), with water collected from the centre of the lake, approximately 1.0 m below the

surface. Major ion and dissolved organic carbon (DOC) analyses were conducted at the Taiga

Laboratory, Yellowknife, NT, with nutrient chemistry analyzed at the National Laboratory for

Environmental Testing (NLET) (Burlington ON). Preparation of samples for diatom analyses

followed standard procedures (Battarbee et al., 2001). In summary, ~0.3 g of wet sediment was

digested using a 1:1 molecular mixture of nitric and sulphuric acid and heated in a water bath

(~80°C) for ~4 h in order to facilitate digestion of the organic matrix. Samples were then rinsed

daily until neutral (5–7 rinses). Aliquots of diatom slurry were evaporated onto microscope

coverslips and mounted to microscope slides using the high-refractive mounting medium

Naphrax®. Diatoms were identified and enumerated along transects at 1000× magnification using

a Leica DMRB light microscope fitted with differential interference contrast optics and a HCX

PL Fluotar objective lens (effective numerical aperture of the combined objective-condenser =

1.3). For each interval a minimum of 300 diatom valves were identified to the lowest possible

taxonomic level using standard texts (Campeau et al., 1999a; Cumming et al., 1995; Fallu et al.,

2000; Krammer and Lange-Bertalot, 1991, 1997, 1999, 2000). Campeau et al. (1999a) was used

in order to assign salinity preferences to diatom taxa, as they analyzed habitat preference for

diatom taxa in relation to salinity in the Beaufort Sea region, near to where our study took place.

Geochronology and data analyses

Sediment age determination was conducted using 210Pb and 137Cs radioisotopic

techniques (Appleby, 2001). Cores DZO-29 and C-28 were analyzed using gamma emission

analysis (Schelske et al., 1994) with an Ortec® germanium-crystal well detector at the

Paleoecological Environmental Assessment and Research Lab (Queen’s University, Kingston

ON, Canada), with dates determined following the constant rate of supply (CRS) model

(Appleby and Oldfield, 1978) using the computer program developed by Binford (1990).

Table 1 – Select physical and chemical variables from the six study lakes from which sediment cores were collected. Cond. = specific conductivity, TP-F = filtered total phosphorus, TP-U = unfiltered total phosphorus.

Distance Surface Current Latitude Longitude from the Cond. NO DOC Ca Na Cl SO TP-F TP-U Lake Area elevation pH 3 4 (oN) (oW) coast (µS/cm) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (µg/L) (µg/L) (ha) (m asl) (km) DZO- 69 10' 135 58' 126.3 3.57 1 14955 8.08 0.44 8.1 244 2750 5920 716 8.0 16.4 2 55.5" 59.1" DZO- 69 09' 135 56' 3.5 6.49 1 12722 8.01 0.38 9.8 251 2270 5030 496 10.2 13.7 29 20.5" 52.1" DZO- 69 09' 135 57’ 8.7 7.25 1 6855 8.19 0.27 12.9 125 1120 2530 208 10.7 20.9 30 12.5" 02.0" DZO- 69 07' 135 57' 22.6 7.86 1 3090 8.63 0.28 13.1 79.9 475 1000 89 15.0 24.8 3 54.1" 08.1" 69 17' 135 31' T-34 75.3 7.58 1 567.8 8.57 0.14 9.5 33.3 57.8 120 44 12.3 18.0 28.6" 48.4" 69 04' 134 54' C-28 228.8 43.0 7 240.1 8.5 0.12 9.6 23.9 6.1 7.7 34 9.5 14.8 05.5" 52.9"

Because of the relatively short nature of the core, supported 210Pb levels were not reached for C-

28 and the average activity of 214Bi was used in order to estimate the background 210Pb activity.

Alpha counting was used to determine sediment age for cores DZO-2, -3, and -30 at MyCore

Scientific Inc (Deep River ON, Canada), with the CRS model again used for sediment age

determination. The sampling resolution of each sediment core analyzed varied between 0.5 and

7.5 years per interval (DZO-2 ~0.5–3.5 yr; DZO-3 ~1–4 yr; DZO-29 ~1–7.5 yr; DZO-30 ~1–2.5 yr; C-28 ~0.5–6.5 yr). The sedimentation rate for each sediment core was modeled based on

210Pb dating techniques (DZO-2 ~47–349 g/m2 per yr; DZO-3 ~65–466 g/m2 per yr; DZO-29

~45–291 g/m2 per yr; DZO-30 ~31–58 g/m2 per yr; C-28 ~46–358 g/m2 per yr).

Relative frequency diagrams of the most common (greater than 5% relative abundance in one interval) diatom taxa were prepared using the computer program TGView 2.0.2 (Grimm,

2004). Constrained incremental sums of squares (CONISS) cluster analyses were conducted on the complete diatom data sets for each lake in order to better elucidate the main biostratigraphic zones of change in the assemblage (Grimm, 1987). Principal components analysis (PCA) was conducted for each sedimentary sequence using the default options in CANOCO for Windows v4.5 (ter Braak and Šmilauer, 2002) following square-root transformation of the diatom relative abundance data. Linear ordination methods were selected as detrended correspondence analysis

(DCA) indicated gradient lengths for each assemblage were relatively short (1.2–1.9 standard deviation units). In order to enable a graphical comparison of assemblage changes in the six study lakes over time, PCA was calculated on the combined diatom data set, with sample scores for PCA axis 1 plotted against PCA axis 2. Hill’s N2 diversity (Hill, 1973) was conducted for each sediment core using the DCA function in CANOCO. Topographic and line maps were

74 prepared using ArcMAP 10, with topographic data courtesy of the Natural Resources Canada

CanVEC database.

Results

Relationships among limnological variables

Pearson correlation analyses of available chemical and physical variables (Pisaric et al.,

2011) were conducted in an attempt to determine if certain physical variables (such as lake area or distance from the coast) might be related to the degree of impact from the storm surge. Highly significant positive correlations (following adjustment using Bonferroni probabilities) were observed among all of the concentrations of major ions, as well as sulphate, nitrate, and specific conductivity (Table 2). In addition a significant positive correlation was observed between the concentrations of dissolved organic carbon (DOC) and filtered total phosphorus (TP-F) (Table

2). No significant correlations were observed between any of the measured chemical variables and physical variables such as lake surface area, depth or estimated distance to the Beaufort Sea coast (Table 2).

Diatom analyses

Diatom assemblages from the sediment cores in the four impacted DZO lakes and T-34 recorded a consistent appearance and increase in the relative abundance of brackish diatom taxa corresponding to ~1999 based on 210Pb dating techniques (Figure 2). The maximum relative abundance of brackish species varied, ranging from approximately 10% in T-34 to greater than

50% in DZO-29, where brackish taxa dominate the diatom assemblage (Figure 2). The

Table 2 – Pearson correlation matrix for 13 storm surge impacted lakes from the outer Mackenzie Delta sampled for water chemistry in August 2009. Coefficients in bold are significant (P<0.05) after adjustment for multiple comparisons using Bonferroni probabilities.

SA Depth Distance COND pH NO3 DOC Ca Na K Cl Mg SO4 TP-F SA 1.000 Depth 0.015 1.000 Distance 0.698 0.055 1.000 COND -0.217 0.450 -0.422 1.000 pH 0.614 -0.129 0.447 -0.595 1.000 NO3 -0.315 0.287 -0.508 0.923 -0.559 1.000 DOC -0.364 -0.391 -0.333 -0.131 0.096 0.117 1.000 Ca -0.294 0.493 -0.482 0.985 -0.635 0.939 -0.053 1.000 Na -0.193 0.454 -0.404 0.999 -0.588 0.915 -0.160 0.981 1.000 K -0.130 0.379 -0.396 0.986 -0.556 0.902 -0.193 0.956 0.990 1.000 Cl -0.195 0.470 -0.398 0.999 -0.592 0.913 -0.168 0.982 1.000 0.987 1.000 Mg -0.186 0.428 -0.430 0.995 -0.574 0.924 -0.126 0.981 0.996 0.993 0.994 1.000 SO4 -0.137 0.370 -0.397 0.997 -0.554 0.881 -0.155 0.947 0.982 0.992 0.977 0.989 1.000 TP-F -0.206 -0.269 -0.190 -0.164 0.385 0.032 0.851 -0.126 -0.182 -0.201 -0.194 -0.144 -0.137 1.000 SA= lake surface area; Distance=Estimated shortest distance from Beaufort Sea coast; COND=Specific conductivity (µS/cm); DOC=Dissolved organic carbon; TP-F=Total phosphorus (filtered)

increase in brackish species occurred rapidly in all systems following 1999. Brackish diatom taxa

were not observed in appreciable numbers (>3%) in any of the five impacted lakes prior to the

inferred 1999 sediment interval. In contrast, our control site C-28, located ~45 km inland,

recorded no brackish diatom taxa in any sediment interval of the sediment core, dating back to

~1932 (Figure 2; Pisaric et al., 2011). The relative abundance of brackish diatom taxa in the

surface sediment interval of the six study lakes was found to be strongly correlated to measured

lakewater specific conductivity recorded at the time of sampling (r2 = 0.8, p = 0.03).

Detailed palaeolimnological analysis of sedimentary diatoms from Lake DZO-2 record an

assemblage dominated by small benthic taxa of the group Fragilaria sensu lato throughout the

last ~60 years recorded in this relatively short sediment core (Figure 3a). Increased abundance of

freshwater periphytic diatom taxa including Amphora inariensis Krammer and Navicula

cryptocephala Kützing occurred beginning in the late 1980s (Figure 3a). At a core depth of 3.0

cm (~1999 based on 210Pb dating) the appearance of Craticula halophila (Grunow) Mann and

Navicula salinarum Grunow, two taxa classified as mesohalobian in the region (Campeau et al.,

1999a), and often found in brackish water habitats, increased in abundance, and represent ~25%

Figure 2. A summary of the impact of the 1999 saltwater inundation on the water chemistry and sedimentary diatom assemblages of 13 lakes from the outer Mackenzie Delta (study area outlined in Figure 1). For each of the 13 lakes sampled, the location and specific conductivity at the time of sampling is indicated below the lake name. For the six lakes from which sediment cores were obtained, the relative abundance of brackish diatom taxa (% Brackish) are displayed relative to depth (cm). The approximate timing of the 1999 storm is included based on 210Pb dating techniques. Grey arrow approximates the NW direction of the winds, which blew saltwater into the delta.

relative abundance by ~2004. They continue to represent an important component of the diatom

assemblage in the most recent sediments from Lake DZO-2 (Figure 3a).

The diatom assemblage over the last >100 years in Lake DZO-3 has been dominated by

small benthic Fragilaria sensu lato taxa, as well as by Amphora pediculus (Kützing) Grunow

(Figure 3b); however, these taxa began to decrease in the 1970s (~7.0 cm), with a corresponding

increase in N. cryptocephala occurring at this time. At a core depth of ~2.0 cm (between 1995 and 2000 based on 210Pb dating) the brackish taxa C. halophila and N. salinarum appeared for

the first time in the greater than 100 year history of the lake recorded in this sediment core, and

increased to a combined maximum abundance of ~15 % (Figure 3b). The abundances of these

two taxa were stable for approximately 5 years and then began to decrease slightly until the

present; they represent ~5 % of the surface sediment diatom assemblage of Lake DZO-3.

As with the other systems in this study, the diatom assemblage of Lake DZO-30 is

dominated by small benthic Fragilaria taxa throughout the last few hundred years (Figure 3c).

Beginning at a core depth of 16 cm, A. pediculus increased in relative abundance, and

represented 20% of the assemblage at its most abundant. At a core depth of 4.0 cm (~1999 based

on 210Pb dating) the brackish taxa C. halophila and N. salinarum occurred for the first time in the

history of the lake spanned by this sediment core, representing the last few hundred years.

Cumulatively, these brackish taxa represented ~25% of the diatom assemblage in this lake at

their peak in ~2006. While the relative abundance of N. salinarum has decreased over the last 5 years, C. halophila has increased, and thus these taxa still represent ~10% of the surface diatom assemblage in Lake DZO-30 (Figure 3c).

The diatom assemblage of T-34, the lake classified as ‘transitional’ based on elevated ionic concentrations (Na and Cl concentrations were an order of magnitude higher than C-28

Figure 3. Relative frequency diagrams of the diatom taxa found at greater than 5% relative abundance from (a) impacted Lake DZO-2, (b) impacted Lake DZO-3, (c) impacted lake DZO- 30, (d) ‘transition’ lake T-34, (e) impacted Lake DZO-29 (Pisaric et al., 2011) and (f) control Lake C-28 (Pisaric et al., 2011). Diatom species are organized by principal components analysis axis-1 species scores. Constrained incremental sums of squares (CONISS) cluster analyses are included in order to help delineate the main zones of change in the species assemblage.

when sampled in 2009; Table 1), shows a greater diversity of taxa than three of the four DZO

lakes located to the SW (Figure 3d) (Hill’s N2 diversity in the surface sediment interval T-34:

23.6; C-28: 26.4; DZO-2: 26.1; DZO-3: 14.78; DZO-29: 12.03; DZO-30: 17.4). Small benthic

Fragilaria taxa dominate the oldest sediments obtained from the lake. At a core depth of ~10 cm,

an increase in the abundance of A. inariensis, N. cryptocephala, Achnanthidium minutissimum

(Kützing) Czarnecki as well as the cumulative abundance of freshwater Nitzschia taxa occurred

(Figure 3d). An increase in the abundance of Diatoma tenue Agardh was observed at ~4.0 cm.

The brackish taxa C. halophila and N. salinarum increased in abundance at a core depth of 3.0

cm, representing 10% of the relative abundance of diatom taxa. While both taxa were observed

in very small abundances in lower sediment intervals, the increase beginning at 3.0 cm was the only sustained occurrence of these two species in this sediment record (Figure 3d). 210Pb dating

was not carried out on the T-34 sediment core.

The results of the detailed diatom analyses from lakes DZO-29 and C-28 are described in detail by Pisaric et al. (2011). The oldest intervals in Lake DZO-29 record an assemblage dominated by small benthic fragilarioid taxa, as well as A. pediculus (Figure 3e). Increased

abundances of Amphora taxa were observed over the last ~100 years in DZO-29. While small relative abundances (less than 3%) of the brackish taxa C. halophila and N. salinarum were

found throughout the sediment record, a striking increase was observed coincident with the

inferred 1999 interval. These brackish taxa continue to dominate the diatom assemblage of Lake

DZO-29 (Figure 3e). In contrast, in our a priori defined control Lake C-28, no brackish water diatom taxa were recorded over the last ~ 90 years (Figure 3f). Instead the assemblage is composed of a diverse group of benthic and periphytic diatom taxa (the most diverse assemblage

of the six lakes analyzed in this study) including species of Achnanthes sensu lato, Amphora,

Epithemia, Gomphonema and Navicula sensu lato (Figure 3f).

Principal components analysis (PCA) conducted on the combined diatom data set for all

six lakes shows the assemblage of lakes DZO-2, DZO-3, DZO-29 and DZO-30 are more similar to each other throughout the period represented by these sediment cores than to the diatom assemblages from lakes T-34 and C-28 (Figure 4). The diatom assemblage in lake C-28 remained distinct from the impacted lakes throughout the recent past. The most recent sediment intervals in lake T-34 are more similar to the impacted DZO lakes than the bottom-most sediments (Figure 4). Individual PCAs for each lake (PCA axis 1 plotted versus PCA axis 2) show all six lakes have undergone a directional change along the first axis over the recent past.

In lakes DZO-2, DZO-3 and DZO-29 a large change along the first axis occurred following the inferred 1999 interval (based on 210Pb dating), a trend that is also observed, though of a smaller

magnitude, in lakes DZO-30 and T-34 (Figure 4). Only in control Lake C-28 was no change

observed immediately post-1999, instead the main directional change in the assemblage occurred

later at this site. In no lake has the assemblage returned to the same diatom assemblage as the

bottom-most sediment intervals (Figure 4).

Discussion

Synchronous and unmatched impacts of the 1999 storm surge

The occurrence of brackish diatom taxa in the sediment records of all five impacted

lakes, coincident with the timing of the 1999 storm surge, provides strong evidence that the

saltwater inundation that resulted from this storm impacted the freshwater ecosystems of the

outer Mackenzie Delta at the landscape scale (Figure 2). The synchronous nature and timing of

Figure 4. Diatom relative abundance principal components analysis (PCA) axis 1 and axis 2 sample scores for all six study sites, calculated and plotted in a single ordination space, and for each study lake calculated individually. For individual PCA ordinations, the intervals post-1999 (based on 210Pb dating techniques) are included as black circles, with the pre-1999 intervals indicated by white circles. For the combined ordination, eigenvalues (λ) are included in the axis

title. Eigenvalues for the individual PCA ordinations were as follows: DZO-2 (λ1 = 0.50, λ2 = 0.15), DZO-3 (λ1 = 0.49, λ2 = 0.13), DZO-29 (λ1 = 0.35, λ2 = 0.15), DZO-30 (λ1 = 0.39, λ2 = 0.16), T-34 (λ1 = 0.30, λ2 = 0.20), and C-28 (λ1 = 0.29, λ2 = 0.17).

the salinization of these lakes spread across the western outer delta show the widespread impact

the storm surge had on freshwater systems of the region, beyond those shown from the previous

study conducted on only one lake (DZO-29; Pisaric et al., 2011). These results show that, as with

the impacts to terrestrial vegetation and soil geochemistry previously studied at sites across the

outer alluvial plain (Kokelj et al., 2012; Pisaric et al., 2011), diatom communities in lakes were

also impacted across the region. Palaeolimnological analyses of cladoceran assemblages have shown that the 1999 storm surge event also resulted in the loss of several invertebrate species, illustrating a synchronous impact to the zooplankton community in Lake DZO-29 (Deasley et al.,

2012).

The lack of brackish diatom species found in appreciable numbers in the lake sediments

of these five lakes at any point prior to 1999 suggests that the impacts this storm had on these

systems was unmatched over the period represented by these sediment cores (50 – >300 years

based on 210Pb dating and extrapolation). This corresponds well with geochemical evidence from

permafrost profiles, dendrochronological records and the composition of terrestrial vegetation

communities, which suggest the outer delta environment has not been ecologically impacted by

other storm surges observed from instrumental gauge records (Kokelj et al., 2012; Manson and

Solomon, 2007; Pisaric et al., 2011). Observed declines in sea ice (Comiso et al., 2008) as a

result of recent climate warming likely resulted in the 1999 storm surge being the most

ecologically significant event on record, because sea ice limits the impact of late-season storms

by minimizing the fetch over which strong winds can develop and prevents the movement of

saltwater into the normally fresh Mackenzie Delta.

While the timing and nature of the appearance of brackish diatoms among the lakes of the

outer delta was remarkably consistent, the magnitude of the abundance of these brackish taxa

varied among the five impacted systems (Figure 2). Brackish diatoms represent greater than 50%

of the current assemblage of diatom taxa in Lake DZO-29, and thus this system appears to have

been the most impacted by the 1999 storm event. Nearby DZO-2 was also heavily impacted,

with 25% of the modern assemblage composed of the brackish species C. halophila and N.

salinarum (Figure 3a). At the time of sampling, these lakes had the highest specific conductivity

and concentrations of major ions, in particular those associated with saline marine waters (i.e. sodium and chloride) (Table 1). The significant change in the diatom assemblages suggests the biology of lakes DZO-29 and DZO-2 were the most heavily impacted by the 1999 storm of the five lakes studied on the outer Mackenzie Delta alluvial plain. Considering both the current specific conductivity and the abundance of brackish diatoms in the remaining systems, the impact of the storm was most severe on Lake DZO-29, followed by DZO-2, DZO-30, DZO-3 and T-34 (Table 1, Figure 2). Based on principal components analysis of the complete data set, following the 1999 storm surge the diatom assemblage in Lake T-34 became more similar to the assemblage observed in the impacted DZO lakes (Figure 4), suggesting a similar response to the stressor of saltwater intrusion. Pearson correlation analyses conducted on the complete 13 lake chemistry data set showed no significant correlations between any of the measured chemical variables (including specific conductivity as a proxy for the impact of the storm surge, and strongly correlated to the abundance of brackish diatoms in the six lakes analyzed (r2 = 0.80, p =

0.03)) and the measured physical variables, including lake area, or estimated distance to the

Beaufort Sea coast (Table 2). This suggests that a combination of variables not easily measured

in this environment, such as catchment area and water residence time, may have played an

important role in modulating the impact of the storm surge on the limnology of these lakes.

Further detailed studies of the characteristics of the study lakes and the details of the storm surge

itself would be required to elucidate the cause of the chemical and biological variation observed.

Nonetheless these data show the impact of this storm was unmatched over the last several

hundred years in all of the lakes studied.

Assessing post-storm surge recovery

A single limnological sample of water chemistry several years after the occurrence of the

storm event, such as were collected here, cannot provide information on possible chemical or

biological recovery. However, detailed palaeolimnological analyses provide the potential for

determining if recovery has occurred (Smol, 2008). In the most heavily impacted sites (DZO-29 and DZO-2), the continued abundance of brackish diatoms representing greater than 25% of the species assemblage in the lakes’ most recent sediment intervals suggests that no recovery has occurred in these systems (Figure 2). Furthermore, our analyses suggest that, while the initial appearance of brackish diatoms occurred at the time of the saltwater inundation, the abundance of these brackish species increased in the years following 1999, possibly as a result of the gradual influx of solutes from the catchment. Soil Na and Cl concentrations in areas impacted by the storm surge have been shown to be over an order of magnitude greater than in unimpacted alluvium (Kokelj et al., 2012), and thus there is the potential for continued enrichment of the lakes with salts from the terrestrial environment. Slight decreases in the abundance of brackish diatoms observed in lakes DZO-30, DZO-3 and T-34 over the last approximately 5 years suggest that very limited chemical recovery may be occurring in these locations (Figure 2), as ions from the catchments and lakes are gradually flushed by annual flooding and precipitation. This process is likely reduced by the fact that freshwater flooding by the Mackenzie River occurs in spring when solutes are trapped by the frozen active layer, and because at this time the lakes remain

capped with ice, preventing their flushing/dilution by floodwaters. In no lake has a return to the

pre-impact diatom assemblage been observed (based on PCA; Figure 4), and thus, while small

decreases in brackish diatom taxa abundances may be related to declining salt concentrations, it

appears that little to no biological recovery to pre-storm surge assemblages has occurred in these

lakes. Southern coastal systems impacted by periodic hurricane activity have recorded relatively

fast recovery rates among algal (Cebrian et al., 2008) and animal (Stevens et al., 2010)

communities following much larger storms, likely as a result of the fact that many southern coastal aquatic ecosystems are brackish or repeatedly exposed to flooding events. The lack of recovery in these freshwater ecosystems a decade after the saltwater inundation illustrates the sensitive nature of these Arctic coastal lakes to episodic flooding by storm surges.

Other diatom assemblage changes

Detailed palaeolimnological analyses of the sediment cores from DZO-2, -3, -30 and T-

34 show that small, benthic, oligohalobian-indifferent Fragilaria taxa (Campeau et al., 1999a,

1999b) dominate the oldest diatom assemblages of these sites (Figure 3). These taxa are able to tolerate a wide range of harsh conditions such as short growing seasons and low light and are found ubiquitously in Arctic lakes (Smol and Douglas, 2007; Smol et al., 2005). In DZO-2,

DZO-3, and DZO-30, located near to each other, increased relative abundances of Navicula cryptocephala and freshwater species of Amphora, inferred to have occurred early in the 20th century, likely resulted from limnological changes associated with climate warming, which is known to have been significant in this region over the period represented by the instrumental

record (Lantz and Kokelj, 2008) and inferred to have begun in the late 19th century based on proxy records (Pisaric et al., 2007). In Lake DZO-29 these changes occur coincident with an

increase in whole lake primary production, inferred from sedimentary reflectance estimates of

trends in chlorophyll a concentrations (Deasley et al., 2012). Increased diatom diversity occurs as a result of longer open-water periods, which allow for the development of more complex periphytic diatom communities. Amphora inariensis, Amphora pediculus, and N. cryptocephala

are common periphytic and epipelic diatoms in many Arctic lakes (Antoniades et al., 2008)

known to colonize plant and sediment substrates in the Tuktoyaktuk coastlands region (Campeau

et al., 1999a), and to be important taxa in lakes of the Mackenzie Delta with little influence from

the river system (Hay et al., 2000). Studies from several regions of the circumpolar Arctic have

shown that warming results in increased diversity (Douglas and Smol, 2010) as diatoms have

longer to colonize habitats previously unavailable under colder climate conditions.

Estimates of the future impacts of anthropogenic climate change predict decreased Arctic

sea-ice extent (Johannessen et al., 2004), increased sea levels in the Arctic Ocean (Nicholls and

Cazenave, 2010), and an increase in the frequency and intensity of Arctic storms (Manson and

Solomon, 2007; Sepp and Jaagus, 2011). Our results suggest there is significant potential for

these changes to result in perturbations to the freshwater ecosystems of the low-lying delta

environments of the circumpolar Arctic, which represent some of the largest deltas on the planet.

These systems represent some of the most unique and fragile delta ecosystems on Earth (Walker,

1998). The salinization of these environments as a result of increased storm-surge activity could

result in major changes to these sensitive systems, which are often considered hot-spots of

diversity and productivity in the Arctic. This threat, coupled with the potential impacts of other

stressors such as hydrocarbon exploration and development, which is increasing in these regions,

must be considered when predicting future changes to the deltaic environments of the

circumpolar Arctic.

Conclusions

Sedimentary diatom assemblages show a synchronous appearance of brackish water taxa coincident with the timing of the large storm surge and resulting saltwater inundation event that

occurred in September of 1999 in this region of the Mackenzie Delta. At no other point in the

history of these lakes (spanning several hundred years) are brackish diatoms found in appreciable numbers, suggesting the impact of this storm surge was unmatched over the recent past. Recent decreases in sea-ice volume in the Beaufort Sea, along with the extreme intensity of the 1999 storm, were likely responsible for the unprecedented impacts observed in these ecosystems. In the most impacted lake, no biological recovery has occurred, and in fact the lakes have exhibited increases in the abundance of brackish taxa as salts likely continue to enter the lake from the impacted/salinized terrestrial environment. In the sites impacted to a lesser extent, slight decreases in brackish species suggest limited chemical recovery may be occurring, but that the systems are still affected over a decade after the 1999 storm. Our research suggests that, for the sensitive coastal freshwater systems of the north, saltwater inundation represents a severe and possibly ecosystem-altering threat, which is predicted to increase as a result of future rapid climate change. Diatom-based palaeolimnological methods are useful for tracking storm-surge events in the Arctic, similar to the approaches used in palaeotempestology for tracking tropical cyclone activity.

Acknowledgements

We thank Courtney Steele and Peter deMontigny for field assistance. We thank MyCore

Scientific Inc. for their work on radiometric dating. We thank members of our labs as well as

three anonymous reviewers for providing helpful comments that improved the quality of the

manuscript. This paper is dedicated to our friend and colleague Steven Solomon, whose passion

and guidance remains instrumental to our work in the Mackenzie Delta, and without whom our

knowledge of the area would be greatly diminished.

Funding

This research was funded by Natural Sciences and Engineering Research Council

(NSERC) of Canada grants to MFJP, JPS and JRT as well as support from the Polar Continental

Shelf Program (PCSP) and the Cumulative Impact Monitoring Program (CIMP).

References

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Chapter 4

Exploratory hydrocarbon drilling impacts to Arctic lake ecosystems

Abstract

Recent attention regarding the impacts of oil and gas exploitation has focused on the

unintentional release of hydrocarbons into the environment, whilst the potential negative effects

of other possible avenues of environmental contamination are often less well documented. In the

hydrocarbon-rich and ecologically sensitive Mackenzie Delta region, saline wastes associated

with hydrocarbon exploration have typically been disposed of in drilling sumps, which are large

pits excavated into the permafrost that were believed to be a permanent containment solution.

However, failure of permafrost as a waste containment medium may cause impacts to lakes in this sensitive environment. Here, we examine the effects of failing drilling sumps on water quality by combining paleolimnological approaches with the analysis of an extensive modern

water chemistry dataset, which includes lakes impacted by saline drilling fluids, lakes with no

visible disturbances, and lakes impacted by significant permafrost thaw slumping. We show that

lakes impacted by drilling sumps have significantly elevated conductivity levels. Chloride levels

are particularly elevated in sump-impacted lakes relative to all other lakes included in the survey.

Paleolimnological analyses showed that invertebrate assemblages have responded to the leaching

of drilling wastes by a discernible increase in a taxon known to be tolerant of elevated

conductivity coincident with the timing of sump construction. With hydrocarbon development in

the north predicted to expand in the coming decades, the use of sumps must be examined in light

of the threat of permafrost thaw, and the potential for these industrial wastes to impact sensitive

Arctic ecosystems.

Keywords: oil and gas development, Arctic, paleolimnology, polycyclic aromatic hydrocarbons,

Cladocera

Introduction

The Mackenzie Delta in Canada’s western Arctic is underlain by significant discovered and

predicted reserves of hydrocarbons (1), but is also amongst the most rapidly warming regions

globally (2). Activities associated with the exploitation of these resources, such as enhanced

exploration and infrastructure development including extraction, production and transmission of

hydrocarbons to market, constitute an additional stressor to the freshwater ecosystems of the

region. The Mackenzie Delta region is ecologically important, as identified by the establishment of the Kendall Island Migratory Bird Sanctuary in 1961, as well as culturally significant for local indigenous communities (3). Much recent attention has focused on oil and gas activities in regards to the delivery of polycyclic aromatic hydrocarbons (PAHs) into the environment (e.g. 4,

5); however the potential effects of industrial activities on aquatic ecosystems are widespread, and PAH contamination is just one example of the environmental consequences of oil and gas development.

Hydrocarbon exploration has been occurring in the Mackenzie Delta region (Fig. 1) since the

1960s, and was particularly intense during the 1970-80s and around 2000 (6). In the Canadian

Arctic, materials associated with the construction of exploratory hydrocarbon wells are disposed of in drilling sumps (Fig. 1; 7). These large pits, excavated into the permafrost near to the location of the exploratory well, are meant to act as a permanent containment location for the wastes associated with exploratory well development, including mud and rock cuttings, and drilling fluids. Drilling fluids are made up of rig wash containing oil, grease, surfactants and detergents, as well as large quantities of highly concentrated saline solutions (primarily potassium chloride, up to 100 g L-1), used as a freezing point depressant during winter drilling

Fig. 1. A) Location of the 101 study lakes in the Mackenzie Delta uplands (Northwest Territories, Canada) (triangles – drilling-sump lakes; squares – thaw-slump lakes; circles – control lakes). Inset shows the region in the context of Canada. B) Image of a failing drilling sump from the Mackenzie Delta uplands, near Parsons Lake, exhibiting significant surface and perimeter ponding. C) Generalized schematic of a drilling mud sump. A large pit is excavated into the permafrost and filled with the drilling wastes and fluids. These drilling fluids are then allowed to partially or completely freeze, and backfilled with the excavated material. The assumption is that the material will be permanently contained in the permafrost. Redrawn from (8).

operations (8-10). Historically, a typical three-kilometre deep well, required to reach the

hydrocarbon reserves in the Mackenzie Delta area, required approximately 40,000 m3 of drilling

fluid alone (7), though this volume has been reduced in more recent operations.

More than 150 drilling sumps have been constructed in the Mackenzie Delta region since the

mid-1960s (6). As most exploration activity occurs in the winter (this practice has been required

by law since 1986 in an attempt to minimize the environmental impact of drilling activities),

these fluids are meant to freeze in situ, and then capped with the material excavated from the

sump. It is assumed the drilling muds are permanently encapsulated within the surrounding

permafrost, and that drilling sumps represent a permanent containment mechanism for materials

associated with hydrocarbon exploration (7).

Recent climate warming has been extensive in the western Canadian Arctic with serious implications for sump containment, as warming is resulting in changes in vegetation

communities and the thaw of near-surface permafrost (3). Ominously, recent studies of sump

integrity have observed increased conductivity beyond the extent of the sump at 74% of the sites

studied (6), and as many as one third of these sites are exhibiting surface ponding, suggesting

significant thaw of the sump contents is occurring (9). In the tundra uplands surrounding the

Mackenzie Delta, migration of potassium chloride through the active layer has been measured

several hundred meters downslope of failing sumps (8).Vegetation communities growing on

sump caps were found to be distinct from surrounding, undisturbed areas, related to factors

including drainage, active-layer depth and soil salt concentrations (10), and these ecological

changes can accelerate warming of the sump and lease areas (11). However, no monitoring

97 information exists on the impacts of saline drilling wastes on nearby freshwater ecosystems. This is particularly important, given that many of the compounds present in drilling muds (e.g. KCl, caustic soda, barite) are known to be toxic to freshwater organisms at the concentrations common in drilling muds (7, 12, 13), and because the majority of the drilling sumps constructed are in the catchments of lakes in this water-rich landscape. Therefore, understanding the effects of drilling sump failure on freshwater in this region is essential.

In this study, we use a combination of modern limnological sampling and inferences of past conditions using material preserved in lake sediments (i.e. paleolimnology) to assess the impacts of drilling fluids on the freshwater ecosystems of the Mackenzie Delta uplands region. We compared contemporary water chemistry measurements of lakes with drilling sumps in their catchments to lakes undergoing another major stressor, intense permafrost degradation in the form of retrogressive thaw slumping, as well as undisturbed control lakes with no evidence of localized disturbance. Retrogressive thaw slumps are a common form of thermokarst, which currently occur on the shoreline of approximately 10% of the lakes in the Mackenzie Delta uplands, and are increasing in size and growth rate as a result of recent warming (14). Thaw slumping is known to result in major changes to lakewater chemistry (15, 16) and biology (17,

18). Because drilling fluids are saline, we hypothesized that if leakage to receiving surface waters is occurring, we should record elevated levels of major ions and conductivity in impacted lakes. We compared lakes with drilling sumps in their catchments to thaw-slump affected lakes in order to put the current limnological conditions in the context of known, highly-disturbed aquatic systems in the region. Due to a lack of long-term biomonitoring data, a variety of sedimentary proxies were analyzed in sediment cores from three lakes (one with a conspicuously

failing drilling sump, experiencing significant surficial ponding, and two control sites) in order to

put the timing and nature of any limnological change in an historical context. We further

hypothesized that if saline-rich wastes from drilling sumps are impacting lakes, we should record

some modest shifts in the assemblages of sentinel biological indicators.

Results and Discussion

The three a priori-defined groups (drilling sump-impacted lakes, permafrost thaw slump-affected

lakes and control lakes) were found to be significantly different based on their modern-day water chemistry (ANOSIM, Global R = 0.307, p = 0.001), and lakes with drilling sumps in their catchments had significantly higher concentrations of potassium (K+) and chloride (Cl-) than either the control lakes or lakes impacted by permafrost thaw slumps (Fig. S1; Table S1). The glaciogenic sediments of the Mackenzie Delta uplands are primarily derived from shale bedrock, and as such are naturally high in sulphate, but relatively low in chloride (19, 20). As a result of permafrost thaw-slump development, the influx of terrestrially-derived materials to lakes results

2- - in a significant difference in SO4 concentration, but no significant difference in Cl concentrations (Table S1). Significantly greater Cl- concentrations in the drilling-sump impacted lakes, therefore, suggests a source other than the underlying geological material, such as the wastes from drilling activity, which in most cases are brine (e.g. KCl) based (7). Based on similarity percentages (SIMPER), Cl- concentrations contributed 19% of the difference between

the drilling-sump and control lakes (more than any other variable), and 13% of the difference

between the drilling-sump and thaw-slump lakes. These results indicate that not only is chloride

elevated in drilling-sump impacted lakes, it is the single most important environmental variable distinguishing sump-impacted lakes from the undisturbed control sites in the region.

Leaching of drilling fluids is clearly the most plausible explanation for the trends in the modern chemical conditions observed in the drilling-sump impacted lakes in this dataset. Lakes impacted by drilling sumps also exhibited significantly higher concentrations of Ca2+, Na+, and specific conductivity compared to the control sites, though significantly less than lakes with thaw slumps

(Fig. S1). Drilling fluids are the most likely source of these ions to impacted lakes, as materials such as caustic soda (NaOH) are common components (12). In addition, as drilling fluids migrate through the active layer downslope to lake ecosystems, other ions present in soils would be translocated to the lake. This impact is exacerbated by the fact that ion-rich permafrost on top of drilling sumps is thawing, and active layer depth is increasing due to enhanced shrub growth

(10), thus liberating base cations, both of which contribute to the leaching of ions into nearby water bodies.

Principal components analysis (PCA) was used to characterize the water chemistry variation in the 101 study lakes, taking into account the combined importance of all measured environmental variables. The first PCA axis primarily represents a response to ionic strength (Fig. 2), which is not surprising given the importance of these variables in accounting for the differences among groups. Lakes impacted by thaw slumps separate from control sites primarily based on these variables (16), while the drilling-sump lakes are more widely distributed within the ordination space (Fig. 2). Some drilling-sump lakes, such as I15, I23A and I17, exhibit environmental conditions similar to sites impacted by large, active permafrost thaw slumps (Fig. 2). Drilling-

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Fig. 2. Principal components analysis (PCA) ordination of select chemical variables in the 101 lake dataset. Black labels represent the position of the drilling-sump lakes in the ordination space (n = 20). Red labels represent lakes impacted by retrogressive thaw slumping (n = 34). Blue labels represent control lake ordination results (n = 47). Variables were all normalized using log transformation. Arrows represent importance of given chemical variables in structuring the distribution of sites. Ordination results of study lakes I20, C23, and C1A, from which sediment cores were analyzed, are circled. Si – reactive silica.

101 sump impacted Lake I15 is chemically most similar to thaw-slump affected Lake 10B, which has an active thaw slump impacting over 25% of the lake’s catchment (15), despite the lack of any natural geomorphic disturbance in Lake I15’s catchment. Other drilling-sump impacted lakes, such as I1 or I12B, are chemically more similar to the control lakes (Fig. 2). Concentrations of major ions and conductivity appear to be a useful tracer for identifying the influx of the various materials from deteriorating drilling sumps into nearby lake ecosystems. The variability in the response of drilling-sump impacted lakes is expected, given the varying degree of sump containment currently observed in the region, with some sumps experiencing significant deterioration while other sites exhibit reasonable to good integrity (9). Exploratory hydrocarbon drilling appears to have resulted in impacts to the freshwater ecosystems of the Mackenzie Delta uplands, in some cases more severe than large-scale, natural, localized geomorphic disturbances, such as retrogressive thaw slump development, which represent a major stressor to these ecosystems.

Due to the lack of long-term biological monitoring data, paleolimnological approaches were used to assess if sump leakage has resulted in any biological changes in sentinel indicator species (21).

Multiple sedimentary proxies were analyzed in radiometrically dated sediment cores from three lakes in the Mackenzie Delta uplands: two sites near Parsons Lake, a location that has undergone significant exploratory hydrocarbon drilling over the last 50 years (6); and one lake approximately 35 km to the south (Fig. 1). One site, I20, is located downslope of a drilling sump that shows evidence of permafrost degradation. The lake shows elevated ionic water concentrations compared to the majority of the control lakes (Fig. 2), suggesting that drilling fluids may be impacting this lake. Two lakes classified as control sites (C23 and C1A) are

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located in close proximity to I20, but with no drilling sumps in their respective catchments. PCA

(Fig. 2) revealed that some control sites, such as Lake C23, exhibited ion concentrations similar to those of some drilling sump-impacted lakes. Because these lakes have no known history of localized disturbance, we hypothesized that the elevated conductivity levels in C23 are natural, and sedimentary indicators in lake sediments should exhibit no change related to sump development. Lake C1A has conductivity levels more typical of control sites (Fig. 2). The analysis of I20 and two control lakes that differ in modern conductivity will allow any changes in the drilling sump-impacted site to be placed in the context of natural chemical variability in the region.

Concentrations of polycyclic aromatic hydrocarbons did not increase following the construction of the drilling sump near Lake I20 (SI text, PAHs). This suggests that, unlike the impact of large- scale extraction operations such as the Alberta oilsands (4, 5), impacts from exploratory drilling activities in this region of the Arctic do not appear related to contamination by hydrocarbons themselves. This is not surprising, given that most drilling in the delta region utilizes brine-based drilling muds. Instead, any environmental impacts of these activities are likely to be related to chemicals present in the drilling fluids, notably salts. Many species of Cladocera (Crustacea,

Branchiopda) are considered poor osmo-regulators, and thus we hypothesized that changes in ionic strength following drilling-sump failure would result in a shift in the species assemblage. In addition there is evidence that potassium chloride in the concentrations found in drilling fluids produces both lethal and sub-lethal effects on Cladocera in laboratory experiments (13).

Cladocera are a key component of aquatic foodwebs, and thus understanding their response to this environmental stressor is essential.

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In Lake I20, an abrupt increase in the relative abundance of Alona circumfimbriata subfossils, a known relatively saline-tolerant cladoceran (22, 23) occurred at the time of sump development in

~1972 (Fig. 3). In a survey of Cladocera in sub-Arctic lakes spanning treeline in the NWT this taxon was most common in the highest conductivity sites (24).While this assemblage change is relatively subtle, the timing and rapid nature of this change occurring at the time of (or very soon after) the construction of the sump, suggests sump disturbance may be primarily related to construction and abandonment practices and not loss of containment over time as a sump slowly fails. No comparable changes in the cladoceran assemblage of either control lake were observed coincident with, or subsequent to, the construction of the sumps near to those sites, despite the natural variability in ion-related water chemistry (Fig. 2). Instead, the primary changes that do occur in the control lakes are gradual and more indicative of the progression of climate change, which has been extensive in this region and has been inferred to be impacting the cladoceran assemblages in another lake in the Mackenzie Delta (25). The increase in A. circumfimbriata is unique when analyzed in the context of the only other regional dataset available for Cladocera in the Canadian sub-Arctic (24) (Fig. 4). Sedimentary diatom assemblages recorded no changes inferred to be as a result of drilling-sump containment loss, and instead are responding to climate warming which has been significant in this region (SI text, Diatoms). The lack of diatom response to changes in lakewater chemistry is not surprising. In lakes impacted by large permafrost thaw slumps, diatom assemblage shifts were inferred to be in response to changes in aquatic habitat, and not chemical changes (18).

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Fig. 3. Stratigraphic profile of the most common cladoceran taxa for lakes A) I20, impacted by drilling sump failure, and control lakes B) C23 and C) C1A. Species assemblages (x axes) are scaled by relative abundance. Down core sedimentary profiles (y axes) are scaled by date, based on 210Pb radiometric dating techniques, with the depth in the sediment core included as a secondary axis. For all three lakes, 2 biostratigraphic zones were identified (constrained incremental sum of squares cluster analysis with the broken stick model) and are plotted with the background colour of one zone in grey the other white. The known timing of construction of the failing drilling sump near Lake I20 (industry ID: Parsons F-09) is included as a horizontal line.

Fig. 4.1:1 plot showing the changes in relative abundance of Alona circumfimbriata between present-day (surface) and pre-industrial (bottom) sediment samples for 50 lakes in the Canadian sub-Arctic. Black circles represent 47 lakes from the only regional cladoceran survey in the Canadian sub-Arctic, spanning modern treeline in the Northwest Territories (24). Blue circles represent the control lakes (C23, C1A) from this study. The red circle represents drilling sump- impacted Lake I20. The 1:1 line is also shown.

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As the sub-Arctic and Arctic continues to warm rapidly, and permafrost temperatures increase,

the likelihood of waste containment issues in drilling mud sumps will increase, resulting in

increased leaching to aquatic ecosystems. Potential climate-induced increases in evaporation, as

have been observed in other high-latitude regions (26, 27), would also lead to reductions in lake

water level, and further concentration of salts. This will be exacerbated by increased ionic flux

due to warming and the thaw of containing permafrost. It is therefore possible that the impacts

inferred from the comparison of modern chemistry and long-term sediment records of these lakes

in the Mackenzie Delta represent as yet a small component of the potential impact of drilling

sumps on lake ecosystems. This is significant due to the fact that to date, at some sites, the

impacts on contemporary limnology have been as large as those associated with spectacular and

conspicuous permafrost degradation. If the contents of drilling sumps, which never adequately

contained the wastes of hydrocarbon exploration, leach into the aquatic system due to a

continued loss of containment following permafrost thaw, the quantity and type of materials

contained in them could result in severe, deleterious impacts on aquatic life. As the scale of

hydrocarbon exploration and development in the Arctic is predicted to increase in the coming decades, it is essential to understand and mitigate the impact of these activities on both the

aquatic and terrestrial ecosystems of this sensitive landscape.

Materials and Methods

101 lakes (20 drilling sump, 34 permafrost slump, and 47 control) in the Mackenzie Delta

uplands (NT, Canada) were sampled for their modern limnological conditions in the summers of

2005 or 2007. Thirteen measured physical and chemical variables were selected and normalized.

Principal components analysis (PCA) was conducted using the vegan package (28) for R (29).

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Analysis of similarity (ANOSIM; 30) and similarity percentages (SIMPER) were conducted

using PRIMER v.6 in order to assess the relationships between the three a priori assigned groups, and to determine the variables that contributed to any dissimilarity. Sediment cores were obtained from lakes I20 (sump-impacted), C23 (control), and C1A (control) (all lake names unofficial) in August 2009 or July 2010 and sectioned at high-resolution. Sediment age determination was conducted following 210Pb radiometric techniques (31). Sedimentary subfossil

indicators were isolated and analyzed using standard techniques (diatoms: (32); cladocerans:

(33)). Relative percentage diagrams were generated using Tilia v.1.7.16 (34). Constrained

incremental sums of squares (CONISS) cluster analyses were conducted in order to identify

biostratigraphic zones of change (35), with the broken stick model used to determine the number

of significant zones (36). Overall lake primary production was estimated by inferring

sedimentary chlorophyll a concentrations via visual reflectance spectroscopy using a FOSS

NIRSystems Model 6500 rapid content analyzer (37). PAHs were extracted from wet sediments

using accelerated solvent extraction (ASE, Dionex). Sulphur compounds and pigments were

removed from the samples using preparative liquid chromatography (Agilent 1100) according to

USEPA method 3640A and fractioned using method 3630C. The fractions containing PAHs

were analyzed using gas chromatography (Agilent 6890) coupled with a mass spectrometer

(Agilent 5973). PAHs and alkyl PAHs were analyzed using single ion monitoring and quantified

using 13C labelled PAHs (Cambridge Isotope Laboratories).

Acknowledgements

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This work was funded by the Natural Sciences and Engineering Research Council (NSERC) of

Canada through Discovery grants to MFJP, JMB and JPS, and an NSERC Northern Supplement to MFJP. The Polar Continental Shelf Program (PCSP) also provided logistical support.

References

1. Dixon J, Morrell GR, Dietrich JR (1994) Petroleum resources of the Mackenzie Delta and Beaufort Sea. Part 1: Basin analysis. Ottawa: Geological Survey of Canada. 2. ACIA (2005) Arctic Climate Impact Assessment. (Cambridge Univ Press, Cambridge, UK). 3. Burn CR, Kokelj SV (2009) The environment and permafrost of the Mackenzie Delta area. Permafrost Periglac Process 20:83-105. 4. Kelly EN, et al. (2009) Oil sands development contributes polycyclicaromatic compounds to the Athabasca Riverand its tributaries. Proc Natl Acad Sci USA 106:22346–22351. 5. Kurek J, Kirk JL, Muir DCG, Wang X, Evans MS, Smol JP (2013) Legacy of a half century of Athabasca oil sands development recorded by lake ecosystems. Proc Natl Acad Sci USA 110:1761-1766. 6. Kanigan J, Kokelj SV (2010) Review of current research on drilling-mud sumps in permafrost terrain, Mackenzie Delta region, NWT, Canada. In: GEO2010: 63rd Canadian Geotechnical Conference & 6th Canadian Permafrost Conference. 6, 1473-1479. 7. French H (1980) Terrain, land use and waste drilling fluid disposal problems, Arctic Canada. Arctic 33:794-806. 8. Dyke LD (2001) Contaminant migration through the permafrost active layer, Mackenzie Delta area, Northwest Territories, Canada. Polar Rec 37:215-228. 9. Jenkins R, Kanigan J, Kokelj SV (2008) Factors contributing to the long-term integrity of drilling-mud sump caps in permafrost terrain, Mackenzie Delta Region, Northwest Territories, Canada. Proceedings of the Ninth International Conference on Permafrost. eds DL Kane, KM Hinkel (University of Alaska Fairbanks Press, Fairbanks, USA) pp 833-843. 10. Johnstone JF, Kokelj SV (2008) Environmental conditions and vegetation recovery at abandoned-drilling mud sumps in the Mackenzie Delta region, NWT, Canada. Arctic 61:199-211. 11. Kokelj SV, Riseborough D, Coutts R, Kanigan JCN (2010) Permafrost and terrain conditions at northern drilling-mud sumps: Impacts of vegetation and climate change and the management implications. Cold Reg Sci Technol 64:46-56. 12. Falk MR, Lawrence MJ (1973) Acute toxicity of petrochemical drilling fluid components and wastes to fish. Ottawa: Fisheries and Marine Services, Environment Canada. 13. Utz L, Bohrer M (2001) Acute and chronic toxicity of potassium chloride (KCl) and potassium acetate (KC2H3O2) to Daphnia similis and Ceriodaphnia dubia (Crustacea; Cladocera). Bull Environ Contam Toxicol 66:379-385. 14. Lantz TC, Kokelj SV (2008) Increasing rates of retrogressive thaw slump activity in the Mackenzie Delta region, N.W.T., Canada. Geophys Res Lett 35:L06502, doi:10.1029/2007GL032433.

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15. Kokelj SV, Jenkins RE, Milburn D, Burn CR, Snow N (2005) The influence of thermokarst disturbance on the water quality of small upland lakes, Mackenzie Delta region, Northwest Territories, Canada. Permafrost Periglac Process 16:343–353. 16. Kokelj SV, Zajdlik B, Thompson MS (2009) The impacts of thawing permafrost on the chemistry of lakes across the subarctic boreal tundra transition, Mackenzie Delta region, Canada. Permafrost Periglac Process 20:185-200. 17. Mesquita PS, Wrona FJ, Prowse TD (2010) Effects of retrogressive permafrost thaw slumping on sediment chemistry and submerged macrophytes in Arctic tundra lakes. Freshw Biol 55:2347-2358. 18. Thienpont JR, et al. (2013) Biological responses to permafrost thaw slumping in Canadian Arctic lakes. Freshw Biol 58:337-353. 19. Rampton VN (1988) Quaternary geology of the Tuktoyaktuk Coastlands, Northwest Territories. Geological Survey of Canada Memoir 423, Energy Mines and Resources Canada, Ottawa. 20. Kokelj SV, Burn CR (2005) Geochemistry of the active layers and near-surface permafrost, Mackenzie delta region, Northwest Territories, Canada. Can J Earth Sci 42:37-48. 21. Smol JP (2008) Pollution of lakes and rivers: A paleoenvironmental perspective, 2nd ed. Wiley-Blackwell. 22. Bos DG, Cumming BF, Smol JP (1999) Cladocera and Anostraca from the Interior Plateau of British Columbia Canada,as paleolimnological indicators of salinity and lake level. Hydrobiologia 392:129–141. 23. Chengalath R (1982) A faunistic and ecological survey of littoral Cladocera of Canada. Can J Zool 60:2668–2682. 24. Sweetman JN, Rühland KM, Smol JP (2010) Environmental and spatial factors influencing the distribution of cladocerans in lakes across the central Canadian Arctic treeline region. J Limnol 69: 76-87. 25. Deasley K, et al. (2012) Investigating the response of Cladocera to a major saltwater intrusion event in an Arctic lake from the outer Mackenzie Delta (NT, Canada). J Paleolimnol 48:287–296. 26. Smol JP, Douglas MSV (2007) From controversy to consensus: making the case for recent climatic change in the Arctic using lake sediments. Front Ecol Environ 5:466-474. 27. Smol JP, Douglas MSV (2007). Crossing the final ecological threshold in high Arctic ponds. Proc Natl Acad Sci USA 104:12395-12397. 28. Oksanen J, et al. (2010) Vegan: Community Ecology Package. R package version 1.17-4. (http://CRAN.R-project.org/package=vegan). 29. R Development Core Team (2010) R: A language and environment for statistical computing. R foundation for Statistical Computing, Vienna, Austria. (http://www.R-project.org). 30. Clarke K (1993) Nonparametric multivariate analyses of changes in community structure. Aust J Ecol 18:117–143. 31. Appleby PG (2001) Tracking Environmental Changes Using Lake Sediments. eds Last WM, Smol JP (Kluwer, Dordrecht, The Netherlands), Vol 1, pp. 171-203. 32. Battarbee RW, et al. (2001) Tracking Environmental Changes Using Lake Sediments. Eds Smol JP, Last WM (Kluwer, Dordrecht, The Netherlands), Vol 3, pp 155-202. 33. Korosi JB, Smol JP (2012) An illustrated guide to the identification of cladoceran subfossils from lake sediments in northeastern North America: part 1—the Daphniidae,

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Leptodoridae, Bosminidae, Polyphemidae, Holopedidae, Sididae,and Macrothricidae. J Paleolimnol 48:571–586. 34. Grimm EC (2011) Tilia v1.6 computer program. Illinois State Museum, Research and Collections Center, Springfield. 35. Grimm EC (1987) CONISS – a FORTRAN-77 program for stratigraphically constrained cluster-analysis by the method of incremental sum of squares. Comput Geosci 13:13-35. 36. Bennett KD (1996) Determination of the number of zones in a biostratigraphical sequence. New Phytol 132:155-170. 37. Michelutti N, et al. (2010) Do spectrally-inferred determinations of chlorophyll a reflect trends in lake trophic status? J Paleolimnol 43:205–217.

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Supplementary Information

Polycyclic Aromatic Hydrocarbons (PAHs)

Sedimentary concentrations of the 12 priority PAHs, including the most common PAHs from

petrogenic sources, did not change at the time of, or subsequent to, drilling sump construction in

any of the three study lakes (Fig. S2). This suggests that, unlike the impact of large-scale

extraction operations such as the Alberta Oilsands (1, 2), impacts from exploratory drilling

activities in this region of the Arctic do not appear related to contamination by hydrocarbons

themselves. This is not surprising, given that these exploratory operations extract comparatively

few hydrocarbons during the process of test well development, and given that relatively high,

stable background PAH concentrations were observed in the sediments of all three lakes

throughout the past few hundred years (Fig. S2).

Supplementary PAH methods:

Wet sediments were homogenized and mixed in an approximate 1:1 ratio with Agilent brand

Hydromatrix©. The samples were spiked with 13C labelled PAHs (Cambridge Isotope

Laboratiories). PAHs were extracted from the wet sediments using accelerated solvent extraction

(ASE, Dionex) at 100˚C with Hexane:Dichloromethane (DCM), followed by

35%Acetone:65%Hexane. The non-polar extract (PAHs, Hexane and DCM) was separated from

the polar extract (water and acetone) by combining the entire sample with DCM, 3% NaCl and

saturated Na2SO4 in a series of liquid-liquid extractions. Sulphur compounds and pigments were removed from the final extract on an Agilent 1100 Preparative Liquid Chromatograph using

Waters Envirogel Columns and USEPA method 3640A. The samples were evaporated to 1ml

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and fractioned, according to USEPA method 3630C, on Davisil 635 silica (60-100 mesh, pore

size 60). The PAH fraction was analyzed by gas chromatography (Agilent 6890) and mass

spectrometry (Agilent 5973). 1µl injections were made in pulsed splitless mode at 280˚C on a

DB-XLB 30m x 0.18µm x 180µm column. An initial oven temperature of 60˚C was held for 2

minutes then increased at a rate of 6˚C per minute to 300˚C and held for 10 minutes. A constant

flow rate of 39cm per second of Helium was used for a total run time of 52 minutes. The mass

spectrometer was set to have a transfer line temperature of 280˚C, with a source temperature of

230˚C and quadrapole temperature of 150˚C.

The following fragments were monitored for PAHs in Single Ion Monitoring (SIM) mode: m/z

128 for naphthalene, m/z 152 for acenapthylene, m/z 153 for acenapthene, m/z 166 for fluorine,

m/z 178 for phenanthrene and anthracene, m/z 202 for fluoranthene and pyrene, m/z 228 for

benz(a)anthracene and chrysene, m/z 240 for chrysene, m/z 252 for benzo(b)fluoranthen,

benzo(k)fluoranthene and benzo(a)pyrene, m/z 278 for indeno(123-cd)pyrene and deibenz(a, h)

anthracene, and m/z 276 for benzo(g,h,i)perylene. Indeno(123-cd)pyrene and

dibenz(a,h)anthracene were combined because or poor peak resolution. Quantification was

performed using 13C labelled PAHs (Cambridge Isotope Laboratories) for all of the compounds

listed above.

The following fragments were monitored for alkylated PAHs in SIM mode: m/z 142 for 1- and

2-Methylnapthalene, m/z 156 for C2-napthalene, m/z 170 for C3-napthalene, m/z184 for C4-

napthalene, m/z 180 for C1-fluorine, m/z194 for C2-fluorine, m/z 208 for C3-fluorine, m/z 192 for C1-phenanthrene and C1-anthracene, m/z 206 for C2-phenanthrene and C2-anthracene, m/z

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220 for C3-phenanthrene and C3-anthracene, m/a 234 for C4-phenanthrene and C4-anthracene,

m/z 216 for C1-fluoranthene and C1-pyrene, m/z 230 for C2-fluoranthene and C2-pyrene, m/z

for 244 for C3-fluroanthene and C3-pyrene, m/z 258 for C4-fluoranthene and C4-pyrene, m/z

242 for C1-benz(a)anthracene and C1-chrysene, m/z 256 for C2-benz(a)anthracene and C2-

chrysene, m/z C3-benz(a)anthracene and C3-chrysene, m/z 266 for C1-benzfluoranthene and C1-

benzopyrene , m/z 280 for C2-benzofluorantene and C2-benzopyrene. Quantification was

performed using 13C labelled non-alkylated PAHs (Cambridge Isotope Laboratories) for all of

the compounds listed above.

Diatoms

Sedimentary diatom assemblages from Lake I20, impacted by a failing drilling sump, do not show any response coincident with, or subsequent to, sump construction (Fig. S3). The primary diatom changes in both I20 and control Lake C23 occur earlier, and consist of an increase in planktonic diatom abundance, indicative of climate warming (3), similar to the response of many other lakes in this region (4). The changes in diatom assemblages in I20 and C23 occur simultaneously with increases in inferred primary production (Fig. S2), suggesting an influence of warming on overall primary production in these lakes. No major changes were observed in the diatom record from C1A, and the inferences of primary production in this lake were below detection limits. The lack of diatom response to changes in lakewater chemistry as a result of drilling sump failure is not surprising as diatoms were found to respond to changes in aquatic habitat, and not chemistry, following the development of large permafrost thaw slumps; systems which our results show have similar chemical compositions.

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References

1. Kelly EN, et al. (2009) Oil sands development contributes polycyclic aromatic compounds to the Athabasca River and its tributaries. Proc Natl Acad Sci USA 106:22346–22351. 2. Kurek J, Kirk JL, Muir DCG, Wang X, Evans MS, Smol JP (2013) Legacy of a half century of Athabasca oil sands development recorded by lake ecosystems. Proc Natl Acad Sci USA 110:1761-1766. 3. Rühland KM, Paterson AM, Smol JP (2008) Hemispheric-scale patterns of climate-induced shifts in planktonic diatoms from North American and European lakes. Global Change Biol 14:2740-2745. 4. Thienpont JR, et al. (2013) Biological responses to permafrost thaw slumping in Canadian Arctic lakes. Freshw Biol 58:337-353.

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Fig.S1. Boxplots of select environmental variables exhibiting significant differences between the a priori defined groups. SU – drilling sump-impacted lakes; CO – control lakes; SL – thaw slump-affected lakes. In each plot, letters indicate significantly different groups (calculated using a Tukey HSD post-hoc test, following ANOVA run on normalized environmental data). Zmax = maximum lake depth.

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Fig. S2. Visual reflectance spectroscopically-inferred chlorophyll a (circles) and summed 12 priority polycyclic aromatic hydrocarbon concentrations (squares) for study lakes A) I20, B) C23 and C) C1A The limit of detection for VRS-chl a is 0.01 mg/g dry weight, and thus the entire C1A profile is below detection.

Fig. S3. Stratigraphic profile of the most common diatom taxa for lakes A) I20, impacted by drilling sump failure, and control lakes B) C23 and C) C1A. Species assemblages (x axes) are scaled by relative abundance. Down core sedimentary profiles (y axes) are scaled by date, based on 210Pb radiometric dating techniques, with the depth in the sediment core included as a secondary axis. For lakes I20 and C23, 2 biostratigraphic zones were identified (constrained incremental sum of squares cluster analysis with the broken stick model) and are plotted with the background colour of one zone in grey the other white. For lake C1A no significant biostratigraphic zones were identified. The known timing of construction of the failing drilling sump near Lake I20 (industry ID: Parsons F-09) is included as a horizontal line.

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Table S1. Summary statistics of water chemistry data for drilling sump lakes, thaw slump- affected lakes and control lakes from the uplands east of the Mackenzie Delta, sampled in the summers of 2005 and 2007.

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Chapter 5

General Discussion and Conclusions

In this thesis I show that sedimentary diatom assemblages in lakes of the Mackenzie

Delta and nearby uplands have undergone a variety of changes as a result of the multiple and interacting stressors impacting the region. The stressors impacting the lakes of the region fall into two broad categories. Firstly, many lakes in the region are being impacted by intense, localized disturbances, including permafrost thaw, saline intrusion and/or impacts from hydrocarbon exploration, which were directly explored in this research program. Secondly, compounding these stressors, lakes are changing as a result of recent climate warming, occurring on a regional scale. Identifying the unique impacts of each stressor, as well as the cumulative impacts to a lake ecosystem, remains a challenge for researchers and lake managers, not just in this region, but globally (Smol 2010).

Regional climate warming has resulted in ecological changes to all of the lakes studied in the Mackenzie Delta region, irrespective of local disturbance status (Chapters 2, 3, 4). The primary mode of response observed in the sedimentary diatom assemblages as a result of recent warming has been an increase in the relative abundance of planktonic diatom taxa, coincident with a decrease in small, benthic fragilarioid species. The degree of this response appears to be related to several factors, although lake depth was an important variable (Chapter 2). A similar response of increased planktonic abundance has been observed in many sub-Arctic lakes in

North America (Rühland et al. 2003, Rühland and Smol 2005) and Europe (Sorvari and Korhola

1998; Sorvari et al. 2002; Solovieva et al. 2005; Solovieva et al. 2008), and represents a trend observed on a hemispheric scale both in high-latitude and temperate regions (Smol et al. 2005;

Rühland et al. 2008). Planktonic taxa are favoured under warmer temperature regimes, as a

118 longer open-ice period (earlier ice-off and later ice-on dates), which also results in a more rapid warming of the water column, which can result in an earlier establishment, longer duration and enhanced strength of thermal stratification and/or stability (Rühland et al. 2010). Empirical studies have shown that these climate-induced changes favour certain diatom species, such as small, centric planktonic taxa, including several Cyclotella species (Fahnenstiel and Glime 1983;

Ptacnik et al. 2003; Winder et al. 2008).

Increases in centric, planktonic taxa represent some of the major changes observed in the diatom assemblages in lakes of the Mackenzie Delta uplands examined in this thesis (Chapter 2,

4). While some lakes showed marked increases in Cyclotella sensu lato taxa, species of the genus Cyclostephanos were also shown to have increased in relative abundance (Chapter 2, 4).

The increase in this taxon likely reflects a similar response to warming as has been observed on a hemispheric scale (Rühland et al. 2008), occurring in lakes with elevated nutrient concentrations

(which were excluded from the Rühland et al. (2008) meta-analysis). Cyclostephanos taxa are often found in lakes with elevated total phosphorus concentrations (Hausmann and Kienast 2006;

Laperièrre et al. 2008), in comparison to Cyclotella species, which are generally found in more oligotrophic waters (Rühland et al. 2010). This highlights the differential response that can occur in response to a similar overriding stressor based on site-specific limnological conditions. In addition, increased relative abundances of pennate planktonic taxa occurred in some lake systems (notable Lake 14a; Chapter 2), a trend that has been observed elsewhere (Solovieva et al. 2008), and further highlights how lake-specific conditions can result in a varied response to regional warming.

Increased planktonic diatom relative abundances in many of the lakes in the Mackenzie

Delta occurred coincident with declines in the relative abundance of benthic fragilarioid species.

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Even in lakes that showed little to no planktonic increase, likely related to their shallow depth not providing conditions favourable for free-floating algae, a decrease in benthic fragilarioid taxa was observed (Chapters 2, 3). This trend was particularly notable in the shallow lakes of the

Mackenzie Delta itself (Chapter 3). These small benthic taxa, found ubiquitously throughout the

Arctic, have been shown to be able to tolerate the challenging conditions in high-latitude lakes, including prolonged periods of ice cover, low-light conditions and cold temperatures (Lotter and

Bigler 2000). Increased temperatures, resulting in an increase in open-water period, thus would favour taxa other than the small, benthic Fragilaria sensu lato species, and explains the near ubiquitous decrease in relative abundances observed in virtually all of the sediment cores analyzed in this thesis (Chapters 2, 3, 4). In the outer Mackenzie Delta, this decrease in benthic fragilarioid taxa occurred subsequent to an increase in overall lake production (inferred from reflectance spectroscopic estimates of chlorophyll a) and changes in cladoceran assemblages that reflect increased open-water secondary production (Chapter 3; Deasley et al. 2012). Similarly, spectroscopically inferred overall production in the reference lakes analyzed in Chapter 2 exhibited increases related to recent warming, coincident with taxon-specific species shifts in both benthic fragilarioid and planktonic diatoms, though a similar trend was not observed in the thaw slump-impacted sites, as a result of dilution due to increased inorganic sedimentation

(Deison et al. 2012).

My data show that intense, localized disturbances are resulting in biological changes in the freshwater ecosystems of the Mackenzie Delta region. Retrogressive thaw slumps, spectacular examples of permafrost degradation found on the shoreline of approximately 10% of the lakes in the ice-rich Mackenzie Delta uplands (Lantz and Kokelj 2008), have resulted in ecologically significant changes to diatom assemblages over the last ~200 years (Chapter 2). One

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of the primary limnological responses to thaw slump development is increased water clarity (as a result of decreased dissolved organic carbon (DOC) concentrations) (Kokelj et al. 2005), which is known to result in significant differences in aquatic macrophyte and moss community development between impacted and reference sites (Mesquita et al. 2010). Increases in the diversity and relative abundances of periphytic diatom taxa, coincident with the known timing of thaw slump development (Chapter 2), suggests that these aquatic habitat changes are important

for structuring diatom communities. One of the interesting features of retrogressive thaw slumps

is their polycyclic nature: new slumps initiate and grow on the lake margin within an area

previously affected by slumping. Slump stabilization occurs as a result of the burying of the ice-

rich headwall, however geomorphic changes, such as rapid lateral talik migration and lake-

bottom subsidence, related to vegetation changes that result in altered ground thermal regimes,

lead to a re-initiation of thaw slump activity at some later date (Kokelj et al. 2009a). As observed

in several lakes in the region, sedimentary diatoms can be useful for inferring the polycyclic

history of slumping in impacted lakes (such as Lake 2b). While only a few sites with ancient

slumps (old stable scars that have never re-initiated) have been identified in the Mackenzie Delta

uplands (Kokelj et al. 2009b), these paleolimnological techniques could be employed to infer

slump histories at these rare sites.

Diatoms are a well-known indicator of changes in salinity (Smol 2008), and have been

used widely for studying past storm activity and storm surges (Horton and Sawai 2010).

Paleotempestology, the study of past cyclonic storm activity using proxy records, has primarily

focused on tracking the frequency of Atlantic hurricanes and Southeast Asian cyclones. As yet,

few studies have been conducted on smaller-scale storm events, resulting in storm surges of less

magnitude, particularly in the Arctic. Diatoms proved to be useful indicators for tracking these

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smaller-scale storms (Chapter 3), and were combined with a variety of other approaches

including remote sensing, local ecological knowledge, dendrochronology, and analysis of

geomorphic samples in order to provide a holistic picture of the impacts of this disturbance

(Kokelj et al. 2012). Paleolimnological analyses were able to show that increased storm surge

activity is strongly related to decreases in sea ice and increases in temperature (Vermaire et al.

2013), and that a particularly large storm in 1999, inferred to have impacted all of the study lakes

from the outer delta analyzed in this thesis (Chapter 3), was unprecedented in at least the last 400

years (Vermaire et al. 2013), though likely the last millennium (Pisaric et al. 2011). The reason

for the unprecedented ecological impact of the 1999 storm is likely related to a variety of factors,

including recent decreases in sea-ice extent and sea-level rise. In addition, the September 1999

storm was particularly intense and was preceded by strong offshore winds which resulted in the

blowing away from shore of the warm, fresh water that sits above the cold, saline water in the

Beaufort estuary. The resultant upwelling brought cold, salty water to the surface, which then

flooded the outer delta as a result of the storm surge brought about by the storm from the

northwest.

Recently, large-scale hydrocarbon exploration operations have received significant

attention for their deleterious impacts to freshwater ecosystems (Kelly et al. 2009, Kurek et al.

2013). However, these studies have focused primarily on the transport (inferred to be occurring

over relatively long ranges) of polycyclic aromatic hydrocarbons (PAHs) to the environment from large emitters, and not on the local impacts on aquatic limnology from smaller hydrocarbon operations. Exploratory hydrocarbon drilling in the Mackenzie Delta region has focused primarily on accessing the significant natural gas deposits in the region. Materials associated with exploratory well construction (such as drilling fluids containing rig wash, cuttings, etc.),

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have been historically deposited in in-ground sumps, which are large pits excavated into the

permafrost. The results of our analyses show that the modern water chemistry in lakes with

sumps in their catchments can vary significantly, with some sites having chemical variables

similar to lakes impacted by large retrogressive thaw slumps (Chapter 4). While sedimentary

diatoms do not appear to have been impacted as a result of leaching of materials from drilling

sumps to freshwater systems, changes in cladoceran assemblages at the time of sump

construction suggest impacts to aquatic biota may be occurring. Importantly, the timing of these

community changes indicates that construction and abandonment techniques may have resulted in deleterious impacts to these aquatic systems.

The results of this thesis illustrate the ongoing challenge in disentangling the impacts of the multiple stressors that are impacting aquatic ecosystems, particularly when they vary on spatial and temporal scales and may be occurring simultaneously. Paleolimnological analyses can provide a long-term perspective on aquatic ecosystem change related to these confounding stressors, and such approaches are particularly effective when used in combination with other techniques such as remote sensing and modern limnological sampling. In the Mackenzie Delta,

the overarching stressor of climate warming has resulted in dramatic and intense localized

disturbances on terrestrial and aquatic environments, which makes this ecologically significant

region a key area for ongoing climate change research. Overall, I believe this thesis provides the

foundation for continued multi-proxy research, and illustrates the effectiveness of

multidisciplinary studies that incorporate paleolimnology for studying a variety of important and emerging stressors in the western Canadian Arctic.

Future Research

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This thesis provides the first evidence for the long-term impact of several important

stressors on the biology of lakes in the Mackenzie Delta region of the western Canadian Arctic.

However, much work remains to be done on the impact of these stressors on freshwater ecosystems. Permafrost thaw was shown to result in ecologically significant changes to the diatom assemblages of lakes in the Mackenzie Delta uplands (Chapter 2); however, to date the impact on higher trophic levels has not been examined. The examination of other biological sedimentary indicators, such as chironomids, and cladocerans, would provide further evidence for the biological response to thaw slumping. By examining the assemblages of these consumers, an assessment of the impact to higher trophic levels could be garnered. This is essential in order to begin to develop a whole-lake understanding of the impact of thaw slumping on lake ecology.

The pan-Arctic assessment of recent environmental changes by Smol et al. (2005), while focussed primarily on diatom-based studies, also incorporated paleolimnological records based on chironomid and Cladocera assemblages. Techniques using constrained ordinations to estimate biological turnover (employed by Smol et al. (2005), and used in Chapter 2 of this thesis) applied to cladoceran and chironomid indicators would not only provide an assessment of the response to thaw slumping, but also to regional climate warming. Preliminary evidence using sedimentary

Cladocera in the Mackenzie Delta region have suggested the cladocerans may be sensitive indicators of climate warming (Chapter 4; Deasley et al. 2012), despite previous studies from more southerly regions which did not show consistent trends related to changes in climate

(Sweetman et al. 2008). The Mackenzie Delta and nearby uplands, as a result of the accelerated warming being experienced there, provide an opportunity for examining the impacts of warming on a variety of aquatic communities.

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In Chapter 3 of this thesis, I present the first evidence for the widespread impacts of a

marine storm surge to lakes in delta ecosystems of the Arctic. This research showed that a recent

storm impacting the Mackenzie Delta was the most severe, in terms of ecological damages, in the last millennium. Because the frequency and intensity of Arctic storms is increasing, coupled with decreasing sea-ice extent and rising sea levels, there is a strong possibility that other low- lying ecosystems have been impacted by saltwater inundation in the circumpolar Arctic. My research has shown diatom-based paleolimnological techniques are effective for tracking saline intrusion into previously freshwater ecosystems. This approach, coupled with remote sensing, such as the use of Landsat imagery (see Appendix A for example), should be applied to other deltaic ecosystems in the circumpolar north, in order to determine whether other systems have been similarly impacted in the recent past.

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Kokelj SV, Jenkins RE, Burn CR, Snow N (2005) The influence of thermokarst disturbance on the water quality of small upland lakes, Mackenzie Delta region, Northwest Territories, Canada. Permafrost and Periglacial Processes, 16, 343-353. Kokelj SV, Lantz TC, Kanigan J, Smith SL, Coutts R (2009a) Origin and polycyclic behaviour of tundra thaw slumps, Mackenzie Delta region, Northwest Territories, Canada. Permafrost and Periglacial Processes, 20, 173-184. Kokelj SV, Zajdlik B, Thompson MS (2009b) The impacts of thawing permafrost on the chemistry of lakes across the subarctic boreal tundra transition, Mackenzie Delta region, Canada. Permafrost and Periglacial Processes, 20, 185-200. Kokelj, SV, Lantz TC, Solomon S, Pisaric MFJ, Keith D, Morse P, Thienpont JR, Smol JP, Esagok D (2012). Utilizing multiple sources of knowledge to investigate northern environmental change: Regional ecological impacts of a storm surge in the outer Mackenzie Delta, N.W.T. Arctic, 65, 257-272. Kurek J, Kirk JL, Muir DCG, Wang X, Evans MS, Smol JP (2013) Legacy of a half century of Athabasca oil sands development recorded by lake ecosystems. Proceedings of the National Academy of Sciences (USA), 110, 1761-1766. Lantz TC, Kokelj SV (2008) Increasing rates of retrogressive thaw slump activity in the Mackenzie Delta region, N.W.T., Canada. Geophysical Research Letters, 35, L06502, doi:10.1029/2007GL032433. Lotter AF, Bigler C (2000) Do diatoms in the Swiss Alps reflect the length of ice-cover? Aquatic Sciences, 62, 125–141. Laperrière L, Fallu M-A, Hausmann S, Pienitz R, Muir D (2008) Paleolimnological evidence of mining and demographic impacts on Lac Dauriat, Schefferville (subarctic Québec, Canada). Journal of Paleolimnology, 40, 309–324. Mesquita PS, Wrona FJ, Prowse TD (2010) Effects of retrogressive permafrost thaw slumping on sediment chemistry and submerged macrophytes in Arctic tundra lakes. Freshwater Biology, 55, 2347-2358. Pisaric MFJ, Thienpont JR, Kokelj SV, Nesbitt H, Lantz TC, Solomon S, Smol JP (2011) Impacts of a recent storm surge on an Arctic delta ecosystem examined in the context of the last millennium. Proceedings of the National Academy of Sciences (USA), 108, 8960- 8965. Ptacnik R, Diehl S, Berger S (2003) Performance of sinking and non-sinking phytoplankton taxa in a gradient of mixing depths. Limnology and Oceanography, 48, 1903–1912. Rühland K, Priesnitz A, Smol JP (2003) Paleolimnological evidence from diatoms for recent environmental changes in 50 lakes across the Canadian Arctic treeline. Arctic, Antarctic, and Alpine Research, 35, 110–123. Rühland K, Smol JP (2005) Diatom shifts as evidence for recent Subarctic warming in a remote tundra lake, NWT, Canada. Palaeogeography, Palaeoclimatology, Palaeoecology, 226, 1–16. Rühland K, Paterson AM, Smol JP (2008) Hemispheric-scale patterns of climate-induced shifts in planktonic diatoms from North American and European lakes. Global Change Biology, 14, 2740-2745. Rühland KM, Paterson AM, Hargan K, Jenkin A, Clark BJ, Smol JP (2010) Reorganization of algal communities in the Lake of the Woods (Ontario, Canada) in response to turn-of-the- century damming and recent warming. Limnology and Oceanography, 55, 2433-2451.

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Smol JP (2008) Pollution of lakes and rivers: A paleoenvironmental perspective, 2nd ed. Wiley- Blackwell. Smol JP (2010) The power of the past: Using sediments to track the effects of multiple stressors on lake ecosystems. Freshwater Biology, 55 (Suppl. 1), 43-59. Smol JP, Wolfe AP, Birks HJB, Douglas MSV, Jones VJ, Korhola A, Pienitz R, Rühland K, Sorvari S, Antoniades D, Brooks SJ, Fallu M, Hughes M, Keatley BE, Laing TE, Michelutti N, Nazarova L, Nyman M, Paterson AM, Perren B, Quinlan R, Rautio M, Saulnier-Talbot E, Siitonen S, Solovieva N, Weckström J (2005) Climate driven regime shifts in the biological communities of Arctic lakes. Proceedings of the National Academy of Sciences USA, 102, 4397-4402. Solovieva N, Jones V, Birks HJB, Appleby P, Nazarova L (2008) Diatom responses to 20th century climate warming in lakes from the northern Urals, Russia. Palaeogeography, Palaeoclimatology, Palaeoecology, 259, 96–106. Solovieva N, Jones VJ, Nazarova L, Brooks SJ, Birks HJB, Grytnes J-A, Appleby PG, Kauppila T, Kondratenok B, Renberg I, Ponomarev V (2005) Palaeolimnological evidence for recent climatic change in lakes from the northern Urals, arctic Russia. Journal of Paleolimnology, 33, 463–482. Sorvari S, Korhola A (1998) Recent diatom assemblage change in subarctic Lake Saanajärvi, NW Finnish Lapland. Journal of Paleolimnology, 20, 205–215. Sorvari S, Korhola A, Thompson R (2002) Lake diatom response to recent Arctic warming in Finnish Lapland. Global Change Biology, 8, 171–181. Sweetman JN, LaFace E, Rühland KM, Smol JP (2008) Evaluating the response of Cladocera to recent environmental change in lakes from the Canadian Arctic treeline region. Arctic, Antarctic and Alpine Research, 40, 584–591. Vermaire JC, Pisaric MFJ, Thienpont JR, Courtney Mustaphi C, Kokelj SV, Smol JP (2013) Arctic climate warming and sea ice declines lead to increased storm surge activity. Geophysical Research Letters, doi: 10.1002/grl.50191. Winder M, Reuter JE, Schladow GS (2008) Lake warming favours small-sized planktonic diatom species. Proceedings of the Royal Society B – Biological Sciences, 276, 427–435.

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Summary

1) Lakes affected by shoreline retrogressive thaw slumping exhibited greater biological

change than paired reference systems, although all systems have undergone ecologically

significant changes over the last ~200 years. This suggests the cumulative impact of

regional warming and intense, localized permafrost thaw represents a more significant

stressor to lake biota than warming alone.

2) The response of sedimentary diatoms to permafrost thaw slumping was understandably

variable, but primarily related to the intensity of permafrost disturbance and associated

changes in aquatic habitat. Five of the slump-affected lakes recorded increases in the

abundance and diversity of periphytic diatoms at the presumed time of slump initiation,

consistent with increased water clarity and subsequent development of aquatic

macrophyte and moss communities.

3) A particularly intense storm originating in the Beaufort Sea in September 1999 resulted

in a large marine storm surge which inundated the low-lying, western, outer Mackenzie

Delta, and resulted in unmatched changes to the freshwater lakes of the region. Lake

sediments record a shift from freshwater to brackish-water taxa coincident with the

timing of the 1999 storm event. The degree of salinization (inferred from the maximum

relative abundance of brackish taxa) was not related to any single modern limnological

variable, such as surface area, depth or distance from the coast. To date, little to no

recovery to pre-impact diatom assemblages has occurred, despite a decade of time since

the inundation.

4) Contemporary limnological conditions in lakes in the vicinity of exploratory hydrocarbon

drilling sumps are significantly different from undisturbed reference sites, and lakes

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impacted by permafrost thaw slumping. In particular these lakes are elevated in

potassium and chloride, which is notable because KCl is often an important component of

drilling fluids.

5) In one lake impacted by a drilling sump with obvious content leakage, sedimentary

Cladocera underwent a notable change coincident with the construction and abandonment

of the sump. The main change in sedimentary diatom assemblages occurred earlier, and

was related to regional climate warming. No similar change in either indicator group was

observed coincident with (or subsequent to) construction of a sump in two nearby control

lakes. This suggests activities related to sump development, construction and / or

abandonment, and not slow failure as a result of regional warming as was originally

predicted, may be responsible for the limnological changes observed.

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Appendix A

Impacts of a recent storm surge on an Arctic delta ecosystem examined in the context of the

last millennium

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Abstract

One of the most ominous predictions related to recent climatic warming is that low-lying coastal environments will be inundated by higher sea levels. The threat is especially acute in

polar regions because reductions in extent and duration of sea ice cover increase the risk of storm surge occurrence. The Mackenzie Delta of northwest Canada is an ecologically significant

ecosystem adapted to freshwater flooding during spring breakup. Marine storm surges during the

open-water season, which move saltwater into the delta, can have major impacts on terrestrial

and aquatic systems. We examined growth rings of alder shrubs (Alnus viridis subsp.

fruticosa) and diatoms preserved in dated lake sediment cores to show that a recent marine storm

surge in 1999 caused widespread ecological changes across a broad extent of the outer

Mackenzie Delta. For example, diatom assemblages record a striking shift from freshwater to brackish species following the inundation event. What is of particular significance is that the

magnitude of this recent ecological impact is unmatched over the >1,000-year history of this lake

ecosystem. We infer that no biological recovery has occurred in this lake, while large areas of

terrestrial vegetation remain dramatically altered over a decade later, suggesting that these

systems may be on a new ecological trajectory. As climate continues to warm and sea ice

declines, similar changes will likely be repeated in other coastal areas of the circumpolar Arctic.

Given the magnitude of ecological changes recorded in this study, such impacts may prove to be

long lasting or possibly irreversible.

Keywords: paleoecology, paleolimnology, dendrochronology, limnology, salinization

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Introduction

Recent climatic warming is predicted to have the most adverse effects on low-lying

coastal environments through inundation by rising sea levels (1). Arctic coastlines are especially

vulnerable (2) due to sea level rise (3), reductions in sea ice extent and duration (4–6), and

increasingly variable storm activity (7, 8). During the 20th century, average global sea level has

risen at a rate of about 1.7–3 mm/y (1) and is expected to rise an additional 0.22 to 0.44 m above

1990 levels by the end of this century (1). As sea level rises, the impacts of storm surge flooding

in low-lying coastal environments will be exacerbated (9). Historical records of climate and

environmental change in many Arctic regions are either nonexistent or of very short duration.

Determining the frequency and magnitude of storm surges using instrumental tidal records is similarly limited by the spatial and temporal extent of these data (10). In the western Canadian

Arctic, the frequency and magnitude of storm surge occurrence have been examined using tidal records from Tuktoyaktuk (1961-present) and log debris lines (10). Traditional knowledge of local indigenous people (the Inuvialuit) suggests an increase in storms that are accompanied by high winds, especially from the east and northwest (11). Coupled with observations of the

Inuvialuit, satellite data confirm that summer sea ice extent has declined nearly 50% between

1978 and 2003 across large portions of the Beaufort Sea (12). The greater extent and seasonal duration of open water, coupled with rising sea levels and more variable storm activity, increase

the vulnerability of low-lying alluvial environments throughout the Arctic to inundation by

marine storm surges. While instrumental records and traditional knowledge are important in

assessing recent storm surge activity, they provide limited insight into the frequency and

magnitude of large-scale storm surge events. Further, instrumental records cannot be used to

determine if recent changes and their ecological impacts are outside the envelope of natural

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variability at centennial to millennial time scales. Understanding the frequency and magnitude of

past storm surge events is critical to predicting ecosystem changes and managing resource development under changing climatic conditions. Here, we present annually resolved dendrochronological records from green alder shrubs (Alnus viridis subsp. fruticosa) and high- resolution, contiguously sampled subfossil diatom records from radiometrically dated lake sediment cores to provide compelling insights into the importance of past storm surge events during the last ~1,000 y in the outer Mackenzie Delta, Northwest Territories, Canada. This region is a wetland of global significance that is underlain by rich hydrocarbon reserves. In particular we focus on a storm surge event that occurred in late September 1999. Our data suggest that saltwater inundations of this magnitude, and the associated ecological impacts, have not occurred in at least the last millennium.

Results and Discussion

To determine the impact, if any, of past storm surges on ecosystems in the outer

Mackenzie Delta, we developed growth-ring chronologies from green alder shrubs growing at varying distances from the coastline (Fig. 1 and Fig. 2A). A total of 107 samples were collected from 10 sites across the study area in 2006 and 2007 (Fig. 1 and Fig. 2B). Chronologies were developed for samples grouped by health status: living healthy, living stressed, or dead. The three chronologies were highly correlated with one another during the common period of overlap

(1950–2003) (Fig. 2A). Although the living healthy shrubs were obtained from areas beyond the apparent extent of the saline incursion during the 1999 storm, they were growing on the alluvial plain and likely were flooded during the storm event. As a result, all three chronologies exhibited an abrupt decrease in ring-width after 1999. Previously known surge events also impacted alder

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Fig. 1. Study area and sites. (A): Study area in the Mackenzie Delta region (solid square). An impacted area defined using changes evident on satellite imagery and field reconnaissance is shown by the dashed line. (B): LANDSAT image (August 2, 1987) of the study area showing the location of alder shrub sampling sites, and lakes C-28 and DZO-29. (C): LANDSAT image (July 18, 2002) showing the large change in reflectance in the impacted zone several years after the 1999 storm surge. Standard Top of Atmosphere corrections were applied to both images, which are displayed using Bands 7, 4, and 2. Apparent differences between the two LANDSAT images are due to changes in water level, and do not reflect increased channel width or redeposition of features following the 1999 storm surge event. The exposed surfaces, such as those near the coast or within some of the channels are sandbars with elevations generally <20 cm. Water levels in the Mackenzie Delta progressively decline during the open-water season, reaching lowest flows in August and September. Thus, differences in the two images reflect these gradual changes in water level during the summer season and the variability between flows in 1987 vs. 2002. Gauge data from Reindeer Station (within ~2 km of DZO-29) recorded water levels of 9.4m on August 2, 1987, and 9.6m on July 18, 2002. Therefore, features that are apparent in the 1987 image were submerged in 2002 and do not suggest that the proximity of Lakes DZO-29 and C-28 changed with respect to the major river channels. Decreased proximity to the channel could have increased their susceptibility to recent storm surges, but our analyses of the LANDSAT images show no significant differences in channel width between the two images.

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growth (Fig. 2A); however, these impacts were of relatively short duration (1–2 y). A major

storm surge in September 1944 predates the instrumental gauge record, but is known from the

accounts of Tuktoyaktuk residents. The dead shrub chronology had a significant decrease in

growth that persisted for approximately 8 y following the 1944 event (Fig. 2A).

In addition to growth declines in alder, large-scale mortality of shrubs also resulted from

the 1999 storm surge (Fig. 2C). Approximately 53% of alder shrub mortality occurred in 1999–

2000. An additional 37% of sampled shrubs died between 2001–2004, reflecting individuals that

were able to survive the initial disturbance event, but then perished in response to changes in

environmental conditions that resulted. A decade later, soils in many impacted areas still have

exceedingly high chloride concentrations, inhibiting the reestablishment of vegetation

communities (Fig. S1).

While the dendrochronological record can be used to assess the terrestrial impacts of

storm surges over the last ~80 y, lake sediments provide a much longer record of past ecosystem

change (13). Lake sediments were collected from two small, closed-basin ponds (DZO-29, C-28;

unofficial names) in the low-lying alluvial plain of the outer Mackenzie Delta (Fig. 1). DZO-29

(69.155694°N, 135.947811°W) is located ~6 km from the coast in the surge impacted zone as

indicated by before and after LANDSAT imagery (Fig. 1) and the relatively high ionic

concentrations of the water (Cl- 5;030 mg/L; Na+ 2;270 mg/L) (Table S1). Lake C-28

(69.082065°N, 134.935284°W) is located ~45 km from the coast, beyond the impacted zone

(Fig. 1) and serves as a control site for our study. C-28 ionic concentrations (Cl- = 7.7 mg/L; Na+

= 6.1 mg/L) were far less than lakes in the impacted zone (Table S1) and are comparable to freshwater lakes sampled away from the coast (14). In both lakes, high-resolution gravity sediment cores were collected in order to sample the lakes’ most recent histories. In addition, in

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Fig. 2. Alder shrub ring-width chronologies and mortality data. (A): Growth chronologies for the living healthy, living stressed, and dead chronologies. Vertical dashed lines represent known open-water season storm surge events with dominant wind direction from the northwest (>6 h in duration and storm surges at least 0.7 m in height) based on the instrumental record from Tuktoyaktuk (2). The 1944 event that predates the instrumental record, but is known from accounts of residents of Tuktoyaktuk, is also indicated. (B): Number of samples in each of the alder shrub growth chronologies through time [line formatting is the same as in (A)]. (C): Alder shrub mortality data as determined by dating dead alder shrubs collected from areas impacted by the 1999 storm surge event.

136 order to obtain a longer-term perspective of marine surge events, a 1.4 m long piston core was recovered from DZO-29. Although the coring procedure for a long core such as this would sacrifice a few centimetres of the surface sediment, the collection of the high-resolution gravity core from DZO-29 provides a combined sedimentary sequence spanning the last millennium. To ensure a complete record of past storm surge impacts, we sampled the gravity and piston cores contiguously at the highest resolution possible for subfossil diatoms (i.e., every sediment sample in the core was analyzed contiguously for diatoms, and so there were no gaps in the sedimentary record).

Diatoms can effectively track past marine intrusions into lacustrine habitats, because these algae are diverse, well preserved, and have well-defined salinity optima (15). The modern diatom assemblage in the high-resolution surface core from DZO-29 is dominated by a combination of brackish water diatom taxa including Craticula halophila, Navicula salinarum, and Navicula crucicula (Fig. 3A). This assemblage reflects the contemporary limnological conditions, which show elevated ionic concentrations in the lake water. These brackish taxa (16–

18) were present in trace abundances throughout the last millennium [as shown in both the surface core (last 2–400 y) and the longer piston core (last thousand years)] (Fig. 3B), as would be expected given the lake’s proximity to the marine environment. Contiguous sampling throughout the entire length of both sediment cores demonstrates that small benthic fragilarioid taxa, which characterize typical freshwater Arctic lakes and ponds (19), dominate the diatom assemblage often approaching 100% relative abundance during much of the last millennium

(Fig. 3 A and B). For a period of time, substantial increases in the abundances of various groups of freshwater, periphytic diatom taxa are observed in the lower half of the piston core from

DZO-29 and represent successional changes of taxa common in other inland delta floodplain

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lakes (20) (Fig. 3B). Nonetheless, the diatom assemblage continues to be composed exclusively

of freshwater taxa. Although the sedimentary sequence obtained from the combined high-

resolution gravity and piston cores from impacted DZO-29 likely encompasses the entire period

since the lake’s inception, the only significant occurrence of saline taxa in the diatom

assemblages occurred in the most recent sediments of the surface core (depth of 2.5 cm and

210Pb-dated to between ~1998 and 2002) (Fig. 3A, Fig. S2), marked by a dramatic and

synchronous shift from once dominant freshwater taxa to an assemblage now dominated by

brackish water taxa. The nature and timing of this major change is consistent with the 1999 storm surge and shows that marine inundation had an immediate and striking ecological impact.

Elevated lake water salinity and continued abundance of brackish water diatom taxa in DZO-29 indicates that closed-basin lakes on the outer alluvial plain have not yet recovered from the 1999 storm surge. In contrast, the diatom assemblages from our control location, C-28, remains unchanged during the 1999 storm surge event (Fig. 3C), and are composed of a diverse group of freshwater taxa similar to those found in other Arctic lakes with no known history of saline

influence (19, 21, 22), including other inland floodplain lakes from this region (20). These

freshwater taxa changes reflect recent warming in this region and across the Arctic (19, 21, 23).

Dynamics of the outer Mackenzie Delta front reflect a balance between sediment supply

and deposition, augmented by deltaic compaction, eustatics, and permafrost aggradation (24).

Variability in the relative importance of these processes through time could alter the position of our study sites relative to the Delta front and make them more/less susceptible to the impacts of

marine storm surges. Permafrost at the Mackenzie Delta front is aggrading upward due to

sediment deposition and alluvial vegetation succession (24), despite recent warming. This

process is expected to continue and outpace deepening of the active layer for at least the next

138

Fig. 3. Stratigraphic profiles showing the relative abundances of the most common diatom taxa. (A): High-resolution surface sediment core from Lake DZO-29 (impacted site), and (B): high- resolution sedimentary intervals from the DZO-29 piston core, which likely dates back to the lake’s formation. Diatom taxa classified as brackish are presented in red, with freshwater taxa identified in green. The age chronology of the gravity core was developed using the unsupported 210Pb activity, which reached background levels at 11-cm, indicating an approximate date of 1876 (Fig. S2). Two calibrated AMS 14C dates provide dating control in the deeper sediments. Gray bars between (A) and (B) indicate the approximate overlap between the gravity and piston cores. Gaps in the DZO-29 piston core record (B) represent intervals in which too few diatom valves were present to provide a statistically robust estimate of the overall species assemblage. Nonetheless, the diatom valves present were all from freshwater groups. (C): Diatom profile showing the relative abundances of the most common taxa from a short (7.5 cm) gravity sediment core from control lake C-28. Background levels of 210Pb activity were estimated based on the activity of 214Bi (Fig. S2). In all three sediment cores, constrained incremental sum of squares cluster analysis (CONISS) results are included.

139 several decades. The majority of alluvial terrain at the Delta front is underlain by permafrost which remains two to three degrees below zero (25). Therefore, we cannot attribute the 1999 event to active layer deepening and surface subsidence. While permafrost is aggrading at the

Delta front, the Delta front is also undergoing a period of transgression and has experienced an estimated 2 m/y of coastal retreat over the past ~40 y (26), while relative sea level rise in the

Beaufort Sea is estimated at 1–3 mm/y during the past 3,000 y (27). In this dynamic environment, the position of DZO-29 and C-28 with respect to the contemporary coastline may have decreased by 1–3 km over the past 1,000 y; a change that would not alter the sensitivity of the lakes to inundation, given that recent storm surges often flood alluvial surfaces within 20 km of the coast.

When assessing why the ecological impacts of the 1999 marine storm surge were so dramatic, it is also important to consider the role of tidal flooding near the Mackenzie Delta front. Hurricane-driven storm surges, combined with high tides, can lead to significant physical and ecological damage in low-lying, hurricane-prone regions. One possibility is that the 1999 marine storm surge was the combination of a very strong storm and an exceptionally high tide.

However, instrumental gauge data indicate that tidal ranges at the Mackenzie Delta front are quite small, normally <0.50 m (27). The data does not support the hypothesis that the 1999 storm surge was the result of an anomalously high tide combined with a powerful storm surge. In fact, many storm surges recorded by water level stations throughout the outer Mackenzie Delta exceed the normal tidal range by a factor of 3–4 times.

As the Arctic warms, sea levels rise, ice cover declines, and the length of the open water season increases, the likelihood and potential impacts of storm surges will be exacerbated in low- lying Arctic coastal environments (3). These changes will impact not only the ecological

140

integrity of Arctic coastal systems, but also the infrastructure and economies of many Arctic coastal communities. In the Mackenzie Delta, increasing exposure to autumn storms and

associated surges as sea ice duration decreases may lead to more frequent saltwater intrusions in an ecosystem adapted to freshwater flooding. The ecological impacts of the 1999 storm surge were not matched over the past millennium. The profound and persistent impact to the terrestrial and aquatic systems suggests that an ecological threshold may have been crossed. Ecological trajectories may now favor saline-tolerant vegetation communities, which are currently rare in the outer Mackenzie Delta (28). The changing ecosystem dynamics in the outer Mackenzie Delta represent complex responses to an emerging stressor. As sea levels rise, storm variability increases, and sea ice extent declines during the 21st century, there exists potential for wide- ranging impacts to sensitive coastal environments throughout the circumpolar Arctic. These marine intrusions will also have significant social impacts, as nearly all Arctic indigenous communities are coastal. These communities will need to be prepared as sea ice cover, sea levels, and the frequency and intensity of storms and marine storm surges become more variable in the

21st century.

Materials and Methods

Cross sections were obtained from green alder shrubs in 2006 and 2007. Samples were prepared using standard dendrochronological methods (29), including visual cross-dating and

measuring using a Velmex tree-ring measuring system attached to an Accurite digital encoder.

Cross-dating was verified using the computer program COFECHA (29) and age-related trends

were removed from raw ring-width series using the program ARSTAN (29) prior to aggregating

141

them into the three mean chronologies which were developed based on the apparent health status

of the individual alder shrubs when they were sampled.

High-resolution surface sediment cores (30) were obtained from lakes DZO-29 (22.5 cm)

and C-28 (7.5 cm) in August of 2009. In May 2010 an additional 1.4 m of sediment was

recovered from Lake DZO-29 using a modified Livingstone piston corer (30). Sediment age

determination for the last ~150 y was determined using 210Pb and 137Cs radiometric dating techniques (31) (Fig. S2). Two accelerator mass spectrometry radiocarbon dates were obtained from plant and wood fragments recovered from the piston core (Table S2). The surface cores were sampled contiguously at 0.25-cm intervals for the top 15 cm, and 0.5-cm intervals below 15 cm. The piston core was sectioned at 0.5-cm intervals and sampling was contiguous, with every sediment sample analyzed. Integrated samples from each contiguous sediment interval (i.e., every sediment sample was analyzed so there are no gaps in the record) were analyzed for sedimentary diatoms following standard methods (32). A minimum of 300 (surface cores) or 100

(piston core) diatom valves were identified and enumerated for each sample. Fewer diatoms were counted in the piston core due to the large number of samples, as every sediment sample was enumerated, a strategy employed in other studies (33). Standard methods were followed (32) to ensure taxa were not underrepresented by this counting strategy.

Acknowledgements

We thank members of our labs, G. Chen, and three anonymous reviewers for comments.

This work was funded by the Natural Sciences and Engineering Research Council (NSERC) of

Canada through Discovery grants to M.F.J.P., T.C.L., J.P.S., and an NSERC Northern

Supplement to M.F.J.P. Additional support was provided by the Cumulative Impact Monitoring

142

Program, Indian and Northern Affairs Canada to M.F.J.P., S.V.K. and T.C.L. The Polar

Continental Shelf Program (PCSP) also provided logistical support to M.F.J.P.

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Supporting Information

Fig. S1. Specific conductivity (A) and soluble chloride concentrations (B) in active layer soils for impacted (n=66) and control sites (n=64) throughout the study area. Box and whisker plots show mean conductivity and soil soluble chloride are significantly higher at impacted sites compared with control sites (T124=9.80, p<0.01; T124=9.43, p<0.01).

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Fig. S2. DZO-29 high-resolution surface gravity core (A) radioisotopic activity including 210Pb, 214Bi, and 137Cs activities and (B) constant rate of supply (CRS) model chronology developed from 210Pb activity. As is common with sediment profiles, the temporal resolution of samples decrease with increasing depth. However, diatoms were sampled contiguously throughout the entire length of the short gravity core (75 sample depths analyzed contiguously throughout the length of the 22.5 cm core) and also for the longer piston core (280 sample depths analyzed contiguously throughout the length of the 140 cm long piston core) to ensure that no past storm surges and their ecological impacts could be missed in our analysis. (C) radioisotopic activity including 210Pb, 214Bi, and 137Cs activities and (D) CRS model chronology from the high- resolution surface core from control lake C-28. Because of the short nature of the C-28 core, background 210Pb was estimated from the activity of 214Bi.

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Table S1. Environmental characteristics and water chemistry data for lakes in the study area.

- -2 2+ 2+ + + Lake Latitude Longitude Lake depth Cl SO4 Ca Mg Na K (oN) (oW) (m) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) DZ0-2 69.182078 135.983081 2 5920 716 244 317 2750 86.1

DZ0-3 69.131689 135.952258 2 1000 89 79.9 67.2 475 14.3

DZ0-4 69.117011 135.897811 1 285 55 56.7 31.4 129 4

DZ0-26 69.233997 135.920689 2 596 70 75.5 52.8 278 10.1

C-27 69.111567 135.3042 3 22.6 20 14.2 10.6 11 1.3

C-28 69.068203 134.914686 2 7.7 34 23.9 11.6 6.1 1

DZ0-29 69.155694 135.947811 4.1 5030 496 251 254 2270 57.5

DZ0-30 69.153469 135.950553 2 2530 208 125 114 1120 26.3

DZ0-31 69.226328 135.791839 1.6 768 106 87.4 63.6 380 9.1

DZ0-32 69.268456 135.740603 1.7 1030 216 75.2 80.9 524 15.9

T-33 69.220772 135.503961 2 57.4 30 28.4 10.4 28.3 1

T-34 69.291267 135.530106 2 120 44 33.3 19 57.8 1.6

DZ0-35 69.255406 135.508494 1 280 50 47.1 27.2 142 4.9

Lakes shaded in grey are control lakes located outside of the impacted region. Lakes designated “T” are located in the transitional area between impacted and control locations. Water samples were collected in August 2009 and analysed at the Taiga Environmental Laboratories in Yellowknife, NWT.

147

Table S2. Radiocarbon dates from the DZO-29 sediment core.

Laboratory number Depth (cm) Material 14C age ± 1 SD Calibrated 1σ range (Cal. AD)

Beta-280644 82.0 Lignified wood from 370 +/- 40 BP 1460 to 1630 terrestrial vegetation

Beta-280645 124.0 Lignified wood from 1050 +/- 40 BP 970 to 1020 terrestrial vegetation

AMS radiocarbon dates were obtained from Beta Analytic, Inc. (Florida, U.S.A.) and were calibrated using the CALIB Rev. 5.0.2 (INTCAL04).

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Appendix B: Raw Count Data

B.1: Lake INV07-2a – Raw Diatom Counts

. frequentissima frequentissima . spp

girdle Achnanthes levanderi levanderi Achnanthes marginestriata Achnanthes marginulata Achnanthes microscopica Achnanthes minutissima Achnanthes pusilla Achnanthes rupestoides Achnanthes subatomoides Achnanthes suchlandtii Achnanthes rossi Achnanthes ventralis Achnanthes Achnanthes Interval (cm) acares Achnanthes chlidanos Achnanthes curtissima Achnanthes didyma Achnanthes digitulus Achnanthes impexiformis Achnanthes kuelbsii Achnanthes lanceolata Achnanthes 0.0-0.25 2 0 4 0 1 0 0 1 0 0 0 0 11 5 0 9 0 1 0 0 0.25-0.5 16 1 1 0 0 1 1 1 5 0 1 0 12 5 0 6 0 0 0 1 0.5-0.75 7 2 2 0 0 3 0 0 2 0 0 7 2 14 0 14 0 0 0 0 0.75-1.0 4 1 5 0 0 2 0 0 2 0 0 7 15 7 0 3 0 0 0 0 1.25-1.5 15 1 3 0 0 1 0 0 0 0 0 3 7 7 0 7 0 0 0 0 1.75-2.0 12 5 5 1 0 1 0 3 2 0 0 5 8 10 2 4 1 0 0 4 2.25-2.5 11 3 8 2 0 0 0 0 2 0 0 5 6 5 0 3 0 0 0 3 2.75-3.0 3 6 4 2 0 0 0 0 8 0 2 4 3 3 0 1 0 0 0 4 3.75-4.0 9 7 9 4 0 0 0 0 7 0 0 3 8 9 0 7 0 0 0 2 4.75-5.0 4 3 7 2 0 0 0 0 7 0 0 3 8 12 0 8 0 0 0 0 5.75-6.0 6 4 3 0 0 0 0 2 13 0 0 2 4 14 0 5 0 0 0 0 6.75-7.0 5 2 2 2 0 4 0 1 2 1 0 1 8 4 0 5 0 0 0 4 7.75-8.0 3 3 6 0 0 1 0 0 3 0 0 3 15 11 0 8 0 0 0 4 8.75-9.0 2 9 2 1 0 1 0 0 2 2 0 1 5 11 0 2 0 0 0 0 9.75-10.0 1 12 5 0 0 0 0 0 0 0 0 0 4 10 0 3 0 0 4 0 10.5-10.75 8 0 8 0 0 1 0 1 0 1 0 2 17 10 0 5 0 0 0 0 11.75-12.0 3 0 7 0 0 0 0 2 0 0 0 2 11 11 0 5 0 0 0 2 13.0-13.25 8 0 5 0 0 2 0 2 1 0 0 1 8 11 0 5 0 0 0 0 14.25-14.5 10 1 4 2 0 0 0 2 0 1 0 3 4 11 0 1 0 0 0 0 15.5-16.0 4 5 5 0 0 0 0 4 0 0 0 0 10 9 0 1 0 0 0 0 17.0-17.5 1 1 1 0 0 0 0 2 0 0 0 0 4 3 0 0 0 0 0 0 18.5-19.0 0 0 6 0 0 0 0 0 3 0 0 0 7 6 0 2 0 0 0 0 20.0-20.5 4 1 8 0 0 0 0 2 0 2 0 0 12 4 0 9 0 0 0 0 21.5-22.0 7 0 7 0 0 0 0 1 6 1 0 2 4 11 0 2 0 0 0 0 23.0-23.5 3 5 4 0 0 0 0 1 0 0 0 0 0 2 0 3 0 0 0 0 24.5-25.0 1 0 1 0 0 0 0 3 3 0 0 2 12 11 0 9 0 0 0 0 26.0-26.5 5 0 4 0 0 1 0 0 6 0 0 2 8 14 0 5 0 0 0 0 27.5-28.0 3 6 10 0 0 2 0 0 7 0 0 4 12 19 0 11 0 0 0 0 29.0-29.5 3 1 5 0 0 2 0 1 6 0 0 0 3 24 0 7 0 0 0 0 30.5-31.0 3 0 5 0 0 0 0 0 10 0 0 2 18 27 0 4 0 0 0 0 32.0-32.5 3 1 4 0 0 1 0 0 5 0 0 1 5 12 0 4 0 0 0 0

149

B.1: Lake INV07-2a – Raw Diatom Counts (cont’d)

euglypta . nivalis var. var

sp. 1 sp. 1 Caloneis bacillum Caloneis bacillum Caloneis Cocconeis placentula lemanica Cyclotella bodanica Cyclotella michiginiana Cyclotella pseudostelligera Cyclotella ocellata Cyclotella stelligera Cyclotella tripartia Cymbella descripta Cymbella gracilis Cymbella herbridica Interval (cm) kriegeriana Amphipleura inariensis Amphora Asterionella formosa distans Aulacoseira Brachysira garrensis Brachysira intermediata Brachysira neoexilis Brachysira 0.0-0.25 0 0 12 1 0 0 0 2 0 0 0 1 0 31 4 3 0 0 0 0 0.25-0.5 0 0 11 0 0 0 0 0 0 0 0 2 3 43 1 3 3 0 0 1 0.5-0.75 0 2 15 0 0 0 0 0 0 0 0 0 3 49 2 2 0 0 0 0 0.75-1.0 0 2 23 0 0 0 0 0 0 0 0 0 2 27 1 2 0 0 0 0 1.25-1.5 0 0 4 1 0 0 0 0 0 0 1 0 1 17 1 0 0 0 1 0 1.75-2.0 0 0 5 2 0 0 0 1 0 0 0 1 0 16 0 1 0 0 0 0 2.25-2.5 0 0 3 5 0 0 0 0 0 0 0 2 2 6 0 0 0 0 0 0 2.75-3.0 0 0 4 2 0 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 3.75-4.0 0 1 2 0 0 0 0 0 0 0 0 3 0 6 0 0 0 0 1 0 4.75-5.0 0 0 1 2 0 0 0 0 0 0 0 6 0 3 0 0 0 0 0 0 5.75-6.0 0 0 1 0 0 0 0 0 0 0 0 4 2 2 0 0 0 0 1 0 6.75-7.0 0 1 0 0 0 0 0 0 0 0 0 8 0 7 0 0 0 0 1 0 7.75-8.0 0 1 2 2 0 0 0 1 0 1 1 0 0 3 0 0 0 0 2 0 8.75-9.0 0 0 4 0 0 0 0 0 0 1 0 0 0 2 1 0 0 0 0 0 9.75-10.0 0 2 7 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 10.5-10.75 0 0 2 0 0 1 0 0 0 0 0 1 0 2 0 0 0 0 1 0 11.75-12.0 0 2 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 0 2 0 13.0-13.25 0 0 5 0 0 0 0 0 0 3 0 6 0 0 0 0 0 0 1 0 14.25-14.5 0 0 2 0 0 0 0 0 0 0 0 5 0 4 0 0 0 0 0 0 15.5-16.0 0 1 0 1 0 2 0 0 0 0 0 4 0 0 0 0 0 0 0 0 17.0-17.5 0 0 0 0 0 0 0 0 0 0 0 15 0 1 0 0 0 0 0 0 18.5-19.0 0 2 3 0 0 0 0 0 0 0 0 2 0 4 0 0 0 0 0 0 20.0-20.5 0 3 1 0 0 0 0 0 0 0 0 13 0 1 0 0 0 0 0 0 21.5-22.0 0 0 5 2 0 0 0 0 0 0 0 3 0 9 0 0 0 0 0 0 23.0-23.5 0 0 2 0 1 0 0 0 0 2 0 7 0 0 0 0 0 0 0 0 24.5-25.0 1 0 2 8 0 0 0 0 0 0 0 18 0 1 1 1 0 0 1 0 26.0-26.5 0 0 2 8 0 0 2 0 0 0 0 5 0 0 0 0 0 0 0 0 27.5-28.0 1 3 3 3 0 0 2 0 0 1 0 2 0 2 0 0 0 0 0 0 29.0-29.5 0 0 2 0 0 0 5 0 0 1 0 1 0 1 0 0 0 0 1 0 30.5-31.0 0 1 0 0 0 0 1 0 0 2 0 8 0 0 0 0 0 0 2 0 32.0-32.5 0 0 6 0 1 0 1 0 2 0 0 2 0 7 0 0 0 0 0 0

150

B.1: Lake INV07-2a – Raw Diatom Counts (cont’d)

papillosa . acularis . . gracilis var var var

girdle Interval (cm) Cymbella incerta Cymbella minuta Cymbella naviculaformis Cymbella subcuspidata Cymbella silesiaca Diploneis boldtiana Diploneis elliptica Diploneis marginestriata Diploneis oblongella Diploneis oculata biulnaris Eunotia exigua Eunotia faba Eunotia Eunotia incisa pirla Eunotia Eunotia brevistriata Fragilaria brevistriata Fragilaria capucina Fragilaria capucina Fragilaria 0.0-0.25 1 0 1 1 0 0 0 0 1 1 0 0 0 0 1 0 5 0 0 0 0.25-0.5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 2 0 0 0.5-0.75 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 5 1 5 0.75-1.0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 9 1 0 6 1.25-1.5 0 1 0 0 0 0 0 0 1 0 0 0 0 1 0 0 13 1 0 5 1.75-2.0 0 2 0 0 0 0 0 1 0 0 2 0 0 0 0 0 10 4 3 3 2.25-2.5 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 12 4 1 1 2.75-3.0 0 1 0 0 0 0 0 0 0 1 0 0 0 1 0 0 24 8 0 1 3.75-4.0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 13 1 1 2 4.75-5.0 1 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 27 11 0 0 5.75-6.0 0 2 0 0 0 0 0 0 0 1 1 0 0 0 0 0 50 7 0 0 6.75-7.0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 55 7 0 0 7.75-8.0 0 2 0 0 0 1 0 0 0 1 0 0 0 1 0 2 38 6 0 0 8.75-9.0 0 3 0 0 0 0 0 0 0 1 0 0 0 4 0 0 31 8 0 0 9.75-10.0 0 1 0 0 0 0 0 0 0 0 0 2 0 0 0 0 42 9 0 4 10.5-10.75 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 36 9 0 1 11.75-12.0 1 2 0 0 0 0 0 0 0 0 0 0 0 2 0 0 42 0 0 0 13.0-13.25 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 51 5 0 2 14.25-14.5 0 4 0 0 0 0 1 0 0 0 0 0 0 0 0 0 29 3 0 0 15.5-16.0 0 1 0 1 0 0 0 0 0 1 0 0 0 0 0 0 40 8 0 0 17.0-17.5 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 1 29 7 0 0 18.5-19.0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 0 0 34 2 0 0 20.0-20.5 0 0 0 2 0 0 0 0 0 1 0 0 0 0 0 0 24 8 0 2 21.5-22.0 0 1 0 1 0 0 1 0 0 3 0 0 0 0 0 2 7 8 0 2 23.0-23.5 0 4 2 0 0 0 0 0 0 0 0 0 0 4 0 0 25 3 0 0 24.5-25.0 1 3 0 0 0 0 0 0 0 0 0 0 0 5 0 0 15 6 0 0 26.0-26.5 0 5 0 1 0 0 0 0 0 0 0 0 0 3 0 0 27 3 0 0 27.5-28.0 0 3 0 0 0 0 0 0 0 1 0 0 0 2 0 0 22 1 0 4 29.0-29.5 0 1 1 0 0 0 0 0 0 0 0 0 4 2 0 0 20 11 0 0 30.5-31.0 0 3 0 0 0 0 0 0 0 0 0 0 1 6 0 0 8 4 0 0 32.0-32.5 0 1 0 0 0 0 0 0 0 0 0 0 2 1 0 0 35 8 0 1

151

B.1: Lake INV07-2a – Raw Diatom Counts (cont’d)

. binodis . pumila . . venter . parasitica . exigua . . rumpens vaucherie . . acuminata . . intercedens . lancettula var var var var var var var Interval (cm) capucina Fragilaria capucina Fragilaria constricta Fragilaria construens Fragilaria var construens Fragilaria var construens Fragilaria var construens Fragilaria neoproducta Fragilaria oldenburgiana Fragilaria parasitica Fragilaria pinnata Fragilaria pinnata Fragilaria pinnata Fragilaria pinnata Fragilaria tenera Fragilaria tenera long Fragilaria Fragilaria virescens crassinerva Frustula Frustulia rhomboides Gomphonema acuminatum 0.0-0.25 0 3 0 0 0 3 87 0 2 4 102 0 6 4 1 0 21 0 0 0 0.25-0.5 0 0 0 0 0 3 85 0 0 0 116 0 10 2 2 1 3 1 0 0 0.5-0.75 0 2 0 0 0 0 138 0 0 2 60 0 0 0 0 2 0 1 0 0 0.75-1.0 0 0 0 0 0 4 117 0 0 0 55 0 17 2 1 0 13 5 0 0 1.25-1.5 0 2 0 3 0 3 92 0 0 2 80 0 14 2 0 0 8 1 0 0 1.75-2.0 1 1 0 0 0 2 98 0 0 0 72 0 8 3 1 0 11 1 0 0 2.25-2.5 0 0 0 0 0 1 114 1 0 0 83 0 18 2 0 0 5 0 0 0 2.75-3.0 0 0 0 2 0 3 128 2 0 0 95 0 17 1 0 0 9 0 0 0 3.75-4.0 0 2 0 0 0 3 125 0 0 0 95 0 17 0 0 0 12 0 0 0 4.75-5.0 0 0 0 0 0 3 97 0 0 0 110 0 10 0 0 0 5 0 0 0 5.75-6.0 0 3 0 0 0 4 94 3 0 0 131 0 11 0 0 0 17 0 0 0 6.75-7.0 0 0 0 0 0 6 81 8 0 0 91 0 14 0 0 0 23 0 0 0 7.75-8.0 0 6 0 0 0 11 85 2 0 0 92 0 19 0 0 0 19 2 0 0 8.75-9.0 0 4 0 6 0 6 48 0 0 0 90 0 14 0 0 0 13 0 0 0 9.75-10.0 0 3 0 0 0 7 84 8 0 0 101 0 29 0 0 0 19 0 0 0 10.5-10.75 0 13 1 0 0 7 103 3 0 4 94 0 28 0 0 0 22 1 0 1 11.75-12.0 0 10 0 16 0 6 104 3 0 0 92 0 7 0 2 0 24 0 0 0 13.0-13.25 0 1 0 10 0 5 80 1 0 0 107 0 23 0 4 0 9 0 1 0 14.25-14.5 0 3 0 4 0 7 81 3 0 0 88 0 12 2 0 0 4 0 0 0 15.5-16.0 0 3 0 0 0 10 69 2 0 0 94 0 11 0 0 0 6 0 0 0 17.0-17.5 0 0 0 0 0 10 59 6 0 0 109 0 9 1 0 0 1 0 0 0 18.5-19.0 0 1 0 0 1 6 60 6 0 0 91 0 19 2 0 0 6 0 0 0 20.0-20.5 0 0 0 0 3 24 60 3 0 0 153 0 22 0 0 0 27 0 0 0 21.5-22.0 0 0 0 0 0 12 76 0 0 2 147 0 16 2 0 0 9 0 0 0 23.0-23.5 0 5 0 0 8 12 51 1 0 2 153 0 21 8 0 0 11 0 0 0 24.5-25.0 0 4 0 0 0 6 56 2 0 2 154 0 27 6 0 0 2 0 0 0 26.0-26.5 0 1 0 0 0 4 63 1 0 0 114 0 11 9 0 0 4 0 0 0 27.5-28.0 0 6 0 0 1 1 52 0 0 0 108 0 10 3 0 0 3 0 0 0 29.0-29.5 0 3 0 4 0 2 47 0 0 0 110 0 10 12 0 0 8 1 0 0 30.5-31.0 0 0 0 0 0 8 47 0 0 0 97 0 7 8 0 0 0 1 0 0 32.0-32.5 1 0 0 3 0 6 55 0 0 2 90 0 7 10 1 0 1 0 0 0

152

B.1: Lake INV07-2a – Raw Diatom Counts (cont’d)

. elliptica Interval (cm) Gomphonema parvulum Gomphonema truncatum Gyrosigma angulatum Navicula circumborealis Navicula cocconeiformis var Navicula cocconeiformis Navicula cryptocephala Navicula cryptotenella Navicula difficillima Navicula digitulus Navicula disjuncta Navicula egregia Navicula expecta Navicula explanata Navicula jaernefeltii Navicula kuelbsii Navicula laevissima Navicula mediocris Navicula pseudoarvensis Navicula pseudoscutiformis 0.0-0.25 2 0 1 0 0 0 2 0 0 0 4 0 0 0 0 2 0 0 1 5 0.25-0.5 1 0 0 0 2 0 3 0 0 0 5 0 0 0 0 4 0 0 1 1 0.5-0.75 1 0 0 0 9 0 1 0 0 0 8 0 0 0 0 0 0 0 8 2 0.75-1.0 0 0 0 0 3 1 7 0 0 0 13 2 0 0 3 4 0 0 2 4 1.25-1.5 2 0 0 0 2 3 3 0 0 0 5 0 0 0 2 5 1 0 4 4 1.75-2.0 0 0 0 0 0 1 4 0 0 0 4 0 0 1 3 1 0 0 2 1 2.25-2.5 1 0 0 0 5 0 3 0 0 0 3 0 0 0 3 1 0 0 3 4 2.75-3.0 0 0 1 0 2 0 1 0 0 0 3 1 0 0 1 4 0 0 1 6 3.75-4.0 0 0 1 0 4 0 3 0 0 0 0 0 0 0 1 5 0 0 0 3 4.75-5.0 2 0 1 0 3 0 0 0 0 0 3 0 1 0 0 1 0 0 0 3 5.75-6.0 3 0 1 0 1 0 1 0 1 0 2 0 0 1 0 2 0 0 0 3 6.75-7.0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 0 0 0 2 7.75-8.0 3 0 0 2 1 0 3 0 0 0 0 0 0 1 0 3 0 0 0 1 8.75-9.0 2 0 0 0 3 0 0 0 0 0 3 0 0 1 1 1 0 0 0 1 9.75-10.0 3 0 0 0 0 0 2 1 0 0 0 0 0 2 0 1 0 0 0 4 10.5-10.75 3 2 0 0 0 0 5 1 0 0 2 0 0 0 0 0 0 0 0 4 11.75-12.0 5 0 0 0 0 0 2 0 0 0 3 0 0 3 2 0 0 0 0 0 13.0-13.25 3 0 1 0 0 0 0 0 0 1 7 0 0 1 0 1 0 0 0 2 14.25-14.5 0 0 5 0 0 0 4 1 3 1 4 0 0 1 1 2 0 1 0 2 15.5-16.0 0 0 3 0 0 0 1 0 0 0 1 0 0 3 0 0 0 0 0 1 17.0-17.5 0 0 18 0 0 0 1 0 0 0 0 0 0 2 0 1 0 0 0 3 18.5-19.0 0 0 1 0 0 0 0 0 0 0 4 0 0 2 1 1 0 1 1 1 20.0-20.5 2 0 0 0 0 0 2 0 0 0 3 0 0 0 0 2 0 0 0 2 21.5-22.0 1 1 13 0 0 0 2 0 0 0 3 0 0 0 0 8 0 0 0 0 23.0-23.5 0 0 2 0 0 0 0 0 0 0 0 0 0 2 1 0 0 0 0 3 24.5-25.0 7 0 2 0 0 0 1 0 0 0 4 0 0 4 0 3 1 0 0 1 26.0-26.5 5 2 0 0 0 0 0 0 0 0 7 0 0 1 2 3 0 0 0 1 27.5-28.0 7 0 0 0 0 0 0 0 0 0 1 0 0 0 0 4 0 0 0 3 29.0-29.5 4 0 0 0 1 0 3 1 0 0 0 0 0 0 0 5 0 0 0 0 30.5-31.0 3 0 0 0 0 0 3 0 0 0 3 0 0 1 1 4 0 1 0 0 32.0-32.5 1 0 9 0 0 0 2 0 0 0 1 0 0 2 1 3 0 0 0 4

153

B.1: Lake INV07-2a – Raw Diatom Counts (cont’d)

. hassiaca . var . pupula var . var . mutata Interval (cm) Navicula pupula Navicula pupula Navicula radiosa Navicula schmassannii Navicula seminulum Navicula soerhensis Navicula submuralis Navicula submuralis Navicula subtillissima Navicula utermoehlii Navicula ventralis Navicula vitiosa Nedium productum Nitzschia palea Nitzschia perminuta Nitzschia tubicola Nitzschia valdestriata balfouriana Pinnularia brauniana Pinnularia gibba Pinnularia interrupta Pinnularia 0.0-0.25 0 3 0 9 3 0 0 0 0 0 3 1 3 0 2 0 7 0 0 0 0.25-0.5 2 0 0 12 0 0 0 0 4 0 10 0 0 0 0 0 3 0 0 2 0.5-0.75 2 0 0 3 0 0 0 0 0 0 9 0 0 0 1 0 7 0 0 0 0.75-1.0 2 0 0 6 6 0 0 0 1 0 8 0 1 8 1 0 8 0 0 0 1.25-1.5 2 1 0 9 7 0 0 1 2 0 9 0 0 11 3 0 15 0 0 0 1.75-2.0 0 2 0 16 8 0 1 0 10 0 13 0 0 10 0 0 24 0 0 0 2.25-2.5 0 0 0 21 6 1 0 0 10 0 6 0 0 0 0 0 16 0 0 0 2.75-3.0 0 0 0 22 12 0 0 0 3 0 15 0 0 2 1 0 5 1 0 0 3.75-4.0 0 0 0 14 3 0 0 0 8 0 14 0 0 5 0 0 0 2 0 0 4.75-5.0 0 0 0 13 0 0 0 0 9 3 15 0 0 3 3 0 2 1 0 0 5.75-6.0 1 0 0 16 5 0 0 0 5 2 24 0 0 2 0 0 0 0 0 0 6.75-7.0 2 0 0 14 3 0 0 0 6 4 17 0 0 0 0 0 1 0 0 0 7.75-8.0 5 1 0 9 7 0 0 0 2 0 26 0 0 2 2 1 1 0 0 0 8.75-9.0 0 0 0 2 9 0 0 0 3 3 7 0 0 3 1 0 1 4 0 0 9.75-10.0 3 0 0 11 2 0 0 0 2 0 8 0 2 0 0 0 1 0 1 0 10.5-10.75 2 0 0 0 5 0 0 0 6 5 14 0 1 2 0 0 0 0 0 0 11.75-12.0 2 0 0 0 0 0 0 0 5 0 8 0 0 0 0 0 0 0 0 0 13.0-13.25 3 1 0 3 3 0 0 0 2 6 12 0 0 2 0 0 0 1 0 0 14.25-14.5 5 0 0 10 4 0 0 0 4 0 11 0 0 5 0 0 4 3 0 0 15.5-16.0 5 0 0 0 1 0 0 0 1 1 3 0 0 0 0 0 0 1 0 0 17.0-17.5 7 3 0 0 0 0 0 0 0 1 6 0 0 1 1 0 1 5 0 0 18.5-19.0 8 0 0 0 3 0 0 0 2 0 3 1 0 1 0 0 0 0 0 0 20.0-20.5 6 0 0 0 13 0 0 0 4 4 4 0 0 1 0 0 1 1 0 0 21.5-22.0 1 0 0 8 4 0 0 0 6 2 13 0 0 4 0 0 1 0 0 0 23.0-23.5 2 0 0 0 1 0 0 0 3 3 8 0 0 0 0 0 0 0 0 0 24.5-25.0 5 0 0 1 2 0 0 0 7 0 17 0 0 0 0 0 0 2 0 0 26.0-26.5 1 0 0 5 4 0 0 0 2 1 28 0 1 1 1 0 0 6 2 0 27.5-28.0 1 0 0 5 1 0 0 0 4 2 16 0 1 2 0 0 0 0 1 0 29.0-29.5 4 0 0 3 4 0 0 0 10 0 20 0 0 5 0 0 0 0 0 0 30.5-31.0 2 0 0 0 1 0 0 0 3 2 20 0 1 0 0 0 0 1 0 0 32.0-32.5 2 0 0 2 4 0 0 0 2 0 14 0 2 0 2 0 1 0 0 0

154

B.1: Lake INV07-2a – Raw Diatom Counts (cont’d)

(IV) Interval (cm) major Pinnularia mesolopta Pinnularia microstaunton Pinnularia nodosa Pinnularia pluviana Pinnularia subgibba Pinnularia girdle Pinnularia anceps Stauroneis phoenocentron Stauroneis Stauroneis smithii Surirella sp. Tabellaria flocculosa Tetracyclus glans Total Chrysophyte Scales Cysts Chrysophyte Phytoliths Plates Protozoan 0.0-0.25 0 0 0 0 0 0 0 6 0 2 0 0 0 388 49 78 0 1 0.25-0.5 0 0 0 1 0 0 0 2 0 0 1 0 0 402 33 92 1 11 0.5-0.75 0 0 1 2 0 0 0 4 0 0 0 0 0 406 35 113 0 6 0.75-1.0 0 0 2 1 0 0 0 5 0 3 0 1 0 427 10 107 2 4 1.25-1.5 0 0 0 0 0 0 2 3 0 1 1 1 0 398 7 85 1 6 1.75-2.0 1 0 0 0 0 0 0 1 0 0 0 1 0 416 12 86 5 5 2.25-2.5 0 2 0 0 0 0 0 4 0 0 0 0 0 410 1 85 1 4 2.75-3.0 0 0 0 0 0 0 0 1 0 0 0 0 0 431 2 58 1 2 3.75-4.0 0 0 0 0 0 0 0 0 0 0 0 4 0 416 6 66 4 3 4.75-5.0 0 0 0 1 0 0 0 2 0 0 0 0 0 394 7 54 10 12 5.75-6.0 0 0 0 0 0 0 0 0 0 1 0 0 0 459 3 87 7 10 6.75-7.0 0 0 0 0 0 0 0 3 0 0 0 1 0 401 2 57 7 11 7.75-8.0 0 0 0 0 0 0 0 0 0 0 0 1 1 427 2 88 11 14 8.75-9.0 0 0 0 0 0 0 0 1 0 0 0 2 1 322 6 82 14 14 9.75-10.0 0 0 2 0 0 0 0 0 0 1 0 0 0 405 3 109 4 13 10.5-10.75 0 0 3 0 2 0 0 4 0 1 2 2 0 451 2 83 6 15 11.75-12.0 0 0 2 0 0 0 0 0 0 2 1 3 0 402 0 93 3 7 13.0-13.25 0 0 3 0 0 1 0 1 0 3 0 0 0 418 2 113 4 5 14.25-14.5 0 0 5 0 0 0 0 4 1 0 1 0 0 371 3 100 7 3 15.5-16.0 0 0 1 0 0 0 0 7 0 2 0 0 0 323 2 53 3 5 17.0-17.5 0 0 1 0 0 0 0 10 0 0 0 2 0 327 0 126 5 8 18.5-19.0 0 0 2 0 0 0 0 3 0 3 0 5 0 310 1 165 2 0 20.0-20.5 0 0 1 0 0 0 2 4 0 0 0 1 0 443 0 173 1 0 21.5-22.0 0 0 0 0 0 0 0 6 0 0 1 0 0 425 7 164 4 0 23.0-23.5 0 0 2 0 0 0 0 0 0 2 0 2 0 367 0 199 2 1 24.5-25.0 0 4 3 4 0 0 0 9 1 0 0 4 0 445 0 170 1 1 26.0-26.5 0 0 5 0 0 0 0 2 1 0 0 2 1 392 0 99 2 3 27.5-28.0 0 2 3 0 0 0 0 8 0 0 1 1 0 375 8 125 0 1 29.0-29.5 0 4 1 4 0 0 2 3 0 0 1 1 1 377 0 164 3 4 30.5-31.0 0 1 2 0 0 1 0 2 0 0 0 3 0 327 1 213 4 1 32.0-32.5 0 0 2 0 0 2 4 3 1 1 0 3 1 351 10 146 2 3

155

B.2: Lake INV07-2b – Raw Diatom Counts

. frequentissima . frequentissima . euglypta . . lemanica. ssp var var Interval (cm) chnanthes curtissima chnanthes curtissima chnanthes acares chnanthes didyma chnanthes impexiformis chnanthes levanderi chnanthes minutissima chnanthes lanceolata chnanthes pusilla chnanthes subatomoides chnanthes suchlandtii chnanthes girdle mphora iariensis mphora libyca mphora ovalis mphora pediculus sterionella formosa Caloneis girdle Caloneis girdle Cocconeis placentula Cyclotella bodanica A A A A A A A A A A A A A A A A Cyclotella comensis 0.0-0.5 0 0 0 0 0 9 0 0 0 0 0 0 0 0 0 0 0 7 0 0 0.5-1.0 0 0 0 0 2 10 0 0 0 0 0 13 0 0 0 0 0 7 0 0 1.0-1.5 0 0 0 0 4 1 0 0 0 0 2 11 0 0 0 6 0 0 0 0 1.5-2.0 0 6 0 0 7 4 0 0 0 0 4 10 0 0 0 16 0 8 0 0 2.5-3.0 0 0 0 0 1 3 0 0 0 0 2 22 0 0 0 24 0 9 0 0 3.5-4.0 0 3 0 0 2 4 1 0 0 0 0 15 0 0 0 14 0 8 0 0 4.5-5.0 0 0 0 0 6 2 0 0 0 0 4 13 0 0 0 22 0 6 0 0 5.5-6.0 8 5 0 0 0 0 1 0 0 5 0 33 2 0 0 5 0 1 0 0 6.5-7.0 6 0 0 1 4 0 0 0 0 4 0 18 7 4 0 6 0 3 1 0 7.5-8.0 14 6 0 0 5 2 0 0 0 11 0 34 3 0 12 3 0 2 0 0 8.5-9.0 19 35 0 0 27 1 0 0 0 1 9 67 2 0 27 7 3 3 0 0 9.5-10.0 13 61 1 0 14 0 4 2 0 67 0 116 9 0 9 0 0 5 0 1 11.0-11.5 21 40 0 0 1 0 0 4 0 28 0 140 0 0 12 2 0 4 0 0 12.5-13.0 6 26 0 0 0 0 0 9 2 18 0 155 0 0 26 0 0 0 0 0 14.0-14.5 12 31 0 0 0 0 0 0 0 16 0 177 0 0 18 0 0 0 0 0 15.5-16.0 8 9 0 0 0 0 0 6 0 8 0 113 0 0 12 0 0 0 0 0 17.0-17.5 0 2 0 0 5 0 0 0 0 0 0 22 0 0 5 0 0 1 0 0 18.5-19.0 0 3 0 0 0 0 0 0 0 0 0 8 2 0 2 0 0 0 0 0 20.0-20.5 2 8 0 0 3 0 0 0 0 6 0 25 4 0 16 0 0 0 0 0 21.5-22.0 3 4 0 0 2 0 1 2 0 5 0 13 3 0 10 0 0 0 0 0 23.0-23.5 0 3 0 0 9 0 0 0 0 6 0 29 2 0 19 0 0 0 0 0 24.5-25.0 2 10 0 0 0 0 0 0 0 5 0 20 1 0 7 3 0 4 0 0 26.0-26.5 0 2 0 0 0 0 0 0 0 0 0 3 0 0 7 0 0 0 0 0 27.5-28.0 0 7 0 0 0 0 0 0 0 6 0 12 0 0 15 0 0 2 0 0 29.0-29.5 0 7 0 0 0 0 0 0 0 2 0 5 0 0 7 0 0 0 0 0 30.5-31.0 0 2 0 0 0 0 0 0 0 3 0 9 0 0 0 0 0 0 1 0 32.0-32.5 0 2 0 0 0 0 0 0 0 2 0 8 1 0 10 0 0 2 0 0 33.0-33.5 0 0 0 0 0 2 0 0 0 2 0 3 0 0 2 0 0 3 0 0

156

B.2: Lake INV07-2b – Raw Diatom Counts (cont’d)

papillosa . pumila . . venter . gracilis var . intercedens var var iatoma tenuis iatoma tenuis iploneis oculata Interval (cm) unotia incisa unotia rhynocephala unotia girdle ragilaria brevistriata ragilaria brevistriata ragilaria capucina ragilaria construens var ragilaria construens var ragilaria construens ragilaria neoproducta ragilaria pinnata ragilaria pinnata D D E E E F F F F F F F F F Cyclotella pseudostelligera Cyclotella pseudostelligera invisitatus Cyclostephanos tholiformis Cyclostephanos Cymbella gracilis Cymbella minuta Cymbella sinuata 0.0-0.5 0 183 79 0 8 0 31 0 0 0 0 0 0 22 0 1 1 0 20 0 0.5-1.0 0 211 78 0 0 0 25 0 0 0 0 0 0 12 0 0 0 0 7 0 1.0-1.5 0 214 104 0 6 0 25 0 0 0 0 0 0 25 0 0 0 0 11 1 1.5-2.0 0 185 78 0 0 0 9 0 0 0 0 3 0 15 0 0 7 0 15 0 2.5-3.0 0 172 44 0 0 0 17 2 0 0 0 0 3 8 0 0 9 0 31 9 3.5-4.0 0 101 71 0 0 0 6 2 0 0 0 0 2 8 0 0 5 0 77 15 4.5-5.0 0 121 43 0 1 0 11 0 0 0 0 14 6 8 0 0 24 0 105 4 5.5-6.0 0 32 16 0 0 0 2 3 0 0 0 0 28 3 0 0 43 0 191 7 6.5-7.0 0 23 14 1 4 4 0 2 0 0 0 1 28 0 0 0 30 0 180 14 7.5-8.0 0 2 3 0 3 0 6 1 0 0 0 0 4 0 0 0 17 0 109 6 8.5-9.0 0 26 18 0 8 0 3 0 0 0 0 0 0 0 0 0 26 0 71 22 9.5-10.0 12 6 6 0 2 0 1 0 0 4 0 0 4 2 0 1 8 5 38 23 11.0-11.5 0 3 3 0 6 0 0 2 3 1 0 2 0 0 0 0 13 2 26 5 12.5-13.0 1 1 1 0 5 0 0 0 0 4 0 0 0 0 0 0 7 0 24 10 14.0-14.5 0 0 0 0 2 0 0 0 1 0 0 4 2 0 13 2 15 0 15 4 15.5-16.0 0 0 3 0 8 0 0 0 0 2 0 0 3 0 0 4 8 0 72 16 17.0-17.5 0 0 1 0 0 0 0 0 0 1 0 7 18 0 4 7 26 0 225 19 18.5-19.0 0 0 0 0 4 0 0 0 0 0 0 3 21 0 0 0 18 0 190 29 20.0-20.5 0 0 0 0 11 0 0 2 0 4 0 2 2 0 1 0 3 0 122 13 21.5-22.0 0 0 0 0 9 0 0 0 0 0 0 1 3 0 0 1 2 0 93 6 23.0-23.5 2 0 0 0 19 0 0 0 0 0 0 0 0 0 0 0 1 0 104 7 24.5-25.0 0 9 6 0 9 0 6 0 0 0 0 6 13 0 5 0 0 0 123 6 26.0-26.5 0 0 0 0 0 0 0 0 0 0 0 6 0 0 3 3 0 0 139 5 27.5-28.0 0 3 4 0 0 0 0 0 0 0 0 2 3 0 4 4 0 0 114 2 29.0-29.5 0 4 1 0 2 0 0 0 0 0 0 3 2 0 0 0 0 0 160 0 30.5-31.0 0 2 4 0 0 0 0 0 0 2 0 0 4 0 0 0 0 0 147 0 32.0-32.5 0 4 3 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 116 0 33.0-33.5 0 1 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 120 0

157

B.2: Lake INV07-2b – Raw Diatom Counts (cont’d)

. exigua . . lancettula var var Interval (cm) avicula cincta avicula cincta avicula cryptocephala avicula difficillima avicula digitulus avicula disjuncta avicula explanata avicula extecta avicula krasskei avicula kuelbsii avicula laevissima avicula notha avicula pupula mutata avicula pupula ragilaria pinnata ragilaria pinnata ragilaria pseudoconstruens ragilaria virescens rustulia crassinerva Gomphonema exiguum Gomphonema exiguum Gomphonema parvulum Gyrosigma angulatum F F F F N N N N N N N N N N N N N 0.0-0.5 0 0 0 0 0 0 0 2 1 0 0 0 0 0 0 0 0 5 4 0 0.5-1.0 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0 0 0 0 0 1.0-1.5 0 0 0 0 0 1 1 0 0 0 0 2 0 0 0 0 0 1 2 0 1.5-2.0 0 0 0 0 0 0 0 4 4 0 0 1 0 0 0 0 0 2 0 0 2.5-3.0 0 0 0 0 0 2 2 7 0 0 0 0 1 0 0 0 0 5 1 0 3.5-4.0 0 0 0 0 0 2 3 0 6 2 0 0 0 0 0 0 0 4 3 0 4.5-5.0 0 0 0 0 0 2 9 4 0 0 0 0 0 0 0 0 0 1 0 0 5.5-6.0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 0 0 0 3 0 6.5-7.0 0 0 0 0 0 1 11 7 0 0 0 0 0 1 0 0 0 7 1 0 7.5-8.0 0 2 3 0 0 0 18 0 5 0 0 1 0 0 0 0 0 5 2 0 8.5-9.0 1 0 0 1 0 2 3 0 4 1 0 0 0 0 1 0 2 4 0 0 9.5-10.0 0 0 0 0 0 0 3 0 3 0 0 0 1 0 0 0 0 0 2 4 11.0-11.5 0 0 0 0 0 1 0 0 1 0 11 0 0 0 0 0 0 0 0 0 12.5-13.0 2 0 0 0 0 0 0 0 1 0 5 0 0 0 0 2 0 0 0 0 14.0-14.5 0 0 2 0 0 0 2 0 0 0 12 0 0 0 0 1 0 0 1 0 15.5-16.0 5 0 0 0 0 1 0 0 1 0 1 0 0 0 0 0 0 0 2 0 17.0-17.5 0 0 0 0 0 0 10 0 3 0 1 1 0 0 0 0 0 0 0 0 18.5-19.0 2 0 0 0 0 0 29 0 1 0 0 0 2 0 0 0 0 0 0 0 20.0-20.5 0 0 0 0 0 0 19 0 0 0 2 0 0 0 0 0 0 0 0 0 21.5-22.0 2 0 0 0 0 2 16 0 2 0 0 0 2 0 0 0 0 0 0 0 23.0-23.5 0 0 0 0 0 0 13 0 0 0 1 0 0 0 0 0 0 0 0 0 24.5-25.0 0 0 2 0 3 0 10 3 1 0 3 0 0 0 0 0 0 0 0 0 26.0-26.5 0 0 0 0 0 0 29 0 0 0 0 0 0 1 0 0 0 0 0 0 27.5-28.0 0 0 0 0 0 0 22 0 0 0 1 0 1 0 0 0 0 0 0 0 29.0-29.5 0 0 0 0 0 0 16 0 0 0 0 0 0 0 0 0 0 0 0 0 30.5-31.0 0 0 0 0 0 0 15 0 0 0 0 0 0 0 0 0 0 0 0 0 32.0-32.5 0 0 0 0 0 0 17 0 0 0 0 0 0 0 0 0 0 0 0 0 33.0-33.5 0 0 0 0 0 0 11 0 0 0 0 0 0 0 0 0 0 0 0 0

158

B.2: Lake INV07-2b – Raw Diatom Counts (cont’d)

r Interval (cm) avicula submuralis avicula submuralis avicula utermoehlii avicula vitiosa 1 avicula sp. avicula girdle itzschia acicularis izschia palea itzschia perminuta innularia majo innularia microstaunton innularia girdle Stauroneis anceps anceps Stauroneis 1 unknown 2 unknown 3 unknown 5 unknown 6 unknown Total Scales Cysts N N N N N N N N P P P 0.0-0.5 0 1 0 0 0 7 3 22 0 0 0 0 0 0 0 0 0 406 2 45 0.5-1.0 0 0 0 0 0 11 4 27 0 0 0 0 0 0 0 0 0 416 0 16 1.0-1.5 0 0 0 0 0 6 3 13 0 0 0 0 0 0 0 0 0 439 0 37 1.5-2.0 0 0 1 0 0 7 6 16 0 0 0 0 0 0 0 0 0 408 0 39 2.5-3.0 10 0 0 0 0 13 3 18 0 0 0 0 0 0 0 0 0 418 0 71 3.5-4.0 5 0 1 0 0 6 2 3 0 0 0 0 0 0 0 0 0 371 1 54 4.5-5.0 7 0 0 0 0 4 2 6 0 0 0 0 0 0 0 0 0 425 0 56 5.5-6.0 1 0 2 0 0 3 0 3 0 0 0 0 0 0 0 0 0 403 0 39 6.5-7.0 0 0 0 0 0 0 0 4 0 0 0 0 4 6 2 0 0 399 0 47 7.5-8.0 0 0 2 7 4 0 0 3 1 0 0 3 0 0 1 0 0 300 0 30 8.5-9.0 16 0 0 0 0 2 2 2 0 0 2 0 0 0 0 0 0 418 0 49 9.5-10.0 2 0 3 0 0 0 0 0 0 0 0 1 0 0 0 14 2 449 0 20 11.0-11.5 18 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 350 0 17 12.5-13.0 23 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 330 2 8 14.0-14.5 13 0 1 0 0 0 0 2 0 0 0 0 0 0 0 0 0 346 0 7 15.5-16.0 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 288 0 13 17.0-17.5 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 359 0 13 18.5-19.0 3 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 319 0 18 20.0-20.5 4 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 250 0 43 21.5-22.0 12 1 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 199 0 42 23.0-23.5 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 220 0 45 24.5-25.0 8 0 0 0 0 0 0 2 0 0 0 1 0 0 0 0 0 268 0 38 26.0-26.5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 198 0 36 27.5-28.0 9 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 214 0 33 29.0-29.5 1 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 212 2 46 30.5-31.0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 190 0 32 32.0-32.5 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 168 0 47 33.0-33.5 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 149 0 48

159

B.2: Lake INV07-2b – Raw Diatom Counts (cont’d)

Interval (cm) Phytoliths Phytoliths Plates Protozoan 0.0-0.5 1 1 0.5-1.0 0 0 1.0-1.5 1 1 1.5-2.0 1 0 2.5-3.0 0 1 3.5-4.0 3 0 4.5-5.0 2 6 5.5-6.0 3 2 6.5-7.0 7 2 7.5-8.0 2 2 8.5-9.0 4 1 9.5-10.0 0 0 11.0-11.5 0 10 12.5-13.0 0 1 14.0-14.5 0 4 15.5-16.0 1 1 17.0-17.5 0 6 18.5-19.0 1 10 20.0-20.5 1 8 21.5-22.0 1 9 23.0-23.5 0 0 24.5-25.0 0 3 26.0-26.5 2 1 27.5-28.0 0 0 29.0-29.5 0 0 30.5-31.0 4 0 32.0-32.5 6 0 33.0-33.5 9 1

160

B.3: Lake INV07-4b – Raw Diatom Counts

. euglypta . . lemanica. var var Interval (cm) acares Achnanthes curtissima Achnanthes exigua Achnanthes gracillima Achnanthes impexiformis Achnanthes lanceolota Acnanthes levanderi Achnanthes minutissima Acnanthes Acnanthes pusilla sp1 Achnanthes sp2 Acnanthes inariensis Amphora libyca Amphora pediculus Amphora ovalis Amphora Caloneis bacillum Cocconeis placentula invisitatus Cyclostephanos Cyclotella bodanica Cyclotella comensis 0.0-0.5 14 1 4 1 0 13 2 3 0 0 0 33 6 1 5 10 6 0 1 5 0.5-1.0 6 0 1 4 0 9 0 3 0 0 0 34 8 0 0 8 0 0 0 2 1.0-1.5 3 0 1 4 0 6 1 1 0 0 0 33 0 0 0 4 0 0 0 1 1.5-2.0 2 0 2 0 0 6 0 2 2 0 0 7 0 0 0 0 0 0 0 0 3.5-4.0 3 0 0 0 0 0 2 0 0 0 0 31 13 0 0 6 0 0 0 0 7.5-8.0 2 0 5 3 4 0 0 3 0 2 2 15 2 1 0 4 5 3 0 0 9.5-10.0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 33.5-34.0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

. papillosa . pumilla . venter var

sp1 Interval (cm) Cyclotella michiginiana Cyclotella pseudostelligera Cyclotella stelligera Cyclotella tripartia Cymbella minuta Cymbella Cymbopleura amphicephala Diploneis elliptica Diploneis oblongella Diploneis oculata Diploneis parma Encyonema gracilis brevistriata Fragilaria brevistriata Fragilaria capucina Fragilaria construens Fragilaria var construens Fragilaria var construens Fragilaria Fragilaria gracilis leptostauron Fragilaria 0.0-0.5 0 24 9 0 0 0 2 12 5 8 19 2 15 32 0 2 0 24 2 0 0.5-1.0 1 9 2 0 0 0 0 11 5 8 15 0 22 23 0 13 1 19 0 0 1.0-1.5 0 4 0 0 0 0 1 6 2 1 8 0 12 43 4 20 2 25 0 0 1.5-2.0 0 5 0 1 0 0 0 0 0 1 12 0 8 13 0 33 0 20 1 1 3.5-4.0 0 0 0 0 1 5 1 5 0 0 2 0 20 28 0 19 0 17 0 0 7.5-8.0 0 2 0 0 0 0 0 3 3 7 10 0 10 8 0 10 0 8 0 6 9.5-10.0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 33.5-34.0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

161

B.3: Lake INV07-4b – Raw Diatom Counts (cont’d)

. menisculus . . intercedens . lancetulla var var var

sp1 Interval (cm) nanana Fragilaria neoproducta Fragilaria pinnata Fragilaria pinnata Fragilaria pinnata Fragilaria Gomphonema parvulum Gyrosigma acuminatum Navicula cincta Navicula cryptocephala Navicula cryptotenella Navicula menisculus Navicula pupula Navicula submuralis Navicula utermoelhii Navicula Nitzschia palea Nitzschia perminuta Nitzschia huge Stauroneis smithii wislouchii Stauroneis 0.0-0.5 1 0 64 9 0 0 11 0 10 10 6 0 3 2 0 12 7 0 0 4 0.5-1.0 0 0 80 12 0 0 21 2 10 0 15 4 3 0 0 9 16 0 1 2 1.0-1.5 0 0 121 19 7 0 44 0 5 0 3 2 1 1 2 3 3 3 0 2 1.5-2.0 0 0 43 6 0 0 19 0 2 0 3 0 1 0 1 0 7 0 0 2 3.5-4.0 0 0 150 76 0 3 28 1 0 0 0 0 0 1 0 0 0 0 0 5 7.5-8.0 0 2 58 0 0 0 15 0 0 0 6 0 0 0 2 8 2 4 2 0 9.5-10.0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 33.5-34.0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Interval (cm) Surirella amphioxys Unknown sp1 sp 2 unknown Unknown sp 3 1 Unknown girdle 2 Unknown girdle valves diatom Total Cysts Chrysophyte 0.0-0.5 0 9 0 3 2 2 416 28 0.5-1.0 1 0 1 1 0 2 384 24 1.0-1.5 2 0 0 0 0 2 402 48 1.5-2.0 0 0 0 0 0 2 202 77 3.5-4.0 2 0 0 0 0 0 419 65 7.5-8.0 0 0 0 0 0 0 217 123 9.5-10.0 0 0 0 0 0 0 0 0 33.5-34.0 0 0 0 0 0 0 0 0

162

B.4: Lake INV07-5a – Raw Diatom Counts

. frequentissima frequentissima . . lemanica. . nivalis spp var var Achnanthes levanderi levanderi Achnanthes marginestriata Achnanthes minutissima Achnanthes pusilla Achnanthes subatomoides Achnanthes inariensis Amphora pediculus Amphora Asterionella formosa distans Aulacoseira Brachysira neoexilis Caloneis bacillum Cocconeis placentula Cyclotella bodanica Interval (cm) acares Achnanthes curtissima Achnanthes didyma Achnanthes exigua Achnanthes impexiformis Achnanthes lanceolota Achnanthes 0 4 2 0 0 0 0 0 0 7 9 5 0 0 53 0 0 2 0 0 0.5 4 0 0 0 0 0 0 0 11 8 2 0 0 40 0 0 2 0 0 1.25 3 0 0 0 2 0 0 0 8 25 12 0 0 31 8 1 4 0 0 2.25 2 4 3 0 0 0 0 0 10 12 8 0 0 23 7 0 4 0 0 2.75 1 7 3 0 1 0 0 0 7 11 13 0 0 8 5 0 2 0 0 3.75 1 0 0 0 0 0 2 0 4 6 5 0 0 24 1 0 1 2 1 5.25 2 0 0 0 0 1 0 0 11 2 1 0 0 7 0 0 0 0 1 6.25 0 0 0 0 0 0 0 0 12 13 3 0 0 43 0 0 0 0 2 8.25 2 0 0 0 0 2 0 0 0 0 1 0 0 2 1 0 0 0 33 10.5 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 16 13 0 0 0 0 0 2 0 0 0 0 0 2 0 0 0 0 0 0 16 15.5 0 0 0 0 0 3 0 0 0 0 1 0 0 0 0 0 1 0 35 18.5 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 21 21.5 0 0 0 0 0 1 0 0 0 0 0 0 0 0 3 0 0 0 22 24.5 0 0 0 0 0 2 0 1 1 0 2 0 0 0 1 3 0 0 37 27.5 0 0 0 0 0 0 0 0 2 2 2 0 0 0 0 0 0 0 22 30.5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 1 0 40 33.5 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 13 36.5 0 0 0 0 0 2 0 0 3 0 0 0 0 0 2 0 0 0 14 39.5 1 0 0 2 0 0 0 1 1 5 0 1 1 0 10 0 0 0 20

163

B.4: Lake INV07-5a – Raw Diatom Counts (cont’d)

. leptostauron leptostauron . . papillosa . venter var . gracilis . rumpens var var var Interval (cm) Cyclotella pseudostelligera Cyclotella stelligera Diploneis oblongella Diploneis oculata Diploneis parma herbridicum Encyonema lunatum Encyonema minuta Encyonema biulnaris Eunotia Eunotia incisa brevistriata Fragilaria brevistriata Fragilaria capucina Fragilaria capucina Fragilaria construens Fragilaria var construens Fragilaria leptostauron Fragilaria leptostauron Fragilaria parasitica Fragilaria 0 180 5 1 0 0 0 0 2 0 0 38 0 14 3 6 15 0 0 0 0.5 120 0 4 0 0 0 1 0 0 2 45 10 14 0 0 20 0 0 0 1.25 56 0 1 1 0 0 1 0 0 2 99 12 6 0 3 20 0 0 0 2.25 37 0 2 4 0 0 0 8 0 0 65 28 6 4 0 23 0 0 2 2.75 29 0 1 6 0 2 0 5 0 0 66 40 5 2 0 19 0 0 2 3.75 21 0 0 0 0 0 0 0 0 0 19 28 8 0 0 10 0 0 1 5.25 8 0 0 0 0 0 1 0 0 5 22 9 7 0 0 9 0 0 0 6.25 54 0 0 0 1 0 0 3 1 3 18 17 10 0 0 2 0 0 0 8.25 0 0 0 0 0 0 0 0 2 2 40 18 0 0 0 25 2 0 0 10.5 0 0 7 8 2 0 0 1 0 1 24 5 0 0 0 21 2 1 0 13 0 0 1 0 0 0 0 0 0 1 20 12 0 0 0 14 0 0 0 15.5 1 0 0 0 0 0 0 1 0 3 10 8 0 0 0 10 0 11 0 18.5 0 0 0 0 0 0 0 0 1 3 25 0 0 0 0 15 0 1 0 21.5 0 0 1 0 0 0 0 1 0 4 24 8 0 0 0 16 5 2 0 24.5 0 0 0 0 0 0 0 0 0 1 30 24 1 0 0 14 14 0 0 27.5 0 0 0 0 0 0 0 0 0 0 44 38 0 0 2 14 11 0 0 30.5 0 0 0 0 0 0 0 0 0 0 21 14 0 0 0 14 0 0 0 33.5 1 0 0 0 0 0 0 2 0 2 23 5 1 0 0 11 4 0 0 36.5 0 0 0 3 0 0 0 0 0 0 33 9 0 0 0 11 1 2 0 39.5 1 0 0 4 0 0 0 0 0 0 25 25 0 0 2 15 5 2 0

164

B.4: Lake INV07-5a – Raw Diatom Counts (cont’d)

. exigua . . intercedens var var Interval (cm) pinnata Fragilaria pinnata Fragilaria pseudoconstruens Fragilaria tenera Fragilaria Fragilaria virescens crassinerva Frustulia Gomphonema parvulum Gyrosigma angulatum Navicula cocconeiformis Navicula cryptocephala Navicula difficillima Navicula disjuncta Navicula expecta Navicula explanata Navicula kuelbsii Navicula mediocris Navicula menisculus Navicula pseudoarvensis Navicula pseudoscutiformis 0 27 4 3 0 0 0 0 0 0 8 4 0 0 0 0 0 0 0 3 0.5 72 6 1 11 0 0 0 0 2 3 3 2 2 0 0 0 0 0 3 1.25 65 6 0 7 0 0 1 0 1 4 3 0 2 0 3 0 0 2 1 2.25 85 6 0 4 2 5 0 0 4 3 0 0 0 0 1 0 3 0 3 2.75 98 9 0 0 3 1 0 0 2 3 0 2 0 0 6 0 0 0 3 3.75 87 11 0 2 0 0 0 3 1 4 0 0 0 0 0 0 0 0 1 5.25 102 4 0 2 1 0 0 5 0 2 0 0 0 0 0 0 0 0 0 6.25 85 2 0 5 14 0 0 2 0 3 0 0 0 0 1 0 0 0 0 8.25 137 13 0 0 3 0 0 6 1 1 0 0 0 0 1 2 0 0 0 10.5 151 7 0 0 0 0 0 1 0 1 0 0 0 0 4 0 0 1 2 13 151 0 0 0 0 0 1 9 0 1 0 0 0 0 0 0 0 0 0 15.5 186 0 0 0 1 0 0 13 0 2 0 0 0 0 0 0 0 0 0 18.5 217 0 0 0 0 0 3 10 0 1 0 0 0 0 0 0 0 0 0 21.5 203 0 0 0 0 0 0 11 0 0 0 0 1 0 0 0 0 0 0 24.5 311 0 0 0 3 0 0 3 0 0 0 2 0 2 0 0 0 0 1 27.5 278 0 0 0 1 0 0 9 0 2 0 0 0 1 0 0 0 0 0 30.5 194 0 0 0 0 0 0 16 0 0 0 0 0 1 0 0 0 0 0 33.5 181 0 0 0 5 0 0 11 0 0 0 0 0 1 0 0 0 0 0 36.5 197 0 0 0 0 0 0 23 0 0 0 0 0 1 0 0 0 0 0 39.5 209 0 0 0 5 0 1 4 0 3 2 0 0 1 1 0 0 0 2

165

B.4: Lake INV07-5a – Raw Diatom Counts (cont’d)

var . mutata pupula var . Interval (cm) Navicula pupula Navicula pupula Navicula radiosa Navicula schmassannii Navicula seminulum Navicula submuralis Navicula utermoehlii Navicula vitiosa Nitzschia palea Nitzschia perminuta Nitzschia tubicola balfouriana Pinnularia borealis Pinnularia brauniana Pinnularia major Pinnularia microstaunton Pinnularia nodosa Pinnularia girdle Pinnularia anceps Stauroneis 0 0 1 0 3 0 2 0 4 9 4 2 0 0 0 0 0 0 0 2 0.5 0 0 0 5 0 0 3 5 4 1 2 0 0 0 0 2 0 0 0 1.25 0 0 0 11 1 0 2 4 8 3 5 0 0 0 0 3 0 0 1 2.25 1 0 3 12 2 0 7 13 7 5 1 1 0 2 0 3 1 0 2 2.75 0 0 2 4 2 0 8 8 6 4 1 0 0 2 0 0 1 2 2 3.75 0 0 0 0 0 0 1 4 0 5 0 2 0 3 0 0 0 0 0 5.25 0 0 0 0 0 0 0 3 2 1 0 0 0 0 0 0 0 0 0 6.25 0 2 0 0 0 0 2 6 1 2 2 0 0 0 0 2 0 0 1 8.25 0 1 3 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 10.5 0 0 0 0 0 0 4 0 4 2 0 0 0 0 23 0 4 0 2 13 0 0 0 0 0 0 2 0 0 2 0 0 0 0 0 0 0 0 1 15.5 0 0 0 0 0 0 2 0 0 0 0 0 0 0 2 0 0 0 0 18.5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 21.5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 24.5 0 0 0 0 0 0 7 7 0 2 0 0 1 0 0 0 0 0 0 27.5 0 0 0 0 0 0 0 4 0 0 0 0 1 0 0 0 0 0 0 30.5 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 33.5 0 0 0 0 0 1 0 2 0 0 0 0 0 0 0 0 0 0 1 36.5 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 1 39.5 0 0 2 0 0 0 2 2 0 0 0 0 0 0 0 0 0 0 0

166

B.4: Lake INV07-5a – Raw Diatom Counts (cont’d)

strain III strain IV Total Diatom Valves Cysts Chrysophyte Chrysophyte Scales Phytoliths Plates Protozoan Interval (cm) phoenicenteron Stauroneis Stauroneis smithii Surirella amphioxys Tabellaria floculosa Tabellaria floculosa 0 0 0 0 0 0 422 155 64 0 0 0.5 0 0 0 0 2 412 137 24 0 0 1.25 2 0 0 0 2 432 147 17 0 2 2.25 0 1 0 0 4 433 181 22 0 2 2.75 0 1 1 0 2 408 160 22 0 2 3.75 0 0 0 0 0 258 149 14 2 5 5.25 0 0 0 0 2 210 67 0 16 2 6.25 0 0 0 2 1 315 83 13 4 0 8.25 0 0 1 0 0 302 149 0 7 0 10.5 3 2 2 0 1 304 248 0 1 0 13 0 0 1 0 0 236 165 0 4 0 15.5 0 0 0 0 5 295 169 0 2 0 18.5 0 0 0 0 0 299 169 0 5 0 21.5 0 0 0 0 1 303 191 1 5 0 24.5 0 0 0 0 2 472 154 0 2 1 27.5 0 0 0 0 0 433 107 0 1 0 30.5 0 0 0 0 0 308 155 0 5 0 33.5 1 0 0 0 2 269 96 0 2 1 36.5 0 0 2 0 2 309 238 0 0 0 39.5 0 0 0 0 0 356 123 0 0 0

167

B.5: Lake INV07-5b – Raw Diatom Counts

. euglypta . . lemanica. . nivalis var var var

sp1 Interval (cm) exigua Achnanthes gracillima Achnanthes levanderi Achnanthes microscopica Achnanthes minutissima Acnanthes petersenii Achnanthes Acnanthes pusilla subatomoides Achnanthes ventralis Achnanthes Achnanthes inariensis Amphora ovalis Amphora distans Aulacoseira Brachysira neoexilis Caloneis bacillum Cocconeis placentula Cyclotella bodanica Cyclotella michiginiana Cyclotella ocellata 0.0-0.2 4 0 0 1 19 3 0 1 0 1 0 0 0 0 0 0 7 25 0 0.4-0.6 3 2 6 0 22 0 2 0 0 2 0 0 0 0 3 0 10 18 0 0.8-1.0 5 0 2 0 4 0 0 0 0 0 0 0 1 1 0 0 1 22 0 1.8-2.0 0 0 0 0 17 0 0 0 0 0 0 2 0 1 3 0 0 11 0 3.0-3.2 4 0 2 0 9 0 2 1 2 0 0 0 4 0 3 0 2 15 1 4.8-5.0 0 0 0 0 0 0 1 0 0 0 0 0 4 0 2 0 1 0 0 6.6-6.8 0 0 0 0 3 0 0 0 0 0 0 0 6 0 0 1 1 1 0 8.4-8.6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 0 0 10.2-10.4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8 0 14.0-14.2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 18.4-18.8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 22.4-22.8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 2 2 0 26.8-27.2 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 30.8-31.2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 34.8-35.2 0 0 0 0 2 0 0 0 0 0 0 0 3 0 0 0 7 0 0

. venter

sp1 Interval (cm) Cyclotella pseudostelligera Cyclotella schumanni Cyclotella stelligera Cymbella minuta Cymbella Cymbopleura amphicephala Diatoma tenuis elongatum Diploneis oculata Diploneis parma biulnaris Eunotia Eunotia incisa brevistriata Fragilaria capucina Fragilaria construens Fragilaria var construens Fragilaria Fragilaria gracilis leptostauron Fragilaria pinnata Fragilaria tenera Fragilaria 0.0-0.2 150 1 25 1 0 3 10 0 0 2 0 15 31 0 5 0 8 76 0 0.4-0.6 95 0 57 0 0 1 4 0 0 0 0 35 14 0 3 1 3 46 0 0.8-1.0 109 0 21 2 0 0 3 0 0 2 0 12 20 0 6 0 10 35 0 1.8-2.0 62 0 8 0 0 0 9 0 0 0 0 47 15 0 0 0 4 55 0 3.0-3.2 38 0 10 0 1 3 5 2 2 4 2 16 18 0 11 0 8 87 2 4.8-5.0 21 0 7 0 2 0 7 0 0 0 4 11 15 0 10 0 8 39 0 6.6-6.8 4 0 0 0 0 0 0 0 0 0 2 38 0 0 11 0 6 103 0 8.4-8.6 0 0 0 0 0 0 0 0 0 0 2 24 4 0 18 0 0 220 0 10.2-10.4 0 0 0 0 4 0 0 0 0 0 0 20 4 0 4 0 0 188 0 14.0-14.2 0 0 0 0 0 0 0 0 0 0 0 15 0 0 7 0 8 208 0 18.4-18.8 0 0 0 0 0 0 0 0 0 0 0 30 0 0 15 0 0 213 0 22.4-22.8 0 0 0 0 0 0 0 0 0 0 0 40 0 2 6 0 0 232 0 26.8-27.2 0 0 0 0 0 0 0 0 0 0 2 36 3 0 9 0 0 150 0 30.8-31.2 0 0 1 0 0 0 0 0 0 1 2 29 0 0 7 0 0 158 0 34.8-35.2 0 0 0 0 0 0 0 0 0 0 0 53 1 0 7 0 12 180 0

168

B.5: Lake INV07-5b – Raw Diatom Counts (cont’d)

. exigua . . hassiaca . var var

notha cf. sp1 Interval (cm) Fragilaria virescens crassinerva Frustulia Gomphonema parvulum Gyrosigma acuminatum Navicula cocconeiformis Navicula cryptocephala Navicula difficillima Navicula disjuncta Navicula laevissima Navicula mediocris Navicula Navicula pupula Navicula radiosa Navicula schmassanni Navicula soehrensis Navicula submuralis Navicula submuralis Navicula utermoelhii Navicula vitiosa Navicula 0.0-0.2 4 0 3 0 1 0 0 1 0 2 7 0 0 0 0 0 0 0 1 0.4-0.6 0 0 0 0 0 9 0 0 1 2 1 0 0 0 1 0 0 10 0 0.8-1.0 4 2 0 1 2 3 1 0 0 0 0 0 0 3 2 5 1 0 0 1.8-2.0 0 0 0 3 2 6 0 0 0 0 0 0 0 0 0 0 1 0 0 3.0-3.2 0 0 1 3 0 10 2 0 0 2 0 0 0 0 2 0 0 0 0 4.8-5.0 0 0 0 11 0 5 0 1 0 0 0 0 1 0 0 0 0 0 0 6.6-6.8 0 0 0 21 0 0 0 0 0 0 0 1 0 0 0 0 0 0 3 8.4-8.6 0 0 0 18 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 10.2-10.4 0 0 0 10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 14.0-14.2 0 0 0 7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 18.4-18.8 0 0 0 12 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 22.4-22.8 0 0 0 12 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 26.8-27.2 0 0 0 20 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 30.8-31.2 0 0 0 9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 34.8-35.2 0 0 0 13 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0

strain IV

huge Interval (cm) Nitzschia acicularis Nitzschia fonticola Nitzschia gracilis Nitzschia lorenziana Nitzschia palea Nitzschia perminuta Nitzschia subacicularis Nitzschia tubicola Nitzschia borealis Pinnularia subgibba Pinnularia phoenicenteron Stauroneis Stauroneis smithii Surirella amphioxys Surirella angusta Surirella barrovcliffa Tabellaria flocculosa Tabellaria quadriseptata 1 Unknown girdle 0.0-0.2 5 8 7 0 17 5 0 0 0 0 0 0 0 0 0 1 0 0 4 0.4-0.6 9 0 6 4 22 20 1 3 0 0 0 0 0 1 3 0 0 0 0 0.8-1.0 6 0 10 4 7 0 0 7 0 0 0 0 4 0 7 0 0 0 0 1.8-2.0 10 0 3 3 14 6 0 5 0 2 0 0 1 0 3 0 0 0 0 3.0-3.2 1 0 5 2 6 3 0 0 0 0 0 1 0 0 0 0 2 0 0 4.8-5.0 2 0 0 0 4 4 0 0 4 0 0 0 0 0 0 0 2 0 0 6.6-6.8 0 0 0 0 0 1 0 0 0 3 0 0 3 0 1 0 3 1 0 8.4-8.6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 10.2-10.4 0 0 0 0 2 2 0 0 0 0 0 0 0 0 0 0 4 0 0 14.0-14.2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 18.4-18.8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 22.4-22.8 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 2 0 0 26.8-27.2 0 0 0 0 0 2 0 0 0 4 0 0 0 0 0 0 0 0 0 30.8-31.2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 34.8-35.2 0 0 0 0 1 0 0 0 0 2 1 0 0 0 0 0 2 0 0

169

B.5: Lake INV07-5b – Raw Diatom Counts (cont’d)

Interval (cm) valves diatom Total Chrysophyte scales Cysts Chrysophyte Phytoliths Plates Protozoan Spicules 0.0-0.2 454 10 101 0 2 0 0.4-0.6 420 18 103 0 5 0 0.8-1.0 325 9 80 0 0 0 1.8-2.0 293 0 136 1 1 0 3.0-3.2 294 8 212 4 2 0 4.8-5.0 166 2 185 3 0 0 6.6-6.8 213 0 285 9 12 6 8.4-8.6 292 8 274 0 0 4 10.2-10.4 246 0 182 0 0 2 14.0-14.2 245 4 245 0 4 2 18.4-18.8 270 0 219 3 3 3 22.4-22.8 304 0 262 0 0 2 26.8-27.2 231 0 159 5 0 2 30.8-31.2 208 0 156 4 8 1 34.8-35.2 285 3 182 2 1 3

170

B.6: Lake INV08-6a – Raw Diatom Counts

. euglypta . var unknown sp1 unknown Interval (cm) acares Achnanthes carissima Achnanthes curtissima Achnanthes impexiformis Achnanthes lanceolota Achnanthes levanderi Achnanthes minutissima Achnanthes pseudoarvensis Achnanthes pusilla Achnanthes subatomoides Achnanthes Achnanthes Amphora libyca libyca Amphora Asterionella formosa Cocconeis placentula Cyclotella pseudostelligera Cyclotella stelligera Cymbella incerta Cymbella naviculiformis Diploneis oculata 0-0.25 19 2 7 5 1 1 5 0 0 12 5 0 10 0 0 0 0 1 1 0.5-0.75 11 1 14 9 0 0 7 1 11 6 0 0 9 1 0 0 1 2 2 1-1.25 18 4 7 0 0 0 4 1 16 13 1 0 7 5 0 0 0 1 2 1.5-1.75 13 2 3 2 2 3 0 0 8 10 0 3 5 0 0 0 0 0 2 2-2.25 12 3 11 2 0 0 2 0 10 5 0 1 6 0 0 0 0 0 1 3-3.25 2 1 10 0 0 0 7 1 5 4 0 2 4 0 0 0 0 0 7 4-4.25 7 0 7 0 3 0 3 0 5 8 0 0 0 0 0 0 0 0 0 5-5.25 11 0 8 2 1 0 4 0 7 5 0 0 2 0 0 0 1 2 1 6-6.25 18 0 6 2 4 1 6 0 8 2 0 1 0 0 0 1 0 0 0 7-7.25 16 0 6 0 2 3 24 0 6 5 0 0 0 8 1 0 1 2 1 8-8.25 13 0 6 0 0 1 26 0 13 2 0 1 0 0 0 0 0 0 2 9-9.25 11 0 8 0 1 0 25 0 10 3 0 0 0 0 0 0 0 0 1 10-10.25 3 0 6 0 2 0 17 0 5 8 0 1 0 1 1 0 0 2 0 12-12.25 12 0 8 0 0 0 16 0 0 6 0 0 0 0 0 0 0 0 0 14-14.25 8 4 8 0 12 0 16 0 10 10 0 0 2 0 0 0 0 0 0 16-16.5 14 0 0 0 0 0 12 0 0 0 0 0 4 2 0 0 0 0 0 18-18.5 12 0 6 2 0 0 12 0 4 0 0 0 0 0 0 0 0 0 0 20-20.5 6 0 4 0 0 0 14 0 0 0 0 0 0 0 0 0 0 0 0 24-24.5 16 0 0 0 0 0 14 0 0 0 0 3 0 0 0 0 0 0 0

171

B.6: Lake INV08-6a – Raw Diatom Counts (cont’d)

venter exigua v.

sp1 sp1 Fragilaria capucina capucina Fragilaria brevistriata Fragilaria construens Fragilaria v. construens Fragilaria neoproducta Fragilaria pinnata Fragilaria Fragilaria virescens Gomphonema acuminatum Gomphonema angustatum Gomphonema parvulum Gyrosigma acuminatum Interval (cm) Diploneis parma herbridicum Encyonema lunatum Encyonema minutum Encyonema Epithemia faba Eunotia Eunotia incisa Eunotia 0-0.25 0 0 0 0 0 0 5 0 2 4 0 83 0 54 24 0 0 0 2 0.5-0.75 0 1 0 1 0 0 7 2 7 7 0 69 0 50 6 0 0 0 0 1-1.25 1 1 0 0 0 0 1 1 0 10 3 73 0 67 9 0 0 4 0 1.5-1.75 0 4 0 0 0 1 0 0 2 6 0 88 0 61 9 0 1 0 0 2-2.25 0 0 0 0 0 6 0 3 0 0 0 82 0 60 3 4 1 0 0 3-3.25 0 0 0 0 0 0 0 1 2 4 0 90 0 100 5 0 0 1 0 4-4.25 0 1 0 0 0 0 0 0 2 0 0 113 0 111 12 0 0 1 1 5-5.25 0 0 0 0 0 0 0 0 0 22 0 115 0 94 2 0 0 3 0 6-6.25 0 0 0 0 0 0 1 0 0 5 0 107 0 103 6 0 0 4 2 7-7.25 0 1 0 0 0 0 0 1 0 5 2 108 0 97 3 0 0 2 0 8-8.25 0 1 1 0 0 0 0 1 0 9 9 62 0 54 3 0 0 9 0 9-9.25 0 0 0 3 0 6 0 1 4 2 0 93 4 62 0 0 0 7 3 10-10.25 0 0 0 2 0 0 0 1 5 0 3 93 2 86 0 0 0 9 8 12-12.25 0 0 0 0 0 0 0 0 4 4 4 88 0 102 0 0 0 6 12 14-14.25 0 0 0 0 0 0 0 0 0 6 0 74 0 94 0 0 0 8 28 16-16.5 0 0 0 0 0 0 0 0 0 0 0 140 0 86 0 0 0 0 4 18-18.5 0 0 0 0 0 4 0 0 0 6 0 142 0 76 0 0 0 0 6 20-20.5 0 0 0 0 0 0 0 0 0 6 0 143 0 81 0 0 0 0 8 24-24.5 0 0 0 0 0 0 0 0 4 8 0 140 0 94 0 0 0 4 8

172

B.6: Lake INV08-6a – Raw Diatom Counts (cont’d)

sp1 sp1 Interval (cm) Navicula cryptocephala Navicula difficillima Navicula disjuncta Navicula pseudoscutiformis Navicula pupula Navicula radiosa Navicula seminulum Navicula utermoehlii Navicula vitiosa Neidium Nitzschia acicularis Nitzschia palea Nitzschia perminuta Nitzschia borealis Pinnularia major Pinnularia microstaunton Pinnularia nodosa Pinnularia anceps Stauroneis 0-0.25 11 8 28 0 11 5 11 5 15 0 1 6 1 0 0 0 0 0 7 0.5-0.75 4 6 35 3 8 4 7 1 11 0 1 4 4 0 0 0 0 0 7 1-1.25 8 9 40 1 14 1 7 0 11 0 2 5 0 1 0 1 0 1 6 1.5-1.75 11 1 47 0 11 3 7 3 21 0 0 5 4 0 0 0 0 0 1 2-2.25 9 0 38 2 12 3 5 1 12 0 1 5 8 0 0 0 1 1 3 3-3.25 3 0 32 2 9 1 10 0 9 0 0 6 2 0 0 0 3 0 1 4-4.25 4 1 13 0 8 0 5 0 1 0 0 2 6 0 0 0 0 0 4 5-5.25 10 0 21 1 5 4 2 1 6 0 0 0 2 0 0 0 0 0 4 6-6.25 2 0 16 3 7 0 7 2 5 0 0 2 2 0 0 0 0 0 1 7-7.25 9 0 5 4 9 2 7 2 10 0 0 0 5 0 0 1 0 0 3 8-8.25 12 0 1 0 3 0 4 4 5 1 0 3 11 0 0 0 0 0 3 9-9.25 6 0 19 1 6 1 6 3 8 0 0 1 5 0 0 2 0 0 0 10-10.25 3 0 6 4 12 0 4 2 7 0 0 0 6 0 2 0 0 0 4 12-12.25 8 0 16 0 10 0 4 4 8 0 0 0 0 0 0 0 0 0 4 14-14.25 6 0 8 0 8 0 4 2 6 0 0 0 0 0 0 0 0 0 6 16-16.5 0 0 10 0 8 0 0 0 10 0 0 4 0 0 0 0 4 0 0 18-18.5 0 0 14 2 6 0 0 0 0 0 0 8 6 0 0 0 0 0 2 20-20.5 0 0 8 0 2 0 0 0 8 0 0 0 0 0 0 0 0 0 0 24-24.5 6 0 8 0 6 0 0 0 4 0 0 0 8 0 0 0 0 0 2

173

B.6: Lake INV08-6a – Raw Diatom Counts (cont’d)

strain IV

tiny Tabellaria quadriseptata Tabellaria quadriseptata Total Diatom valves Chrysophyte Scales Cysts Chrysophyte Plates Protozoan Interval (cm) Stauroneis smithii Surirella Tabellaria floculosa 0-0.25 1 0 4 0 357 8 45 7 0.5-0.75 0 1 2 0 323 6 37 0 1-1.25 3 0 1 1 361 6 58 0 1.5-1.75 0 0 1 0 340 2 34 0 2-2.25 0 0 0 0 313 0 30 0 3-3.25 0 0 2 0 326 1 31 1 4-4.25 1 0 0 0 319 0 23 1 5-5.25 0 0 0 0 336 0 19 0 6-6.25 1 0 2 0 327 0 16 1 7-7.25 0 0 1 0 352 0 6 0 8-8.25 0 0 0 0 260 0 15 0 9-9.25 2 0 3 0 307 0 31 0 10-10.25 0 0 2 0 307 0 13 0 12-12.25 0 0 2 0 318 0 24 0 14-14.25 0 0 2 0 322 0 15 0 16-16.5 0 0 4 0 302 0 10 0 18-18.5 0 0 0 0 308 0 22 0 20-20.5 0 0 5 0 285 0 15 0 24-24.5 2 0 0 0 327 0 30 0

174

B.7: Lake INV08-6b – Raw Diatom Counts

. euglypta . var Interval (cm) acares Achnanthes curtissima Achnanthes gracillima Achnanthes impexiformis Achnanthes lanceolota Achnanthes levanderi Achnanthes minutissima Achnanthes pusilla Achnanthes subatomoides Achnanthes inariensis Amphora libyca Amphora pediculus Amphora Caloneis bacillum Cocconeis placentula Cymbella naviculiformis Cymbopleura amphicephala Diatoma tenuis Diploneis oculata Diploneis parma 0-0.25 20 14 0 0 86 12 20 7 0 14 0 2 2 13 0 0 0 0 0 0.5-0.75 14 8 0 0 111 12 16 6 0 32 0 4 0 28 0 2 0 0 0 1-1.25 6 5 0 0 113 3 28 6 0 20 0 0 0 30 0 1 0 0 0 1.5-1.75 16 0 0 0 126 0 27 2 0 19 0 0 0 30 1 0 0 0 0 2-2.25 8 0 0 2 81 0 2 2 0 28 2 0 0 23 0 0 0 0 0 3-3.25 1 0 0 3 65 0 18 1 0 23 0 0 5 24 0 0 0 0 0 4-4.25 0 1 0 1 35 0 14 0 2 12 2 0 0 6 3 1 1 2 0 5-5.25 0 0 0 0 26 0 5 1 0 16 3 0 0 20 1 0 0 3 0 6-6.25 1 0 0 0 15 0 10 1 2 11 0 0 2 17 0 4 0 1 0 7-7.25 0 0 0 0 0 0 18 2 0 6 5 0 0 15 0 0 2 4 0 8-8.25 8 0 0 0 16 0 10 0 5 4 0 0 5 17 1 0 0 3 0 9-9.25 3 0 0 0 16 0 10 0 0 0 0 0 6 13 0 2 0 0 0 10-10.25 0 0 0 0 8 0 7 2 0 0 2 0 2 11 5 0 0 2 0 14-14.25 1 2 0 2 16 0 7 2 0 0 0 0 2 16 0 2 0 0 1 16-16.5 3 0 0 0 9 0 8 0 0 2 2 0 3 15 2 1 0 2 0 18-18.5 0 0 0 0 4 0 0 0 0 0 2 0 0 10 0 0 0 0 0 19.5-20.0 0 0 2 0 6 0 0 0 0 2 0 0 0 25 0 1 0 0 0

175

B.7: Lake INV08-6b – Raw Diatom Counts (cont’d)

venter exigua v.

sp1 Fragilaria capucina capucina Fragilaria conspicua Fragilaria brevistriata Fragilaria construens Fragilaria v. construens Fragilaria neoproducta Fragilaria pinnata Fragilaria tenera Fragilaria Fragilaria virescens Frustulia rhomboides Gomphonema acuminatum Gomphonema angustatum Gomphonema parvulum Interval (cm) herbridicum Encyonema minutum Encyonema Epithemia turgida faba Eunotia Eunotia incisa Eunotia 0-0.25 0 0 0 0 0 0 0 0 0 0 2 0 72 0 3 0 0 0 5 0.5-0.75 2 0 0 0 0 0 0 0 0 0 0 0 68 0 0 0 0 6 0 1-1.25 1 0 1 0 0 0 0 0 0 0 0 0 51 0 0 0 1 1 0 1.5-1.75 0 0 0 0 0 0 1 0 0 0 0 0 33 0 2 1 1 3 0 2-2.25 1 0 0 0 0 0 3 0 0 1 0 0 57 2 2 0 1 1 6 3-3.25 0 0 2 2 0 0 4 0 0 0 2 0 78 0 0 0 3 0 2 4-4.25 0 0 6 3 2 0 0 0 10 0 2 0 72 4 0 0 1 0 19 5-5.25 0 0 2 0 0 0 0 0 3 4 2 0 61 0 0 0 1 0 20 6-6.25 0 0 1 0 0 0 0 2 1 6 0 0 81 2 0 0 0 2 6 7-7.25 3 0 0 0 0 0 0 0 2 7 0 0 97 3 0 0 0 0 10 8-8.25 0 0 0 0 0 0 0 0 6 6 0 0 89 0 0 0 0 0 8 9-9.25 0 0 0 0 0 0 2 0 4 9 0 1 91 0 0 0 0 0 4 10-10.25 0 2 5 0 0 0 4 0 5 9 0 0 100 0 0 0 0 0 5 14-14.25 0 0 5 2 0 0 2 16 6 8 0 0 88 0 0 0 1 0 3 16-16.5 0 0 8 0 0 3 0 4 13 8 0 0 105 2 0 0 0 0 6 18-18.5 0 0 10 0 0 0 0 5 26 4 0 0 149 3 0 0 0 0 1 19.5-20.0 0 0 7 0 0 0 0 1 32 0 1 0 148 0 0 0 0 0 11

176

B.7: Lake INV08-6b – Raw Diatom Counts (cont’d)

sp1 Interval (cm) Gyrosigma acuminatum Navicula cocconeiformis Navicula cryptocephala Navicula difficillima Navicula disjuncta Navicula halophila Navicula laevissima Navicula menisculus Navicula pseudoscutiformis Navicula pupula Navicula radiosa Navicula seminulum Navicula submuralis Navicula utermoehlii Navicula vitiosa Neidium Nitzschia acicularis Nitzschia gracilis Nitzschia palea 0-0.25 5 0 10 0 0 2 0 0 0 1 4 12 0 0 9 0 0 0 5 0.5-0.75 4 0 16 0 0 0 6 0 0 0 10 10 0 0 0 0 0 0 10 1-1.25 4 0 20 0 0 3 0 0 0 2 0 7 0 0 6 0 0 0 15 1.5-1.75 3 0 16 0 0 0 0 0 0 0 0 5 0 0 5 0 0 0 6 2-2.25 7 0 26 3 1 0 0 0 0 0 0 14 0 0 8 0 1 0 7 3-3.25 7 0 46 0 4 6 2 0 0 3 1 2 9 0 10 0 0 0 18 4-4.25 23 2 47 0 4 10 0 6 0 9 0 10 0 0 8 0 0 4 6 5-5.25 21 2 31 0 3 8 0 1 0 6 3 8 0 0 10 0 0 0 10 6-6.25 19 2 36 0 9 13 0 4 0 5 4 12 0 0 3 0 0 1 18 7-7.25 21 0 34 0 7 0 0 1 0 6 2 1 0 4 4 0 0 0 22 8-8.25 16 0 43 0 1 7 0 0 0 5 4 0 0 6 2 0 2 8 27 9-9.25 17 7 52 0 4 6 0 0 1 4 2 2 0 0 3 0 2 2 34 10-10.25 18 0 46 0 7 0 0 0 0 11 0 0 0 2 0 0 2 0 17 14-14.25 15 7 25 0 7 3 0 2 0 12 0 0 0 0 6 1 0 0 23 16-16.5 18 2 34 0 12 0 0 0 0 11 2 2 0 0 1 0 0 0 21 18-18.5 21 0 21 0 17 0 0 4 0 8 0 2 0 0 4 0 0 0 10 19.5-20.0 15 0 27 0 2 0 0 0 0 0 3 2 0 0 6 0 0 0 6

177

B.7: Lake INV08-6b – Raw Diatom Counts (cont’d)

strain III strain IV Total diatom valves diatom Total Chrysophyte Scales Cysts Chrysophyte Phytoliths Interval (cm) Nitzschia perminuta borealis Pinnularia brauniana Pinnularia major Pinnularia microstaunton Pinnularia nodosa Pinnularia gibba Rhopalodia anceps Stauroneis phoenicenteron Stauroneis Stauroneis smithii Tabellaria flocculosa Tabellaria floculosa 0-0.25 8 0 0 0 0 0 0 0 1 0 0 0 329 0 6 0 0.5-0.75 8 0 0 0 0 0 0 0 0 0 0 0 373 0 4 0 1-1.25 20 0 0 0 0 0 0 0 0 0 0 0 344 0 4 0 1.5-1.75 13 0 0 0 0 0 0 0 0 0 0 0 310 0 8 0 2-2.25 22 2 0 0 0 0 0 0 1 0 0 0 314 0 8 0 3-3.25 18 3 0 0 0 0 0 1 0 0 0 1 364 1 8 0 4-4.25 12 0 0 0 0 0 0 3 0 0 0 0 343 0 11 1 5-5.25 16 2 6 0 0 0 0 2 0 0 0 0 297 0 11 0 6-6.25 13 1 0 0 0 0 3 7 0 0 0 0 315 0 20 0 7-7.25 11 5 0 0 0 0 0 8 0 0 0 0 300 0 13 0 8-8.25 28 2 0 0 2 0 1 6 0 0 0 0 338 0 13 0 9-9.25 26 0 0 1 0 0 1 1 0 0 0 0 326 0 13 1 10-10.25 14 4 0 0 0 0 1 4 0 0 1 0 296 0 21 0 14-14.25 19 8 0 0 0 2 0 6 0 1 0 0 319 0 28 0 16-16.5 17 8 0 0 1 0 1 5 0 0 0 0 331 0 27 0 18-18.5 2 0 0 0 3 0 0 0 0 1 1 0 308 0 18 0 19.5-20.0 2 0 0 0 0 0 0 0 0 0 0 0 299 0 25 0

178

B.8: Lake INV08-7a – Raw Diatom Counts

euglypta nivalis var. v. Interval (cm) acares Achnanthes carissima Achnanthes curtissima Achnanthes impexiformis Achnanthes lacus-vulcani Achnanthes levanderi Achnanthes marginulata Achnanthes minutissima Achnanthes pseudoarvensis Achnanthes pusilla Achnanthes subatomoides Achnanthes ventralis Achnanthes libyca Amphora Asterionella formosa ambigua Aulacoseira distans Aulacoseira Brachysira neoexilis Caloneis bacillum Cocconeis placentula 0-0.25 0 4 4 0 0 0 0 4 0 0 29 0 0 35 0 0 2 1 0 0.5-0.75 4 1 5 1 0 0 0 6 1 6 20 0 0 28 0 0 5 1 1 1-1.25 2 0 0 0 0 0 0 4 0 5 5 0 0 15 2 0 1 2 0 1.5-1.75 2 0 0 0 0 0 0 2 0 0 14 0 1 12 5 0 1 2 0 2-2.25 2 0 0 2 0 0 0 4 0 2 18 0 0 18 2 0 0 0 0 3-3.25 0 0 2 1 0 9 0 1 0 7 9 0 0 3 3 0 0 5 1 4-4.25 2 0 1 0 0 0 3 3 0 2 11 0 0 7 3 0 0 2 0 5-5.25 0 0 7 0 0 1 7 2 0 3 20 0 1 1 1 0 0 2 0 6-6.25 0 0 5 0 0 4 4 4 0 0 13 4 0 6 0 0 0 0 1 7-7.25 0 0 7 1 0 0 5 0 0 3 9 0 2 10 0 1 0 0 0 8-8.25 3 0 2 0 5 0 9 5 0 1 13 0 1 9 0 6 0 0 0 9-9.25 1 0 0 0 3 1 10 3 0 1 5 3 2 0 0 3 0 2 0 10-10.25 0 0 0 0 6 0 0 3 0 13 4 2 1 4 0 3 0 0 0 12-12.25 2 0 0 0 5 0 0 0 0 4 4 0 1 4 0 3 7 0 1 14-14.25 2 1 0 1 2 0 0 0 0 10 13 0 1 6 0 0 0 0 0 16-16.5 3 0 0 0 0 0 0 0 0 8 3 0 0 8 0 2 0 0 0 18-18.5 0 0 0 0 2 0 0 4 0 7 5 1 0 4 2 0 0 0 0

179

B.8: Lake INV08-7a – Raw Diatom Counts (cont’d)

venter . trigona trigona . v

sp1 Fragilaria capucina capucina Fragilaria conspicua Fragilaria brevistriata Fragilaria construens Fragilaria v. construens Fragilaria var. "triangle" construens Fragilaria neoproducta Fragilaria pinnata Fragilaria pinnata Fragilaria tenera Fragilaria Interval (cm) Cymbella naviculiformis Cymbopleura amphicephala Diploneis oculata herbridicum Encyonema lunatum Encyonema faba Eunotia Eunotia incisa Eunotia serra Eunotia 0-0.25 0 1 0 0 2 0 3 0 1 6 4 12 0 214 4 0 28 0 2 0.5-0.75 0 1 0 0 0 4 1 0 0 5 0 0 0 261 14 0 25 0 0 1-1.25 2 0 0 0 0 0 0 0 1 0 0 74 0 92 7 0 31 0 3 1.5-1.75 0 0 0 0 1 1 1 1 0 11 0 31 0 206 4 0 54 6 4 2-2.25 0 0 1 0 0 0 1 0 0 7 0 13 4 184 11 0 34 0 0 3-3.25 0 0 2 1 0 0 5 0 0 0 0 14 0 180 0 0 27 4 0 4-4.25 0 0 0 0 3 0 5 0 0 5 0 0 0 176 0 0 18 7 0 5-5.25 0 0 0 1 0 6 0 0 0 3 0 8 0 171 0 0 0 5 0 6-6.25 2 0 0 0 0 0 2 0 0 9 0 0 8 195 0 0 14 4 0 7-7.25 4 0 0 0 0 7 0 0 0 5 0 22 0 188 0 0 16 11 0 8-8.25 2 0 0 1 2 2 2 0 0 1 0 17 0 149 0 0 2 4 2 9-9.25 0 0 0 3 1 10 0 0 0 0 0 8 0 171 0 0 15 4 0 10-10.25 1 0 0 1 2 4 0 0 0 1 0 7 0 190 0 0 10 1 0 12-12.25 0 0 0 6 0 0 7 0 0 0 0 0 0 251 0 0 22 3 0 14-14.25 0 0 0 3 4 4 7 0 2 0 0 9 0 186 2 5 14 0 0 16-16.5 0 0 0 1 0 2 4 0 0 0 1 18 0 217 1 4 20 0 3 18-18.5 0 1 0 2 2 2 0 0 0 0 0 0 0 204 0 0 30 0 0

180

B.8: Lake INV08-7a – Raw Diatom Counts (cont’d)

exigua v.

sp1 Interval (cm) Fragilaria virescens Frustulia rhomboides Gomphonema acuminatum Gomphonema angustatum Gomphonema parvulum Gyrosigma acuminatum Navicula cocconeiformis Navicula cryptocephala Navicula difficillima Navicula disjuncta Navicula laevissima Navicula pseudoscutiformis Navicula pseudoventralis Navicula pupula Navicula radiosa Navicula seminulum Navicula utermoehlii Navicula vitiosa Neidium 0-0.25 46 0 0 0 0 0 0 3 6 4 0 0 0 5 0 12 0 8 2 0.5-0.75 85 0 0 0 1 0 0 1 3 7 1 4 0 3 0 12 0 4 0 1-1.25 23 0 0 0 0 0 0 0 4 0 0 4 2 2 1 18 4 2 0 1.5-1.75 35 0 0 0 0 0 0 0 4 0 0 9 0 1 0 8 0 5 0 2-2.25 40 2 1 0 2 0 0 2 3 4 0 3 1 7 0 21 0 0 0 3-3.25 35 0 0 0 0 0 0 0 0 4 0 5 0 0 0 11 0 0 0 4-4.25 56 2 0 0 2 0 1 3 0 5 0 6 0 4 0 11 0 3 0 5-5.25 30 0 2 0 1 0 1 2 0 0 1 7 0 1 0 7 0 6 0 6-6.25 54 0 0 0 4 0 1 2 0 4 0 11 0 7 0 12 1 7 0 7-7.25 40 0 0 0 6 0 4 4 2 5 0 7 0 3 0 4 0 9 0 8-8.25 40 0 0 0 4 0 1 1 0 5 0 0 0 1 0 11 0 6 0 9-9.25 50 0 0 0 2 0 2 2 0 8 0 6 0 2 0 13 0 5 0 10-10.25 56 1 0 0 3 0 0 3 0 8 0 2 0 5 0 20 3 6 0 12-12.25 69 0 0 0 3 0 3 0 0 11 0 2 0 2 0 4 0 3 0 14-14.25 51 0 0 1 0 0 1 0 0 12 0 1 0 6 0 6 0 10 0 16-16.5 42 0 0 0 2 0 2 0 5 0 1 0 4 0 6 0 6 0 18-18.5 51 0 0 3 3 2 2 0 0 2 0 1 0 5 0 3 0 5 0

181

B.8: Lake INV08-7a – Raw Diatom Counts (cont’d)

strain III strain IV Tabellaria quadriseptata Tabellaria quadriseptata sp2 unknown sp1 unknown valves diatom Total Chrysophyte Scales Cysts Chrrysophyte Interval (cm) Nitzschia acicularis Nitzschia gracilis Nitzschia palea Nitzschia perminuta brauniana Pinnularia microstaunton Pinnularia nodosa Pinnularia anceps Stauroneis phoenicenteron Stauroneis Stauroneis smithii Tabellaria fenestrata Tabellaria flocculosa Tabellaria floculosa 0-0.25 1 0 10 0 0 1 0 0 0 0 0 0 9 3 0 0 466 3 61 0.5-0.75 3 0 6 2 0 1 2 6 0 2 0 0 8 1 0 0 542 4 53 1-1.25 0 0 0 1 0 0 1 0 0 0 0 0 7 0 0 0 315 0 28 1.5-1.75 0 0 10 0 0 0 2 0 0 0 0 0 5 0 0 0 438 3 34 2-2.25 0 0 0 2 0 1 3 1 0 0 0 0 10 2 1 4 413 2 42 3-3.25 0 0 1 5 0 0 1 2 0 0 0 2 8 0 0 0 348 0 23 4-4.25 0 0 0 2 0 0 2 1 0 0 0 2 9 0 0 0 357 1 32 5-5.25 0 0 5 7 0 0 0 2 0 1 0 2 10 0 0 0 324 0 29 6-6.25 0 0 3 4 0 0 1 2 0 0 0 0 5 0 0 0 393 0 29 7-7.25 0 2 0 6 0 8 0 3 3 0 1 0 9 0 0 0 407 0 37 8-8.25 0 0 0 2 3 1 0 0 1 0 3 0 6 0 0 0 323 0 32 9-9.25 0 0 2 6 0 0 0 4 0 0 0 0 13 0 0 0 361 0 30 10-10.25 0 0 0 1 1 1 0 3 1 0 2 0 1 0 0 0 370 1 50 12-12.25 0 0 1 4 2 0 0 1 0 0 1 0 5 0 0 0 431 0 58 14-14.25 0 0 1 5 0 2 0 10 3 0 0 0 10 0 0 0 391 0 64 16-16.5 0 0 4 5 0 0 0 11 1 0 2 0 8 0 0 0 394 0 66 18-18.5 0 0 0 2 0 3 0 3 1 0 0 0 3 0 0 0 355 0 57

182

B.9: Lake INV07-7b – Raw Diatom Counts

euglypta nivalis var. var.

sp1 Interval (cm) acares Achnanthes curtissima Achnanthes didyma Achnanthes exigua Achnanthes gracillima Achnanthes impexiformis Achnanthes lanceolota Acnanthes levanderi Achnanthes minutissima Acnanthes Acnanthes pusilla subatomoides Achnanthes ventralis Achnanthes Achnanthes inariensis Amphora libyca Amphora Asterionella formosa distans Aulacoseira Caloneis bacillum Caloneis bacillum Cocconeis placentula 0.0-0.2 0 1 5 12 3 4 3 7 4 6 0 0 4 11 13 20 0 0 1 0.4-0.6 0 4 0 9 2 5 5 0 1 1 2 0 9 26 13 19 0 0 1 0.8-1.0 0 0 0 8 2 6 11 1 2 1 0 0 15 14 10 3 0 3 1 1.8-2.0 0 0 0 12 5 4 9 0 0 0 1 0 18 11 9 2 0 2 0 2.4-2.6 2 0 0 10 9 3 13 0 0 4 0 1 20 20 13 1 0 2 0 3.6-3.8 0 0 0 4 3 1 13 0 2 1 0 0 47 17 28 0 0 0 1 4.8-5.0 0 0 0 4 0 0 9 0 1 1 0 0 26 6 16 0 0 0 1 6.0-6.2 0 0 0 1 2 0 2 0 0 0 0 0 24 3 17 2 0 7 0 6.6-6.8 0 0 0 8 0 0 9 0 0 0 0 0 17 13 22 2 0 0 0 7.8-8.0 0 0 0 0 0 0 6 0 0 0 0 0 9 5 28 0 0 0 0 8.4-8.6 0 0 0 0 0 0 7 0 2 2 0 0 4 4 6 4 2 0 0 9.6-9.8 0 0 0 0 0 2 7 0 2 0 0 0 5 4 8 3 0 0 0 11.4-11.6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7 0 0 0 2 14.0-14.2 0 0 0 2 0 0 2 0 0 0 0 0 2 2 6 2 0 0 1 16.4-16.8 0 0 0 0 0 0 4 0 0 0 0 0 0 0 14 0 0 0 2 19.2-19.6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 22.0-22.4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 0 0 0 0

183

B.9: Lake INV07-7b – Raw Diatom Counts (cont’d)

. binodis . . pumilla . venter

sp1 sp1 Interval (cm) tholiformis Cyclostephanos Cyclotella pseudostelligera Cymbella minuta Cymbella Cymbopleura amphicephala Diatoma tenuis elongatum Diploneis elliptica Diploneis oblongella Diploneis oculata Diploneis parma Diploneis Eunotia incisa praerupta Eunotia brevistriata Fragilaria capucina Fragilaria construens Fragilaria var construens Fragilaria var construens Fragilaria var construens Fragilaria 0.0-0.2 10 125 0 1 7 2 15 1 28 8 0 1 0 25 14 0 1 0 4 0.4-0.6 2 82 0 1 2 0 21 1 25 14 0 3 0 29 6 0 0 0 8 0.8-1.0 2 33 0 0 11 0 11 0 14 13 2 0 2 18 5 4 0 0 9 1.8-2.0 2 9 0 0 7 0 15 0 15 27 2 0 0 71 0 0 0 0 3 2.4-2.6 1 1 2 0 4 1 18 0 13 29 1 2 0 61 0 0 0 0 5 3.6-3.8 1 2 0 0 9 0 10 0 23 10 0 0 0 91 0 0 0 0 4 4.8-5.0 0 0 1 0 4 0 20 0 10 16 0 0 0 83 0 1 0 0 7 6.0-6.2 1 2 1 0 4 0 11 0 6 11 2 0 0 92 0 0 0 2 12 6.6-6.8 1 3 0 0 1 0 11 0 7 16 0 0 0 93 3 0 1 2 7 7.8-8.0 0 4 0 0 2 0 12 0 5 11 0 0 0 131 2 0 0 5 8 8.4-8.6 0 3 0 0 0 0 4 0 4 4 0 1 0 82 0 0 0 0 3 9.6-9.8 0 3 1 0 0 0 1 0 1 10 2 2 0 96 3 0 0 0 11 11.4-11.6 0 0 0 0 0 0 0 0 1 2 2 1 0 66 0 0 0 0 5 14.0-14.2 0 1 0 0 1 0 0 0 0 0 0 0 0 51 2 0 4 0 8 16.4-16.8 0 2 0 0 0 0 0 0 0 2 0 0 0 74 0 0 0 0 12 19.2-19.6 0 0 0 0 0 0 0 0 0 0 0 0 0 60 0 0 0 0 18 22.0-22.4 0 0 0 0 0 0 0 0 0 0 0 0 1 25 0 1 0 0 8

184

B.9: Lake INV07-7b – Raw Diatom Counts (cont’d)

. menisculus . var . subcapita var . Interval (cm) neoproducta Fragilaria parasitica Fragilaria pinnata Fragilaria Gomphonema parvulum Gyrosigma acuminatum Navicula cocconeiformis Navicula cryptocephala Navicula difficillima Navicula disjuncta Navicula laevissima Navicula menisculus Navicula pseudoscutiformis Navicula pupula Navicula pupula Navicula radiosa Navicula salinarum Navicula seminulum Navicula submuralis Navicula utermoelhii 0.0-0.2 4 3 29 0 0 2 26 0 2 0 0 0 0 3 5 1 0 0 1 0.4-0.6 10 7 45 0 4 0 11 0 11 1 4 0 3 0 9 0 1 0 0 0.8-1.0 11 2 28 0 3 0 9 2 1 0 2 0 4 0 7 0 2 0 0 1.8-2.0 28 8 32 0 0 3 10 0 6 1 0 0 2 0 7 0 2 0 2 2.4-2.6 27 10 42 0 3 0 4 6 5 0 0 0 0 0 2 0 0 0 0 3.6-3.8 4 4 26 0 10 0 1 1 0 1 0 2 4 0 4 0 0 1 0 4.8-5.0 7 2 52 0 10 2 0 0 0 0 2 1 1 0 2 0 0 0 1 6.0-6.2 14 0 50 4 13 1 3 0 1 2 0 0 1 0 3 0 0 0 0 6.6-6.8 12 1 46 3 20 0 5 0 0 0 1 0 0 0 0 0 0 0 0 7.8-8.0 9 1 116 1 22 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8.4-8.6 21 2 132 4 18 0 0 0 1 0 0 0 0 0 0 0 0 0 0 9.6-9.8 11 1 120 2 16 0 2 0 5 0 0 0 0 0 0 0 0 0 0 11.4-11.6 4 0 87 0 18 0 1 0 0 1 0 0 0 0 1 0 0 0 0 14.0-14.2 8 2 170 2 19 0 3 0 0 0 0 0 0 0 1 0 0 0 1 16.4-16.8 12 0 144 0 32 0 0 0 0 0 0 0 0 0 0 0 0 0 0 19.2-19.6 6 0 148 0 14 0 0 0 0 0 0 0 0 0 4 0 0 0 0 22.0-22.4 9 0 102 1 22 0 0 0 0 0 0 0 0 0 0 0 0 0 0

185

B.9: Lake INV07-7b – Raw Diatom Counts (cont’d)

. linearis var strain IV

sp1

huge sp1 Interval (cm) Navicula vitiosa Nitzschia acicularis Nitzschia bacillum Nitzschia palea Nitzschia perminuta Nitzschia recta Nitzschia Nitzschia brauniana Pinnularia subgibba Pinnularia anceps Stauroneis phoenicenteron Stauroneis Stauroneis smithii wislouchii Stauroneis Stephanodiscus Surirella amphioxys Surirella amphioxys Surirella linearis Tabellaria flocculosa Tabellaria flocculosa 0.0-0.2 9 4 5 39 12 7 14 2 1 0 0 0 0 0 0 0 5 1 0 0.4-0.6 10 3 0 22 22 0 17 0 1 0 0 0 1 0 2 1 0 0 1 0.8-1.0 6 0 4 17 22 0 9 0 0 0 0 0 0 0 0 0 3 0 0 1.8-2.0 3 2 6 19 14 0 5 0 0 0 0 0 0 2 1 1 1 0 0 2.4-2.6 8 0 2 8 9 0 11 0 0 0 0 1 0 0 0 3 1 1 0 3.6-3.8 8 0 1 12 8 0 2 0 0 0 0 0 0 0 0 2 0 0 0 4.8-5.0 5 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 1 0 0 6.0-6.2 2 0 4 4 2 0 0 0 0 0 1 1 0 0 0 0 0 0 0 6.6-6.8 0 0 0 5 7 0 0 0 0 0 0 1 0 1 0 4 1 2 0 7.8-8.0 2 0 0 4 3 0 0 0 0 0 1 5 0 0 0 2 1 0 0 8.4-8.6 0 0 0 6 0 0 0 0 0 0 0 0 0 0 0 1 1 0 2 9.6-9.8 1 2 0 3 3 0 0 0 0 0 0 0 0 0 0 2 3 0 2 11.4-11.6 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 14.0-14.2 0 2 0 3 0 0 0 0 0 0 0 1 0 0 0 2 1 0 0 16.4-16.8 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 2 19.2-19.6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 4 0 0 22.0-22.4 0 0 0 4 0 0 0 0 0 0 0 1 0 0 0 2 1 0 1

186

B.9: Lake INV07-7b – Raw Diatom Counts (cont’d)

Interval (cm) Unknown sp1 valves diatom Total Chrysophyte scales Cysts Chrysophyte Phytoliths Plates Protozoan Sponge Spicules 0.0-0.2 42 553 3 108 0 1 0 0.4-0.6 46 523 1 95 0 0 0 0.8-1.0 35 368 1 61 0 0 0 1.8-2.0 24 403 0 46 0 0 0 2.4-2.6 22 401 0 40 0 1 0 3.6-3.8 18 376 0 52 0 0 0 4.8-5.0 6 300 0 29 0 0 0 6.0-6.2 6 314 0 48 0 0 0 6.6-6.8 4 329 0 55 0 0 0 7.8-8.0 3 398 0 55 1 1 0 8.4-8.6 0 320 0 45 0 0 0 9.6-9.8 4 338 0 80 0 0 1 11.4-11.6 0 201 0 80 0 0 0 14.0-14.2 2 301 0 72 0 0 0 16.4-16.8 0 302 0 60 0 0 0 19.2-19.6 0 256 0 80 0 0 0 22.0-22.4 0 183 0 31 2 0 1

187

B.10: Lake INV08-9a – Raw Diatom Counts

sp1 unknown sp1 unknown unknown sp2 unknown Interval (cm) acares Achnanthes carissima Achnanthes curtissima Achnanthes impexiformis Achnanthes lacus-vulcani Achnanthes levanderi Achnanthes minutissima Achnanthes peterseneii Achnanthes pusilla Achnanthes subatomoides Achnanthes Achnanthes Achnanthes Achnanthes Amphora inariensis inariensis Amphora libyca Amphora pediculus Amphora Asterionella formosa ambigua Aulacoseira Aulacoseira invisitatus Cyclostephanos 0-0.25 6 3 0 3 12 0 4 0 3 16 22 4 0 1 5 3 0 23 0 0.5-0.75 8 2 6 5 15 0 2 0 5 16 6 3 0 1 0 0 0 10 0 1-1.25 15 1 8 5 2 2 12 0 3 15 3 2 1 0 0 3 0 14 0 1.5-1.75 27 0 0 5 1 3 6 0 4 16 0 1 0 3 0 0 0 8 0 2-2.25 27 0 0 1 0 2 5 0 3 15 0 2 0 0 0 3 0 19 0 3-3.25 20 0 0 0 3 0 0 0 13 8 0 1 0 0 0 3 0 16 0 4-4.25 14 0 0 2 0 1 4 0 4 10 0 1 0 0 0 0 1 8 1 5-5.25 0 1 0 4 0 4 2 0 0 6 0 2 0 1 0 0 0 7 1 6-6.25 8 0 7 1 2 0 4 0 3 9 0 0 0 0 0 2 0 4 0 7-7.25 10 9 4 4 0 0 0 0 8 8 0 2 1 2 0 3 0 12 0 8-8.25 6 0 2 3 0 0 6 0 4 9 0 0 0 1 0 3 0 13 0 9-9.25 7 0 2 0 0 0 0 0 4 8 0 0 0 0 0 0 0 5 0 10-10.25 0 0 4 0 0 0 0 4 0 0 0 0 0 0 0 0 0 10 0 12-12.25 8 0 0 0 0 0 0 0 4 8 0 0 0 0 0 0 0 4 0 14-14.25 0 0 0 0 0 0 2 0 4 4 0 0 0 4 0 0 0 6 0 15.5-16.0 0 0 0 0 0 0 6 0 0 12 0 0 0 0 0 0 0 0 0

leptostauron leptostauron venter v. v. exigua v. v.

sp2 sp1 Fragilaria capucina capucina Fragilaria binodis Fragilaria brevistriata Fragilaria v. construens Fragilaria var. "triangle" construens Fragilaria leptostauron Fragilaria pinnata Fragilaria tenera Fragilaria Fragilaria virescens Eunotia Eunotia Interval (cm) Diploneis elliptica Diploneis oblongella herbridicum Encyonema lunatum Encyonema minutum Encyonema faba Eunotia Eunotia incisa Eunotia serra Eunotia 0-0.25 1 0 0 0 0 5 6 0 0 0 0 1 13 81 6 0 35 0 7 0.5-0.75 0 1 0 1 0 6 3 0 0 0 1 0 10 93 2 0 49 0 13 1-1.25 0 0 1 0 0 7 0 1 0 0 0 0 11 109 5 2 54 1 19 1.5-1.75 0 0 0 3 0 8 2 0 0 0 0 0 6 123 2 0 36 0 10 2-2.25 0 0 0 0 0 7 0 0 0 0 0 0 1 92 5 0 35 0 13 3-3.25 0 0 0 0 0 6 0 0 0 0 1 0 5 106 1 0 44 0 20 4-4.25 0 0 0 0 1 4 2 0 0 0 0 0 15 135 8 0 42 0 21 5-5.25 0 0 0 0 0 1 0 0 0 2 5 0 2 98 2 0 25 0 23 6-6.25 0 2 0 0 0 4 0 0 0 0 0 0 25 128 3 0 31 0 25 7-7.25 0 0 0 1 0 7 0 0 0 0 2 3 12 102 2 0 44 0 17 8-8.25 0 0 0 1 0 2 0 0 1 0 2 0 9 133 0 0 35 0 11 9-9.25 0 0 0 2 0 4 0 0 0 0 0 0 13 140 0 0 54 0 10 10-10.25 0 0 0 0 0 0 0 0 0 0 0 4 12 150 0 0 46 0 6 12-12.25 0 0 0 0 0 4 0 0 0 0 2 0 6 152 0 0 60 0 12 14-14.25 0 0 0 0 0 0 0 0 0 0 0 0 12 158 0 0 60 0 8 15.5-16.0 0 0 0 0 0 4 0 0 0 0 0 0 18 156 0 0 72 0 0

188

B.10: Lake INV08-9a – Raw Diatom Counts (cont’d)

sp1 Interval (cm) Frustulia rhomboides Gomphonema angustatum Gomphonema parvulum Gyrosigma acuminatum Navicula cocconeiformis Navicula cryptocephala Navicula difficillima Navicula disjuncta Navicula mediocris Navicula pseudoscutiformis Navicula pseudoventralis Navicula pupula Navicula seminulum Navicula utermoehlii Navicula vitiosa Navicula Nitzschia palea Nitzschia perminuta brauniana Pinnularia 0-0.25 0 0 0 0 0 3 0 3 0 2 0 0 32 0 30 0 0 0 0 0.5-0.75 0 0 0 0 0 0 1 3 0 1 2 2 33 2 35 0 1 0 1 1-1.25 0 0 0 0 0 0 0 1 1 6 0 3 21 1 39 0 0 2 1 1.5-1.75 0 0 0 0 0 1 0 5 0 0 4 1 22 1 39 0 0 2 0 2-2.25 0 0 0 0 0 1 2 1 0 2 0 2 20 1 51 0 0 2 0 3-3.25 0 1 0 0 0 0 2 0 0 0 0 6 34 0 41 0 0 0 0 4-4.25 0 0 0 0 0 1 0 0 0 0 0 0 13 1 20 0 0 0 0 5-5.25 0 0 0 0 0 1 0 2 0 0 0 1 9 0 13 1 0 0 0 6-6.25 0 1 0 4 0 0 0 4 0 0 0 1 13 0 22 0 1 2 0 7-7.25 0 0 2 7 0 0 2 3 0 1 0 5 10 3 17 0 0 0 0 8-8.25 0 0 0 0 0 0 0 2 0 0 0 3 15 0 35 0 0 0 0 9-9.25 0 0 0 14 2 2 0 5 0 2 0 0 10 0 16 0 0 0 0 10-10.25 6 0 0 8 0 0 4 6 0 0 0 0 14 0 16 0 0 0 0 12-12.25 0 0 0 2 0 0 0 4 0 0 0 0 10 0 16 0 0 0 0 14-14.25 0 0 0 0 0 0 0 4 0 0 0 0 12 0 20 0 0 4 0 15.5-16.0 0 0 0 0 0 4 0 0 0 0 0 0 11 0 21 0 0 0 0

strain IV

sp1 sp2 girdle sp2 Interval (cm) gibba Pinnularia microstaunton Pinnularia Pinnularia unknown sp1 sp1 unknown valves diatom Total Chrysophyte Scales Cysts Chrysophyte Plates Protozoan Sponge Spicules Pinnularia Pinnularia Stauroneis anceps anceps Stauroneis phoenicenteron Stauroneis Tabellaria floculosa 0-0.25 0 0 1 3 0 0 0 0 334 10 38 1 0 0.5-0.75 0 0 0 0 0 0 0 0 339 5 23 1 0 1-1.25 1 0 0 0 1 0 2 2 377 4 26 0 0 1.5-1.75 0 1 0 0 2 0 3 1 346 0 30 0 0 2-2.25 0 0 0 0 0 0 3 0 315 2 16 0 0 3-3.25 0 0 0 0 2 0 3 0 336 1 26 0 0 4-4.25 0 0 0 0 2 0 2 0 313 1 40 1 0 5-5.25 0 0 0 0 1 0 0 0 214 2 22 0 0 6-6.25 0 0 0 0 0 2 7 0 315 1 43 1 0 7-7.25 0 0 0 0 2 0 1 2 308 1 27 2 0 8-8.25 2 0 0 0 2 0 0 0 300 0 22 0 1 9-9.25 0 0 0 0 2 0 2 0 304 0 39 0 3 10-10.25 0 8 0 0 0 0 6 0 304 0 24 0 0 12-12.25 0 0 0 0 0 0 6 0 298 2 4 0 0 14-14.25 0 0 0 0 0 0 2 0 300 2 14 0 0 15.5-16.0 0 0 0 0 0 0 9 0 313 0 12 0 0

189

B.11: Lake INV08-9b – Raw Diatom Counts

. euglypta . var unknown sp1 unknown unknown sp2 unknown Interval (cm) acares Achnanthes curtissima Achnanthes exigua Achnanthes lanceolota Achnanthes levanderi Achnanthes marginulata Achnanthes minutissima Achnanthes pusilla Achnanthes subatomoides Achnanthes Achnanthes Achnanthes Achnanthes Amphora inariensis inariensis Amphora libyca Amphora pediculus Amphora Caloneis bacillum Cocconeis placentula Cyclotella pseudostelligera Cyclotella stelligera Cymbopleura amphicephala 0-0.25 0 6 2 0 10 0 25 0 1 4 0 19 2 0 0 0 0 0 0 0.5-0.75 1 4 3 0 8 0 16 0 0 9 2 18 2 7 0 1 0 0 0 1-1.25 0 4 0 2 7 0 12 0 0 1 0 22 0 5 0 3 0 0 0 1.5-1.75 0 0 0 3 11 0 12 0 0 0 0 13 1 0 2 0 0 0 1 2-2.25 0 11 0 0 0 2 6 1 0 0 0 24 0 13 2 0 1 0 0 3-3.25 0 10 2 2 2 0 2 1 0 3 0 22 5 0 1 1 0 0 2 4-4.25 2 8 0 2 0 0 9 0 0 1 0 12 2 0 2 0 0 0 2 5-5.25 4 0 0 2 1 0 5 0 0 4 0 11 0 0 2 0 0 1 0 6-6.25 0 0 0 2 2 0 4 0 0 0 0 16 2 0 0 1 0 0 0 7-7.25 5 0 0 2 2 0 2 0 0 0 0 2 0 5 0 0 0 0 1 8-8.25 2 0 0 0 0 0 0 0 0 0 0 4 0 12 0 0 0 0 0 9-9.25 2 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 10-10.25 0 0 0 0 0 0 4 0 0 0 0 4 0 0 0 2 0 0 0 12-12.25 4 0 0 4 0 0 10 0 0 0 0 0 0 6 0 0 0 0 0 14-14.25 0 0 0 0 0 0 9 0 0 0 0 9 0 0 0 0 0 0 0 16-16.5 0 0 0 0 0 0 0 0 0 0 0 8 0 0 0 0 0 0 0 18-18.5 0 0 0 0 0 0 0 0 0 0 0 3 0 6 0 0 0 0 0

190

B.11: Lake INV08-9b – Raw Diatom Counts (cont’d)

venter exigua v.

sp1 girdle sp1 Fragilaria capucina capucina Fragilaria conspicua Fragilaria brevistriata Fragilaria construens Fragilaria v. construens Fragilaria parasitica Fragilaria pinnata Fragilaria tenera Fragilaria Fragilaria virescens Gomphonema acuminatum Gomphonema acuminatum Gomphonema parvulum Interval (cm) Denticula Diatoma tenuis Diploneis oculata Diploneis parma herbridicum Encyonema minutum Encyonema Epithemia Eunotia 0-0.25 0 0 1 0 1 0 0 0 0 0 26 12 25 0 185 2 2 0 3 0.5-0.75 0 0 2 0 0 0 0 2 0 0 41 14 28 0 239 0 0 0 7 1-1.25 0 0 0 1 0 0 0 0 4 0 26 4 17 2 166 2 0 0 0 1.5-1.75 0 0 0 0 0 0 5 0 4 7 65 17 9 0 231 0 0 0 1 2-2.25 0 0 0 0 0 0 0 0 1 0 64 5 11 3 238 4 0 0 4 3-3.25 2 2 1 0 0 0 0 0 0 2 47 12 6 0 199 0 0 0 0 4-4.25 0 0 0 0 0 0 2 0 0 8 47 13 6 0 187 0 0 2 2 5-5.25 0 0 0 0 0 0 0 0 0 0 61 1 7 0 204 0 0 0 1 6-6.25 0 0 0 0 0 0 3 0 0 0 57 10 5 0 197 0 0 0 0 7-7.25 0 0 0 0 0 1 0 0 0 0 79 9 3 0 222 0 0 0 0 8-8.25 0 0 0 0 0 0 2 0 0 2 70 0 6 0 282 0 0 0 0 9-9.25 0 0 0 2 0 0 0 0 0 2 72 0 8 0 216 0 0 0 0 10-10.25 0 0 0 0 0 0 0 0 0 2 72 0 0 0 284 0 0 0 4 12-12.25 0 0 0 0 0 0 0 0 0 0 60 4 0 0 198 0 0 0 0 14-14.25 0 0 0 0 0 0 0 0 0 0 45 0 9 0 237 0 0 0 0 16-16.5 0 0 0 0 0 0 0 0 0 0 56 0 0 0 228 0 0 0 0 18-18.5 0 0 0 0 0 0 0 0 0 0 61 6 0 0 203 0 0 0 0

191

B.11: Lake INV08-9b – Raw Diatom Counts (cont’d)

sp1 sp1 Interval (cm) Gyrosigma acuminatum Navicula cocconeiformis Navicula cryptocephala Navicula difficillima Navicula disjuncta Navicula halophila Navicula menisculus Navicula pseudoscutiformis Navicula pupula Navicula radiosa Navicula utermoehlii Navicula vitiosa Navicula Nitzschia acicularis Nitzschia gracilis Nitzschia palea Nitzschia perminuta Nitzschia tubicola Nitzschia 0-0.25 10 6 20 0 0 4 0 1 0 0 2 1 2 0 0 6 2 0 4 0.5-0.75 5 2 11 0 0 4 0 0 2 0 0 3 0 1 4 7 5 0 0 1-1.25 2 0 7 0 2 1 0 0 0 0 1 2 0 0 0 9 6 0 1 1.5-1.75 4 0 12 0 2 0 3 0 0 0 1 0 0 2 0 0 1 0 3 2-2.25 4 2 6 0 3 0 6 0 0 2 0 1 0 0 0 2 2 0 2 3-3.25 6 1 1 1 0 0 6 0 0 4 4 0 0 0 0 5 0 3 0 4-4.25 4 1 2 0 2 0 2 0 0 0 2 1 0 0 0 4 5 0 0 5-5.25 4 0 6 0 1 0 2 0 1 0 2 0 0 0 0 0 0 0 0 6-6.25 3 0 2 0 0 0 0 0 0 0 1 0 0 0 0 0 2 0 0 7-7.25 3 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 8-8.25 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 9-9.25 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 0 0 0 10-10.25 2 0 6 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 12-12.25 4 0 4 0 0 0 4 0 0 0 0 0 0 0 0 8 2 0 0 14-14.25 19 0 9 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 16-16.5 0 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 10 0 0 18-18.5 5 0 4 0 0 0 0 0 0 0 0 0 0 0 0 2 5 0 0

192

B.11: Lake INV08-9b – Raw Diatom Counts (cont’d)

sp1 Interval (cm) borealis Pinnularia major Pinnularia Pinnularia Rhopalodia gibba gibba Rhopalodia valves diatom Total Chrysophyte Scales Cysts Chrysophyte 0-0.25 0 0 0 4 388 0 13 0.5-0.75 0 0 0 0 448 0 5 1-1.25 0 0 0 2 311 0 3 1.5-1.75 0 0 0 2 412 0 8 2-2.25 0 0 0 6 426 0 7 3-3.25 0 0 2 0 357 0 4 4-4.25 0 0 0 0 330 0 3 5-5.25 0 0 0 0 320 0 3 6-6.25 0 0 0 2 309 0 0 7-7.25 0 0 0 0 337 0 4 8-8.25 0 0 0 0 388 0 10 9-9.25 0 0 0 0 314 0 4 10-10.25 0 2 0 0 386 0 4 12-12.25 0 0 0 0 308 0 4 14-14.25 3 0 0 0 343 0 12 16-16.5 0 0 0 0 306 0 4 18-18.5 0 0 0 0 295 0 6

193

B.12: Lake INV08-14a – Raw Diatom Counts

unknown girdle sp1 girdle unknown Interval (cm) acares Achnanthes curtissima Achnanthes didyma Achnanthes exigua Achnanthes gracillima Achnanthes impexiformis Achnanthes lanceolota Achnanthes levanderi Achnanthes marginulata Achnanthes minutissima Achnanthes peterseneii Achnanthes pusilla Achnanthes subatomoides Achnanthes ventralis Achnanthes Achnanthes Amphora inariensis inariensis Amphora libyca Amphora ovalis Amphora pediculus Amphora 0-0.25 5 5 0 0 0 0 0 0 0 15 2 4 0 0 0 0 0 0 0 0.25-0.5 2 2 0 0 0 0 2 0 0 32 2 0 0 0 0 4 0 0 0 0.5-0.75 0 3 0 0 0 0 0 0 1 20 1 0 0 0 0 0 1 0 2 0.75-1.0 0 4 0 0 1 0 10 0 1 18 8 0 0 0 0 0 0 0 0 1-1.25 3 2 0 0 0 0 0 0 1 27 0 0 0 0 0 0 0 0 1 1.5-1.75 0 8 0 0 0 0 1 0 0 13 0 0 0 0 0 0 0 0 0 2-2.25 0 11 0 0 0 0 3 0 0 11 0 2 0 0 0 0 0 0 0 2.5-2.75 2 9 0 3 0 0 0 0 0 0 0 2 0 0 0 0 0 0 1 3-3.25 0 2 0 4 0 0 6 4 0 23 0 8 3 1 0 0 0 2 1 3.5-3.75 3 2 0 2 0 0 2 5 0 13 0 4 0 1 0 0 0 2 0 4-4.25 4 5 0 2 0 0 8 0 0 11 0 4 1 0 0 0 0 0 2 4.5-4.75 1 0 2 3 0 0 1 0 0 12 0 2 0 0 2 0 0 0 4 5-5.25 0 4 2 0 0 0 7 0 0 6 0 0 2 0 0 0 0 0 2 6-6.25 0 1 0 0 0 0 0 0 0 6 0 1 5 0 0 0 0 0 5 7-7.25 0 0 0 1 0 0 8 0 0 4 0 1 0 0 0 0 0 0 0 8-8.25 3 2 0 0 0 0 4 0 0 2 0 0 0 0 0 0 1 0 1 9-9.25 7 5 0 0 0 0 2 0 0 8 0 1 3 0 0 0 0 0 6 10-10.25 6 5 0 0 0 0 13 0 0 12 0 0 3 0 0 0 2 0 11 12-12.25 4 6 0 0 0 0 3 0 0 14 0 6 5 0 0 1 0 0 3 14-14.25 5 5 0 0 0 0 7 0 0 4 0 5 0 0 0 0 2 0 2 16-16.5 7 5 0 0 0 0 15 0 0 12 0 0 9 0 0 5 0 0 5 18-18.5 7 14 0 0 0 0 11 0 0 23 0 1 7 0 0 1 1 0 1 20-20.5 4 3 0 0 0 1 9 0 0 9 0 0 1 0 0 2 0 0 1 22-22.5 15 11 0 0 0 1 9 0 0 9 0 1 8 0 0 0 4 0 0 24-24.5 8 16 0 0 0 2 9 0 0 6 0 0 8 0 0 2 0 0 2 26-26.5 4 3 0 0 0 0 26 0 0 18 0 3 7 0 0 0 3 0 3 28-28.5 3 12 0 0 0 3 12 0 0 19 0 4 4 0 0 0 1 0 0 30-30.5 3 15 0 0 0 0 7 0 0 28 0 7 5 0 0 0 0 0 0 32-32.5 1 6 0 0 0 0 7 0 0 4 0 9 4 0 0 0 0 0 0 34-34.5 6 9 0 0 0 0 2 0 0 8 0 2 2 0 0 0 0 0 1 36-36.5 8 13 0 0 0 0 12 0 0 11 0 5 7 0 0 2 0 0 0

194

B.12: Lake INV08-14a – Raw Diatom Counts (cont’d)

euglypta lemanica nivalis var. v. v.

girdle "huge" Interval (cm) Asterionella formosa ambigua Aulacoseira distans Aulacoseira Caloneis bacillum Cocconeis placentula invisitatus Cyclostephanos tholiformis Cyclostephanos Cyclotella bodanica Cyclotella michiganiana Cyclotella michiganiana Cyclotella pseudostelligera Cyclotella stelligera Cymbella Cymbopleura amphicephala Denticula Diatoma tenuis Diploneis oculata Diploneis parma lunatum Encyonema minutum Encyonema 0-0.25 13 0 0 0 13 10 27 0 8 9 20 0 0 0 0 0 0 0 0 0.25-0.5 20 0 0 0 14 14 28 0 5 0 26 0 0 0 0 0 0 0 0 0.5-0.75 32 0 0 0 8 21 29 0 6 2 13 1 0 0 0 0 1 1 0 0.75-1.0 17 0 0 0 18 20 16 0 7 0 31 0 0 0 0 0 2 0 0 1-1.25 14 0 0 2 10 7 13 0 8 0 34 0 0 0 0 0 0 0 1 1.5-1.75 15 0 0 0 16 0 19 0 3 17 23 0 0 0 0 0 1 0 0 2-2.25 25 0 0 0 7 0 21 0 7 16 28 0 3 0 0 2 0 0 0 2.5-2.75 19 0 0 0 14 2 16 0 6 0 31 0 1 0 1 0 0 0 0 3-3.25 31 0 0 1 14 0 13 0 10 52 23 1 0 4 1 0 0 0 0 3.5-3.75 18 0 0 1 5 0 12 0 8 23 21 0 0 0 1 0 0 0 0 4-4.25 17 0 0 0 9 7 13 0 15 33 11 1 2 0 1 0 0 0 1 4.5-4.75 26 0 0 0 16 0 7 0 11 22 0 0 0 0 0 3 1 3 0 5-5.25 19 0 0 0 11 0 13 0 18 28 3 0 1 0 0 0 0 0 1 6-6.25 26 0 0 0 12 0 4 0 7 14 15 0 1 0 0 1 0 0 0 7-7.25 11 0 0 0 22 2 9 0 8 11 5 0 1 0 0 1 2 0 0 8-8.25 4 0 0 0 9 0 1 0 5 7 4 0 2 0 0 0 0 0 0 9-9.25 9 0 0 0 0 0 0 0 3 4 6 0 4 0 0 1 0 0 0 10-10.25 5 0 3 0 3 0 0 0 5 5 0 0 0 0 0 2 0 0 0 12-12.25 18 0 2 0 4 0 0 2 10 3 0 0 2 0 0 5 0 0 0 14-14.25 20 0 0 2 2 0 0 1 7 4 0 0 3 0 0 3 0 0 0 16-16.5 17 0 0 1 1 0 0 5 2 6 0 0 3 0 0 2 1 0 0 18-18.5 24 0 0 2 2 0 0 3 0 1 0 0 3 0 2 0 2 0 0 20-20.5 3 0 0 4 0 0 0 2 1 1 0 0 2 0 0 1 0 0 0 22-22.5 11 0 0 0 0 0 0 1 2 5 2 0 4 0 0 4 0 0 1 24-24.5 1 0 0 0 0 0 0 1 0 1 1 2 2 0 0 1 0 0 0 26-26.5 13 2 0 0 0 0 0 1 0 3 0 0 1 0 0 1 0 0 0 28-28.5 14 0 0 0 0 0 0 0 1 1 0 0 1 0 0 3 0 0 0 30-30.5 5 10 0 0 1 0 0 0 0 5 0 0 2 0 0 4 0 0 0 32-32.5 5 18 0 0 3 0 0 10 0 5 0 0 1 0 0 0 2 0 0 34-34.5 3 9 0 0 1 0 0 2 0 9 4 0 6 0 0 1 0 0 0 36-36.5 4 7 0 0 4 0 0 3 0 10 6 0 0 0 0 1 2 0 0

195

B.12: Lake INV08-14a – Raw Diatom Counts (cont’d)

leptostauron leptostauron venter v. exigua v.

sp1 "long" Interval (cm) Epithemia Eunotia incisa Eunotia capucina Fragilaria binodis Fragilaria brevistriata Fragilaria construens Fragilaria v. construens Fragilaria leptostauron Fragilaria neoproducta Fragilaria parasitica Fragilaria pinnata Fragilaria pseudoconstruens Fragilaria tenera Fragilaria Fragilaria virescens Frustulia rhomboides Gomphonema acuminatum Gomphonema angustatum Gomphonema parvulum 0-0.25 0 2 0 64 2 11 0 5 0 0 0 62 0 2 0 0 0 0 3 0.25-0.5 0 3 0 42 0 22 0 0 0 2 0 69 0 1 0 0 0 0 6 0.5-0.75 0 2 1 45 0 24 0 0 0 2 0 71 0 0 0 2 1 0 1 0.75-1.0 0 1 2 61 0 18 0 0 3 0 0 51 0 4 0 0 0 0 0 1-1.25 0 3 0 51 0 19 0 0 0 0 0 76 0 11 0 0 0 0 4 1.5-1.75 1 0 0 68 0 13 0 0 0 0 0 96 0 0 0 0 0 0 1 2-2.25 0 5 0 54 0 38 0 0 0 0 0 65 0 9 0 0 0 0 2 2.5-2.75 1 0 0 76 0 21 0 0 0 0 2 94 0 36 1 0 0 0 4 3-3.25 0 0 0 52 0 36 0 2 0 0 2 93 0 13 2 0 2 0 8 3.5-3.75 0 0 0 41 0 24 0 1 0 0 0 74 0 13 0 0 0 5 0 4-4.25 0 1 0 51 0 27 0 9 0 0 0 93 2 11 4 0 0 2 1 4.5-4.75 0 0 0 37 0 23 0 4 5 0 0 92 0 2 2 0 0 3 0 5-5.25 0 1 0 32 0 15 4 15 0 0 0 119 0 0 0 0 0 3 0 6-6.25 0 0 0 24 2 17 4 6 3 0 0 163 0 2 0 0 0 1 0 7-7.25 0 1 0 13 1 20 0 4 6 0 0 250 0 3 0 0 0 0 4 8-8.25 0 0 0 4 0 15 0 10 8 0 0 213 0 3 0 0 0 0 0 9-9.25 0 0 0 13 0 51 0 6 4 0 11 170 0 0 0 0 2 5 0 10-10.25 0 0 0 15 3 58 0 18 6 0 5 189 0 9 0 0 0 3 0 12-12.25 0 0 0 19 7 74 0 7 2 0 19 229 0 10 0 0 0 2 0 14-14.25 0 0 0 20 4 54 0 4 0 0 16 148 0 4 0 0 0 2 0 16-16.5 0 0 0 15 0 58 0 14 0 0 20 187 0 3 0 0 0 6 0 18-18.5 0 0 0 23 0 43 0 7 2 0 22 130 0 0 0 0 0 0 0 20-20.5 0 0 0 2 16 44 0 11 3 0 25 145 0 0 0 0 0 0 0 22-22.5 0 0 0 5 0 70 0 2 3 0 18 220 0 0 0 0 0 0 0 24-24.5 0 0 0 3 0 61 0 5 2 0 7 201 0 0 0 0 0 0 0 26-26.5 0 1 0 6 3 69 0 9 0 3 22 137 0 0 0 0 0 2 0 28-28.5 0 0 0 8 0 42 0 16 0 3 0 175 0 0 0 0 0 1 0 30-30.5 0 0 0 0 0 44 0 9 0 1 22 160 0 0 0 0 0 0 0 32-32.5 0 0 0 4 0 54 0 5 0 0 9 181 0 0 0 0 0 0 0 34-34.5 0 0 0 4 1 50 0 9 0 0 7 224 0 0 0 0 0 0 0 36-36.5 0 0 0 4 5 38 0 6 2 7 21 197 0 0 0 0 0 0 0

196

B.12: Lake INV08-14a – Raw Diatom Counts (cont’d)

Interval (cm) Gyrosigma acuminatum Navicula cocconeiformis Navicula cryptocephala Navicula difficillima Navicula disjuncta Navicula laevissima Navicula menisculus Navicula peterseneii Navicula pseudoscutiformis Navicula pupula Navicula radiosa Navicula submuralis Navicula subtillissima Navicula utermoehlii Navicula vitiosa Nitzschia acicularis Nitzschia gracilis Nitzschia palea Nitzschia perminuta 0-0.25 0 0 4 0 4 0 0 2 0 1 0 0 0 0 1 0 0 7 0 0.25-0.5 0 0 12 0 6 0 0 0 0 0 0 0 0 0 2 2 0 9 4 0.5-0.75 1 0 8 1 1 1 0 0 0 0 0 1 1 0 0 2 0 9 5 0.75-1.0 0 0 7 0 1 0 0 0 0 0 0 0 1 0 0 0 0 15 3 1-1.25 0 0 4 0 2 0 0 0 0 0 0 1 0 0 0 0 0 4 0 1.5-1.75 0 0 7 0 1 0 0 0 0 0 0 0 0 0 3 0 0 0 2 2-2.25 0 0 0 0 3 0 0 0 0 0 0 0 1 0 7 0 0 4 0 2.5-2.75 0 0 5 0 1 7 0 0 0 0 0 0 0 0 3 0 0 6 3 3-3.25 0 0 4 0 3 1 0 0 2 0 0 0 0 0 4 0 4 10 0 3.5-3.75 0 0 6 0 0 3 2 0 0 2 0 1 0 0 4 2 0 6 1 4-4.25 0 0 3 0 4 0 2 0 0 1 0 2 0 0 2 3 0 11 3 4.5-4.75 1 0 2 0 2 0 0 0 0 0 0 2 0 0 0 0 4 5 4 5-5.25 0 0 1 0 8 2 2 0 0 0 0 3 2 0 2 0 0 5 4 6-6.25 1 0 2 1 3 0 0 0 0 0 0 5 0 0 8 1 0 5 1 7-7.25 0 0 1 1 1 1 0 0 0 0 0 5 0 0 7 0 0 2 0 8-8.25 0 0 0 0 6 5 0 0 0 3 0 3 0 0 0 2 0 0 0 9-9.25 0 0 0 2 0 0 0 0 0 0 0 0 0 3 3 2 0 4 0 10-10.25 1 0 0 1 2 1 0 0 0 0 1 3 0 2 10 0 0 6 0 12-12.25 0 1 4 7 2 1 0 0 1 0 3 2 0 2 4 0 3 2 4 14-14.25 0 1 6 3 5 0 0 0 1 2 0 6 0 1 6 0 1 2 0 16-16.5 0 1 2 4 5 2 0 0 1 1 4 0 0 0 11 0 0 2 0 18-18.5 1 0 3 2 3 1 0 0 2 0 0 7 0 3 8 0 2 3 2 20-20.5 0 0 5 5 2 0 0 0 0 0 1 3 0 1 16 0 0 0 2 22-22.5 0 0 3 13 2 0 0 0 0 0 0 4 0 1 16 0 0 3 5 24-24.5 0 0 7 7 0 0 0 0 0 0 0 6 0 1 14 0 0 0 0 26-26.5 1 0 5 3 1 0 0 0 2 3 1 5 0 0 22 0 0 4 1 28-28.5 0 0 3 6 1 0 0 0 0 2 0 6 1 0 40 0 0 2 2 30-30.5 0 0 2 0 0 1 0 0 0 0 0 5 0 0 16 0 0 4 0 32-32.5 0 0 7 0 0 0 0 0 1 0 0 3 0 1 15 1 0 0 3 34-34.5 0 1 12 1 4 0 0 0 0 1 2 5 0 0 9 0 0 4 8 36-36.5 0 3 5 1 7 3 0 0 0 0 0 11 0 0 14 0 0 3 6

197

B.12: Lake INV08-14a – Raw Diatom Counts (cont’d)

strain IV

sp1 "huge" unknown girdle sp1 sp1 girdle unknown sp1 unknown Totaldiatom valves Chrysophyte Scales Cysts Chrysophyte Plates Protozoan Sponge Spicules Interval (cm) Nitzschia borealis Pinnularia gibba Pinnularia microstaunton Pinnularia nodosa Pinnularia Pinnularia Stauroneis anceps anceps Stauroneis Stauroneis smithii wislouchii Stauroneis Tabellaria fenestrata Tabellaria floculosa 0-0.25 0 0 0 0 0 0 1 0 0 0 1 0 0 303 13 110 0 1 0.25-0.5 0 0 0 0 0 0 0 0 0 0 0 0 0 331 17 151 3 2 0.5-0.75 2 0 0 0 0 1 2 0 0 0 0 0 0 326 23 139 0 0 0.75-1.0 0 1 0 0 0 0 0 0 0 0 0 0 0 321 12 119 0 3 1-1.25 0 0 0 0 0 0 6 0 0 0 0 0 0 304 12 80 0 0 1.5-1.75 0 6 0 0 4 0 1 0 0 0 0 0 0 319 7 91 0 0 2-2.25 0 0 0 0 0 0 0 0 0 0 0 0 0 324 10 122 0 0 2.5-2.75 0 0 0 0 0 0 0 0 0 0 0 0 0 367 8 182 0 0 3-3.25 0 0 0 0 0 0 1 1 0 0 0 0 6 450 8 205 0 0 3.5-3.75 0 0 0 0 0 0 1 0 0 0 0 0 1 310 4 128 0 0 4-4.25 0 0 0 0 0 0 1 0 0 0 0 6 0 386 5 223 0 0 4.5-4.75 0 2 0 0 0 0 1 0 0 0 0 0 0 307 5 163 0 0 5-5.25 0 0 0 0 0 2 0 0 0 0 0 0 0 337 6 163 0 0 6-6.25 0 0 0 0 0 0 1 0 0 0 0 0 0 348 3 201 0 0 7-7.25 0 0 0 0 0 0 1 2 0 0 0 0 0 409 6 313 0 0 8-8.25 0 0 0 0 0 0 0 0 0 0 0 2 0 319 1 152 0 0 9-9.25 0 0 0 0 0 0 0 0 0 0 0 0 2 337 2 109 0 0 10-10.25 0 0 0 0 0 0 0 0 2 0 0 0 4 414 3 141 0 0 12-12.25 0 0 1 0 0 0 2 1 0 0 0 0 0 497 9 157 0 0 14-14.25 0 0 0 1 0 0 0 0 0 0 0 0 0 359 6 80 0 0 16-16.5 0 7 0 1 0 0 0 0 0 0 0 0 0 440 1 87 0 0 18-18.5 0 0 0 0 0 0 0 0 0 0 0 0 2 371 0 83 0 0 20-20.5 0 0 0 0 0 0 0 0 0 0 0 0 0 325 0 107 0 0 22-22.5 0 2 0 0 0 0 2 0 0 0 0 0 0 457 0 80 0 0 24-24.5 0 0 0 0 0 0 0 0 0 2 0 0 0 378 0 37 0 0 26-26.5 0 0 0 0 0 0 0 0 0 0 2 0 0 390 0 96 0 0 28-28.5 0 0 0 0 0 0 2 0 0 0 0 0 0 388 0 84 0 0 30-30.5 0 0 0 0 0 0 0 0 0 0 0 0 0 356 0 74 0 0 32-32.5 0 2 0 0 0 0 3 0 0 0 0 0 0 364 0 92 0 0 34-34.5 0 1 0 2 0 0 0 0 0 0 0 0 0 410 0 78 0 0 36-36.5 0 0 0 0 0 0 2 0 0 0 0 0 0 430 0 91 0 0

198

B.13: Lake INV08-14b – Raw Diatom Counts

euglypta var. . lemanica . v unknown girdle sp1 girdle unknown Interval (cm) acares Achnanthes exigua Achnanthes gracillima Achnanthes impexiformis Achnanthes lanceolota Achnanthes marginulata Achnanthes minutissima Achnanthes pusilla Achnanthes Achnanthes Amphora inariensis inariensis Amphora libyca Amphora pediculus Amphora Asterionella formosa Caloneis bacillum Cocconeis placentula Cyclotella bodanica Cyclotella michiganiana Cyclotella ocellata Cyclotella pseudostelligera 0-0.25 0 0 0 0 0 0 0 0 2 9 0 0 2 0 1 0 0 252 15 0.25-0.5 0 0 0 0 0 0 5 0 0 3 0 0 6 0 4 0 0 298 7 0.5-0.75 3 0 1 0 0 0 7 0 0 0 0 2 19 0 0 0 1 225 28 0.75-1.0 0 0 0 0 0 0 0 0 0 0 0 0 12 0 4 0 14 202 0 1-1.25 0 1 0 0 0 0 6 3 0 8 0 0 46 0 1 1 5 47 57 2-2.25 3 4 0 3 4 0 10 0 0 16 1 6 4 2 0 8 1 8 7 3-3.25 3 2 0 0 2 0 0 0 0 14 0 2 0 0 0 0 0 2 1 4-4.25 0 0 0 0 0 3 0 0 0 18 0 0 6 0 0 0 0 0 3 5-5.25 0 0 0 0 2 0 0 1 0 8 0 0 0 0 2 0 0 1 0 6-6.25 0 0 0 0 0 0 0 0 0 15 0 0 10 0 0 0 0 0 0 7-7.25 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8-8.25 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9-9.25 0 0 0 0 0 0 10 0 0 0 0 0 0 0 10 0 0 20 0

leptostauron leptostauron pumila venter v.

sp1 girdle Interval (cm) Cyclotella stelligera Cyclotella tripartia Cymbella naviculiformis Cymbella Cymbopleura amphicephala Cymbopleura amphicephala Diploneis elliptica Diploneis oblongella Diploneis oculata Diploneis parma Epithemia Eunotia incisa capucina Fragilaria brevistriata Fragilaria construens Fragilaria v. construens Fragilaria v. construens Fragilaria leptostauron Fragilaria neoproducta Fragilaria parasitica Fragilaria 0-0.25 0 0 0 0 0 0 0 0 0 0 1 20 25 0 2 2 1 0 0 0.25-0.5 0 4 1 0 0 0 0 0 0 0 0 0 9 2 1 0 0 0 0 0.5-0.75 0 0 0 2 1 0 2 0 0 0 0 0 8 0 4 0 0 0 0 0.75-1.0 0 0 0 0 4 0 0 4 2 0 0 14 10 0 0 8 0 0 0 1-1.25 4 0 0 0 1 2 0 2 6 0 0 17 17 18 0 12 0 0 0 2-2.25 0 0 0 0 0 3 0 8 6 2 0 10 51 30 0 28 7 7 2 3-3.25 0 0 0 0 4 1 0 1 4 0 0 0 46 27 0 22 4 0 1 4-4.25 0 0 0 0 0 0 0 0 9 0 3 0 90 0 0 12 6 0 0 5-5.25 0 0 0 0 0 0 0 0 0 0 3 2 46 7 0 5 2 0 1 6-6.25 0 0 0 0 0 0 0 0 6 0 5 0 20 0 0 0 0 0 0 7-7.25 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8-8.25 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9-9.25 0 0 0 0 0 0 0 0 0 0 0 0 40 0 0 0 0 0 0

199

B.13: Lake INV08-14b – Raw Diatom Counts (cont’d)

Interval (cm) pinnata Fragilaria tenera Fragilaria Gomphonema parvulum Gyrosigma acuminatum Navicula cocconeiformis Navicula cryptocephala Navicula difficillima Navicula disjuncta Navicula halophila Navicula laevissima Navicula menisculus Navicula pseudoventralis Navicula pupula Navicula submuralis Navicula utermoehlii Navicula vitiosa Nitzschia acicularis Nitzschia palea Nitzschia perminuta 0-0.25 40 0 0 0 0 0 1 0 1 0 1 0 0 0 0 1 1 3 4 0.25-0.5 4 15 0 0 1 1 0 0 0 0 0 0 0 0 0 0 9 0 2 0.5-0.75 25 34 2 0 0 5 0 0 0 0 0 1 0 7 1 0 6 9 5 0.75-1.0 16 30 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 6 4 1-1.25 80 18 1 2 0 3 0 1 3 0 0 0 1 9 2 3 0 21 9 2-2.25 163 0 0 4 0 7 0 1 3 0 1 0 0 2 0 6 0 1 4 3-3.25 134 0 0 4 1 2 0 0 0 0 0 0 0 1 0 1 0 0 2 4-4.25 156 0 0 9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5-5.25 161 0 0 11 0 0 0 0 0 1 0 0 0 0 1 0 2 1 0 6-6.25 228 0 0 10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7-7.25 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8-8.25 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9-9.25 200 0 0 25 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

"huge" Interval (cm) Nitzschia tubicola Nitzschia borealis Pinnularia anceps Stauroneis wislouchii Stauroneis Surirella tiny sp1 girdle unknown sp2 girdle unknown sp1 unknown valves diatom Total Chrysophyte Scales Cysts Chrysophyte Plates Protozoan Phytoliths Sponge Spicules 0-0.25 2 0 0 0 0 0 0 0 0 386 5 38 0 0 0 0.25-0.5 1 0 0 0 0 0 0 0 0 373 16 22 0 0 0 0.5-0.75 0 2 0 0 0 0 0 0 0 400 19 46 0 0 0 0.75-1.0 0 0 4 0 0 0 0 0 0 336 8 40 4 0 0 1-1.25 0 1 0 0 4 1 2 4 4 423 11 64 1 0 0 2-2.25 1 5 0 0 0 2 0 2 0 433 1 59 3 0 0 3-3.25 0 0 0 2 0 0 0 0 0 283 0 16 0 0 0 4-4.25 0 0 0 0 0 0 0 0 0 315 0 63 0 0 0 5-5.25 0 0 0 0 0 0 0 0 0 257 1 100 0 0 6 6-6.25 0 0 0 0 0 0 0 0 0 294 0 115 0 3 0 7-7.25 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8-8.25 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9-9.25 0 0 0 0 0 0 0 0 0 305 0 55 0 0 0

200

B.14: Lake INV08-36a – Raw Diatom Counts

. nivalis v

unknown sp1 unknown sp1 Interval (cm) acares Achnanthes carissima Achnanthes curtissima Achnanthes impexiformis Achnanthes lacus-vulcani Achnanthes lanceolota Achnanthes levanderi Achnanthes marginulata Achnanthes minutissima Achnanthes pusilla Achnanthes subatomoides Achnanthes Achnanthes Amphora libyca libyca Amphora pediculus Amphora Asterionella formosa ambigua Aulacoseira distans Aulacoseira Brachysira Caloneis bacillum 0-0.25 0 0 9 2 0 0 0 0 15 7 0 5 0 0 0 0 0 8 0 0.25-0.5 2 0 0 2 0 0 0 0 2 1 0 0 0 0 0 0 0 3 2 0.5-0.75 0 0 10 0 0 0 0 0 11 1 2 0 0 0 0 0 0 8 0 1-1.25 0 0 2 2 0 0 0 0 8 0 5 0 0 0 0 0 0 5 0 1.5-1.75 0 0 2 2 0 0 0 0 4 3 2 0 0 0 0 0 0 1 3 2-2.25 0 0 8 0 0 0 1 3 2 1 4 0 0 0 1 0 0 2 0 3-3.25 0 0 0 0 0 0 0 1 0 3 7 0 0 0 0 0 0 0 0 4-4.25 0 1 5 1 3 0 0 2 1 1 2 0 0 0 0 3 0 0 0 5-5.25 0 0 0 1 7 0 0 0 0 0 3 0 2 0 2 0 0 0 0 6-6.25 0 0 8 0 6 0 0 0 2 1 2 0 3 0 2 3 0 0 0 7-7.25 0 0 2 0 2 0 0 0 2 1 0 0 3 0 1 13 0 0 0 8-8.25 0 0 2 0 0 4 0 0 4 5 0 0 2 0 2 7 0 0 0 10-10.25 0 0 1 1 0 3 0 0 6 5 0 0 1 0 1 16 0 1 1 12-12.25 3 0 2 0 1 1 0 2 2 6 0 0 5 0 15 25 2 0 1 14-14.25 0 0 2 0 0 0 0 0 7 3 1 0 1 0 16 103 0 0 5 16-16.25 0 0 2 3 2 0 0 0 0 1 0 0 1 2 17 96 5 2 0 18-18.25 1 0 0 4 4 0 0 0 2 1 2 0 0 0 23 38 2 1 0 20-20.25 1 0 0 3 0 0 1 0 0 0 3 0 3 0 5 14 0 0 1 22-22.25 0 0 0 0 0 5 0 0 0 0 0 0 6 0 1 1 0 4 1 26-26.25 0 0 0 0 0 2 2 0 1 4 3 0 0 1 7 12 0 0 1

201

B.14: Lake INV08-36a – Raw Diatom Counts (cont’d)

euglypta lemanica var. v.

sp1 sp4 sp3 sp2 sp1 Fragilaria capucina capucina Fragilaria binodis Fragilaria Eunotia Eunotia Eunotia Eunotia Eunotia Eunotia Interval (cm) Cocconeis placentula invisitatus Cyclostephanos tholiformis Cyclostephanos Cyclotella bodanica Cymbella Diploneis oculata Diploneis parma herbridicum Encyonema lunatum Encyonema minutum Encyonema faba Eunotia Eunotia incisa Eunotia serra Eunotia 0-0.25 0 0 0 0 2 0 0 0 8 0 0 4 0 37 19 3 5 37 4 0.25-0.5 0 0 0 0 0 0 0 1 0 0 0 12 1 0 7 0 0 19 0 0.5-0.75 0 0 0 0 0 0 0 0 4 0 3 0 0 18 15 3 0 25 0 1-1.25 0 0 0 0 0 0 0 0 4 0 12 0 0 6 20 0 2 45 0 1.5-1.75 0 0 1 0 0 0 0 0 1 0 14 0 0 0 25 3 5 27 0 2-2.25 0 0 0 0 1 0 0 0 2 0 17 0 2 7 15 0 6 30 0 3-3.25 0 1 0 0 0 0 0 0 1 0 4 0 1 0 6 0 6 2 0 4-4.25 1 0 0 0 1 0 0 0 1 0 11 3 0 0 2 0 0 2 0 5-5.25 1 0 0 0 0 0 0 0 1 0 6 0 0 0 1 0 1 3 0 6-6.25 1 0 0 0 0 0 0 0 1 0 3 3 0 0 4 0 0 2 0 7-7.25 2 0 0 0 2 0 0 0 1 0 4 4 3 0 1 0 0 1 4 8-8.25 2 0 0 0 2 0 0 0 1 0 5 3 0 0 0 0 0 5 0 10-10.25 0 0 0 0 0 0 0 0 0 0 4 6 0 0 0 0 2 4 0 12-12.25 0 0 0 0 1 0 0 0 2 0 8 0 0 0 4 0 4 4 0 14-14.25 3 0 0 0 0 0 0 1 3 1 4 1 3 0 0 0 0 4 0 16-16.25 1 0 0 0 0 0 0 0 2 0 0 5 1 0 0 0 0 4 0 18-18.25 0 0 0 0 0 1 0 0 0 0 4 3 0 0 3 0 0 0 0 20-20.25 1 0 0 1 0 1 3 0 0 3 9 0 0 0 2 0 1 0 0 22-22.25 0 0 0 0 0 0 0 0 4 0 15 9 0 0 4 0 0 0 0 26-26.25 2 0 0 1 0 0 0 0 1 0 7 0 0 0 0 0 0 0 0

202

B.14: Lake INV08-36a – Raw Diatom Counts (cont’d)

leptostauron leptostauron venter v. exigua trigona trigona v. v. Interval (cm) brevistriata Fragilaria construens Fragilaria v. construens Fragilaria var. "triangle" construens Fragilaria leptostauron Fragilaria pinnata Fragilaria pinnata Fragilaria tenera Fragilaria Fragilaria virescens Frustulia rhomboides Gomphonema acuminatum Gomphonema angustatum Gomphonema parvulum Gyrosigma acuminatum Navicula cryptocephala Navicula difficillima Navicula disjuncta Navicula halophila Navicula laevissima 0-0.25 53 0 0 0 0 23 0 9 11 0 0 0 1 0 0 13 9 61 0 0.25-0.5 2 0 4 0 0 0 0 0 14 2 0 0 0 0 0 0 0 17 0 0.5-0.75 25 0 0 0 0 31 2 8 20 2 1 0 0 0 4 0 5 46 1 1-1.25 22 0 2 0 0 13 0 0 9 5 0 0 1 0 1 0 2 49 1 1.5-1.75 18 0 0 0 0 16 0 1 5 4 0 0 0 0 3 0 2 83 3 2-2.25 25 0 3 0 0 19 0 3 10 5 0 0 3 0 0 1 5 78 2 3-3.25 45 0 12 0 0 132 7 2 29 7 0 0 0 0 2 0 12 27 4 4-4.25 68 4 8 0 0 121 1 1 27 0 0 3 1 0 0 1 5 2 1 5-5.25 65 0 45 0 0 108 3 0 27 2 0 0 0 0 0 0 4 0 0 6-6.25 59 0 98 3 0 109 0 0 19 0 0 0 3 0 0 1 9 0 0 7-7.25 38 0 103 0 0 61 2 0 29 6 1 2 1 0 0 0 0 0 2 8-8.25 29 0 139 0 0 75 3 0 35 0 0 0 1 0 0 0 4 0 3 10-10.25 24 0 127 0 0 47 2 0 31 3 1 0 2 0 1 0 3 0 2 12-12.25 9 0 101 0 0 47 6 0 30 0 0 0 0 0 3 0 0 0 1 14-14.25 3 0 58 0 2 46 0 0 21 3 0 2 0 0 0 0 6 0 0 16-16.25 6 0 71 0 0 38 0 0 28 3 0 0 1 0 1 0 5 0 0 18-18.25 0 0 91 0 2 65 0 0 36 4 0 0 0 0 1 2 9 0 0 20-20.25 7 0 107 0 2 41 0 0 44 6 0 0 5 2 4 0 6 0 0 22-22.25 1 0 123 0 0 49 0 0 39 5 0 0 1 0 2 0 5 3 0 26-26.25 3 0 92 0 0 73 0 0 23 2 0 0 4 0 2 0 0 0 0

203

B.14: Lake INV08-36a – Raw Diatom Counts (cont’d)

sp1 sp1 sp1 Interval (cm) Navicula mediocris Navicula menisculus Navicula pseudoscutiformis Navicula pseudoventralis Navicula pupula Navicula radiosa Navicula seminulum Navicula submuralis Navicula utermoehlii Navicula vitiosa Navicula Neidium Nitzschia acicularis Nitzschia gracilis Nitzschia palea Nitzschia perminuta Nitzschia brauniana Pinnularia gibba Pinnularia 0-0.25 4 0 0 0 0 5 0 2 0 2 1 0 6 0 22 7 8 0 0 0.25-0.5 6 0 0 0 0 0 0 0 0 0 0 0 2 0 6 1 0 2 0 0.5-0.75 4 0 0 0 0 0 0 0 0 12 0 0 0 5 6 6 0 12 0 1-1.25 14 0 0 0 0 3 0 0 0 14 0 0 0 6 6 8 0 16 0 1.5-1.75 9 0 0 0 0 2 0 0 0 8 0 0 0 8 2 0 0 14 0 2-2.25 9 0 0 0 0 0 0 0 0 5 0 0 2 3 2 6 0 4 0 3-3.25 6 1 0 0 3 2 0 0 0 12 0 0 0 4 1 0 0 3 0 4-4.25 7 0 0 0 3 0 0 0 0 6 0 0 0 1 1 0 0 0 0 5-5.25 3 0 0 0 0 0 0 0 0 4 0 0 0 2 2 0 0 0 0 6-6.25 0 0 1 0 4 0 8 0 0 0 0 0 0 0 2 0 0 0 0 7-7.25 4 0 1 0 5 1 4 0 0 3 0 0 0 0 1 0 0 7 2 8-8.25 2 0 0 0 2 0 8 0 1 2 0 0 0 0 0 4 0 3 2 10-10.25 3 0 0 0 3 0 2 0 0 2 0 0 0 0 0 1 0 7 2 12-12.25 0 0 0 0 1 0 4 0 3 12 0 0 0 0 0 2 0 3 2 14-14.25 4 0 0 0 2 0 0 0 0 4 0 0 0 0 0 0 0 7 3 16-16.25 0 0 0 0 1 0 0 0 2 5 0 0 0 0 0 0 0 4 0 18-18.25 1 0 0 0 1 0 0 0 4 2 0 0 0 0 0 0 0 0 0 20-20.25 2 0 0 0 5 0 0 0 0 1 0 1 0 0 0 0 0 3 0 22-22.25 0 0 0 0 8 0 0 0 0 4 0 0 0 0 3 0 0 6 0 26-26.25 0 0 0 1 0 0 0 0 0 6 0 0 0 0 0 3 0 2 0

204

B.14: Lake INV08-36a – Raw Diatom Counts (cont’d)

strain III

strain IV

sp1 sp2 girdle sp2 sp3 sp1 tiny Interval (cm) major Pinnularia microstaunton Pinnularia nodosa Pinnularia Pinnularia Pinnularia Pinnularia Pinnularia Pinnularia Tabellaria quadriseptata sp3 unknown sp2 unknown sp1 unknown valves diatom Total Rhopalodia gibba gibba Rhopalodia anceps Stauroneis phoenicenteron Stauroneis Stauroneis Surirella Tabellaria fenestrata Tabellaria flocculosa Tabellaria floculosa 0-0.25 0 0 0 1 7 2 0 2 0 2 0 6 0 47 0 0 0 0 469 0.25-0.5 0 1 0 0 0 0 0 0 0 0 0 5 0 19 0 0 0 0 133 0.5-0.75 0 0 0 0 0 0 0 1 3 0 0 0 3 25 0 0 0 0 322 1-1.25 0 0 0 0 0 0 0 0 0 0 0 0 4 30 1 0 0 0 318 1.5-1.75 0 0 2 0 0 0 0 0 0 0 0 0 10 31 3 0 0 0 317 2-2.25 0 12 0 0 0 0 0 2 1 0 0 0 10 24 3 0 1 1 341 3-3.25 0 6 0 0 0 0 0 4 0 0 0 0 4 10 7 0 2 0 376 4-4.25 0 1 0 0 0 0 0 7 0 0 0 0 4 10 3 0 1 0 327 5-5.25 0 3 2 0 0 0 0 3 0 0 0 0 1 9 0 1 0 0 312 6-6.25 0 1 0 0 0 0 0 10 1 0 0 0 4 10 0 0 3 0 386 7-7.25 0 1 1 0 0 0 0 1 1 0 1 0 2 5 0 0 0 0 331 8-8.25 0 11 0 0 0 0 0 4 1 0 0 0 8 11 0 0 0 0 392 10-10.25 0 1 0 0 0 0 0 6 0 0 1 0 3 14 0 0 0 0 340 12-12.25 0 7 1 0 0 0 1 1 0 0 0 0 4 15 0 0 0 0 341 14-14.25 1 3 0 0 0 0 0 1 0 0 0 0 2 7 0 0 0 0 333 16-16.25 0 1 0 0 0 0 0 2 0 0 0 0 0 5 0 0 0 0 317 18-18.25 1 1 0 0 0 0 0 2 0 0 0 0 0 9 0 0 0 0 320 20-20.25 5 2 0 0 0 0 0 1 0 0 0 0 1 11 0 0 0 0 308 22-22.25 1 5 0 0 0 0 0 6 1 0 0 0 1 17 0 0 0 0 330 26-26.25 2 0 1 0 0 0 0 2 0 0 0 0 5 4 0 0 0 0 269

205

B.14: Lake INV08-36a – Raw Diatom Counts (cont’d)

Interval (cm) Chrysophytte Scales Cysts Chrysophyte Plates Protozoan Phytoliths Sponge Spicules 0-0.25 34 205 3 0 0 0.25-0.5 5 79 0 0 0 0.5-0.75 16 189 0 0 0 1-1.25 8 156 0 0 0 1.5-1.75 8 137 0 0 0 2-2.25 8 183 1 0 0 3-3.25 2 83 0 0 0 4-4.25 0 48 0 0 0 5-5.25 0 42 0 0 0 6-6.25 0 43 0 0 0 7-7.25 0 47 1 0 2 8-8.25 0 43 1 0 0 10-10.25 0 95 1 0 0 12-12.25 0 160 2 0 0 14-14.25 0 195 1 0 0 16-16.25 0 97 0 0 0 18-18.25 0 112 1 0 0 20-20.25 0 145 2 0 0 22-22.25 0 87 1 0 0 26-26.25 0 74 0 1 1

206

B.15: Lake INV08-36b – Raw Diatom Counts

. Euglypta Euglypta . var Interval (cm) acares Achnanthes carissima Achnanthes didyma Achnanthes exigua Achnanthes impexiformis Achnanthes lanceolota Achnanthes minutissima Achnanthes pusilla Achnanthes subatomoides Achnanthes ventralis Achnanthes inariensis Amphora libyca Amphora Caloneis bacillum Cocconeis placentula Cyclotella bodanica v. Lemanica v. Cyclotella bodanica Cyclotella michiganiana Cyclotella pseudostelligera Cymbopleura amphicephala Diatoma tenuis 0-0.25 1 0 0 0 0 0 7 8 0 6 8 3 0 3 7 3 102 3 0 0.5-0.75 1 0 0 0 0 3 5 8 0 1 12 8 2 2 3 2 115 1 0 1.0-1.25 0 0 0 2 1 1 10 2 2 0 8 8 0 0 2 1 89 1 12 2.0-2.25 4 0 0 0 0 0 10 6 0 0 20 4 0 8 2 0 64 2 0 2.5-2.75 4 0 0 4 0 14 0 16 0 0 12 4 0 4 4 0 22 0 0 3.0-3.25 0 1 1 5 0 5 3 2 0 2 13 0 0 4 3 3 32 0 0

Interval (cm) Diploneis elliptica Diploneis oblongella Diploneis oculata Diploneis parma Epithemia sp1 capucina Fragilaria brevistriata Fragilaria construens Fragilaria pinnata Fragilaria tenera Fragilaria Exigua virescens v. Fragilaria Gomphonema parvulum Gyrosigma acuminatum Navicula cincta Navicula cocconeiformis Navicula cryptocephala Navicula disjuncta Navicula laevissima Navicula menisculus 0-0.25 0 0 0 1 0 13 0 2 18 15 0 10 20 0 1 5 4 0 6 0.5-0.75 0 0 4 0 1 19 7 0 41 4 0 2 27 0 2 8 4 0 1 1.0-1.25 2 2 3 3 0 15 10 0 55 8 0 1 21 4 0 7 6 1 8 2.0-2.25 0 0 6 0 0 8 4 0 80 4 0 0 54 0 0 0 8 0 8 2.5-2.75 0 0 18 0 0 0 12 0 54 4 0 0 82 0 4 14 6 0 0 3.0-3.25 0 0 12 1 0 8 4 0 57 4 0 4 64 0 4 27 6 0 8

207

B.15: Lake INV08-36b – Raw Diatom Counts (cont’d)

Interval (cm) Navicula pupula Navicula radiosa Navicula seminulum Navicula subtillissima Navicula utermoehlii Navicula vitiosa Nitzschia acicularis Nitzschia gracilis Nitzschia palea Nitzschia perminuta borealis Pinnularia brauniana Pinnularia anceps Stauroneis phoenicenteron Stauroneis Stauroneis smithii strain IV Tabellaria floculosa Total Diatom Valves Chrysophyte Scales Cysts Chrysophyte 0-0.25 0 1 2 3 0 0 0 0 12 10 19 0 19 4 0 2 318 1 32 0.5-0.75 2 0 2 0 0 3 0 0 0 2 23 0 12 0 0 0 327 0 26 1.0-1.25 0 0 0 0 0 1 2 0 16 3 28 0 6 2 2 0 345 0 39 2.0-2.25 0 0 0 2 0 0 0 0 6 10 12 6 8 0 0 0 336 0 30 2.5-2.75 0 0 0 0 0 0 0 0 4 22 4 14 6 0 0 328 0 34 3.0-3.25 0 0 1 0 5 0 0 6 0 10 18 0 11 0 4 0 328 0 41

208

B.16: Lake INV09-I20 – Raw Diatom Counts

. euglypta . var Interval (cm) acares Achnanthes curtissima Achnanthes exigua Achnanthes minutissimum Achnanthidium inariensis Amphora libyca Amphora Asterionella formosa Caloneis bacillum Cavinula cocconeiformis Cavinula pseudoscutiformis Cocconeis placentula tholiformis Cyclostephanos Cymbopleura amphicephala Denticula keutzingii Diatoma tenue Diploneis elliptica Diploneis oculata minutum Encyonema Epithemia turgida 0-0.25 2 12 11 1 2 8 79 4 2 0.5-0.75 1 14 2 2 2 4 69 3 1 1.0-1.25 3 11 18 3 1 2 60 4 2.0-2.25 2 10 11 6 9 63 2 1 3.0-3.25 1 3 7 1 1 6 62 3 4.0-4.25 2 4 1 2 2 5 2 28 1 1 1 1 5.0-5.25 2 8 5 13 2 2 1 6.0-6.25 14 1 6 2 1 7.0-7.25 2 7 1 2 1 3 1 2 1 8.0-8.25 4 2 7 1 5 3 1 9.0-9.25 5 3 7 2 1 3 2 2 1 1 11.0-11.25 8 4 1 5 7 1 13.0-13.25 2 2 4 2 2 2 1 15.0-15.5 1 1 11 2 1 3 1 9 17.0-17.5 6 13 1 3 2 1 19.0-19.5 2 16 2 1 4 1 1 23.0-23.5 4 11 2 1 4 5 27.0-27.5 2 17 1 2 5 2 4 3 2 31.0-31.5 11 1 10 1 1 2 35.0-35.5 15 5 2 6 4 1 37.5-38.0 14 2 5

209

B.16: Lake INV09-I20 – Raw Diatom Counts (cont’d)

Interval (cm) faba Eunotia Eunotia incisa capucina Fragilaria tenera Fragilaria neoproducta Fragilariforma Fragilariforma virescens Gomphonema acuminatum Gomphonema angustatum Gyrosigma acuminatum Navicula cryptocephala Navicula difficillima Navicula pseudoarvensis Navicula submuralis Navicula subtillissima Navicula utermoehlii Navicula vitiosa Nitzschia acicularis Nitzschia palea Nitzschia perminuta 0-0.25 13 2 9 2 1 14 2 6 0.5-0.75 1 3 10 2 3 4 17 4 8 1.0-1.25 4 10 3 9 1 9 2 1 2.0-2.25 4 1 2 1 11 4 4 3.0-3.25 4 7 11 1 1 6 2 5 9 7 4.0-4.25 6 4 1 4 2 5 5.0-5.25 1 2 7 2 6.0-6.25 1 2 1 8 7.0-7.25 2 1 1 2 1 4 25 2 8.0-8.25 6 1 2 14 9.0-9.25 4 2 2 1 1 11 2 2 11.0-11.25 2 1 1 1 31 13.0-13.25 8 3 3 13 15.0-15.5 1 1 2 1 2 2 17.0-17.5 1 3 5 2 4 1 19.0-19.5 1 2 1 1 1 1 23.0-23.5 1 1 2 27.0-27.5 2 3 2 3 1 1 1 2 31.0-31.5 1 7 6 2 2 35.0-35.5 1 1 4 1 1 37.5-38.0 4 3 1 5

210

B.16: Lake INV09-I20 – Raw Diatom Counts (cont’d)

Interval (cm) Nupela impexiformis borealis Pinnularia brauniana Pinnularia major Pinnularia nodosa Pinnularia lanceolatum Planothidium Psammothidium chlidanos Psammothidium didymum subatomoides Psammothidium brevistriata Pseudostaurosira parasitica Pseudostaurosira gibba Rhopalodia Rossithidium pusillum disjuncta Sellaphora laevissima Sellaphora pupula Sellaphora seminulum Sellaphora anceps Stauroneis phoenicenteron Stauroneis 0-0.25 6 1 12 1 2 0.5-0.75 11 8 11 6 3 4 1.0-1.25 16 16 2 2.0-2.25 9 5 15 3 3 1 3.0-3.25 14 3 22 5 1 2 1 4.0-4.25 14 7 10 3 5 1 5.0-5.25 9 3 5 3 2 1 6.0-6.25 1 2 1 17 1 13 1 4 2 7.0-7.25 1 1 11 8 6 2 3 3 2 1 8.0-8.25 8 9 12 4 4 1 9.0-9.25 14 5 13 1 7 7 11.0-11.25 1 1 10 12 10 1 5 6 13.0-13.25 12 2 6 3 2 15.0-15.5 24 3 13 1 17.0-17.5 16 3 2 6 2 2 1 19.0-19.5 1 14 3 4 1 1 23.0-23.5 13 6 9 1 2 2 27.0-27.5 1 25 3 5 7 3 1 31.0-31.5 20 1 3 4 4 1 35.0-35.5 21 2 4 5 1 37.5-38.0 2 14 4 10 4 1 2 4 2

211

B.16: Lake INV09-I20 – Raw Diatom Counts (cont’d)

. binodis . Interval (cm) Stauroneis smithii var construens Staurosira venter Staurosira pinnata Staurosirella var (strain IV)Tabellaria flocculosa Tabellaria quadriseptata scales cysts phytoliths plates spicules 0-0.25 18 134 5 11 0 0 0 0.5-0.75 23 113 2 12 0 0 0 1.0-1.25 14 120 4 14 0 0 0 2.0-2.25 18 151 1 13 0 0 0 3.0-3.25 2 23 211 2 4 2 33 0 0 0 4.0-4.25 1 21 189 7 17 0 0 0 5.0-5.25 1 15 249 1 20 0 0 0 6.0-6.25 18 230 0 13 0 0 0 7.0-7.25 22 245 0 22 0 0 0 8.0-8.25 25 212 0 14 0 0 0 9.0-9.25 32 229 2 0 10 0 0 0 11.0-11.25 25 230 0 10 0 0 0 13.0-13.25 12 312 0 7 0 0 0 15.0-15.5 29 251 0 7 0 0 0 17.0-17.5 1 29 265 0 4 0 0 0 19.0-19.5 5 259 1 0 9 0 0 0 23.0-23.5 1 9 244 0 7 0 0 0 27.0-27.5 10 245 0 9 0 0 0 31.0-31.5 1 35 252 0 11 0 0 0 35.0-35.5 11 234 0 9 0 0 0 37.5-38.0 1 8 270 0 8 0 0 0

212

B.17: Lake INV09-C23 – Raw Diatom Counts

. euglypta . . lemanica. var var Interval (cm) acares Achnanthes curtissima Achnanthes exigua Achnanthes ventralis Achnanthes minutissimum Achnanthidium inariensis Amphora libyca Amphora pediculus Amphora Asterionella formosa Caloneis bacillum Cavinula cocconeiformis Cavinula pseudoscutiformis Cocconeis placentula tholiformis Cyclostephanos Cyclotella bodanica Cyclotella michiganiana Cyclotella michiganiana Cyclotella ocellata Cymbopleura amphicephala Denticula keutzingii 0.0-0.25 2 7 1 5 20 2 10 2 3 12 9 6 1 5 0.5-0.75 7 6 2 19 7 6 1 2 1 8 4 3 4 1.0-1.25 3 9 11 1 2 4 7 12 2 2 5 2 2.0-2.25 8 4 12 10 2 16 3.0-3.25 6 12 3 6 21 15 3 3 4.0-4.25 6 4 2 12 4 4 14 2 5.0-5.25 16 4 14 2 14 6.0-6.25 4 16 6 2 8 6 6 4 7.0-7.25 4 8 8 2 8.0-8.25 18 6 6 9.0-9.25 12 6 3 3 10.0-10.25 6 9 6 12.0-12.25 3 3 14.0-14.25 3 3

. meniscus. var

"large" "small" Fragilariforma neoproducta neoproducta Fragilariforma Gomphonema acuminatum Gomphonema parvulum Gyrosigma acuminatum Navicula cryptocephala Navicula peregrina Navicula radiosa Navicula submuralis Navicula vitiosa Interval (cm) Diatoma tenue Diploneis elliptica Diploneis oculata Diploneis parma Diploneis Discostella pseudostelligera herbridicum Encyonema capucina Fragilaria tenera Fragilaria Fragilaria 0.0-0.25 2 1 2 23 1 13 12 3 1 11 4 0.5-0.75 6 30 21 4 1 1 2 3 7 1.0-1.25 3 29 18 5 2.0-2.25 32 14 16 2 6 3.0-3.25 3 36 24 6 9 3 12 4.0-4.25 4 2 12 14 4 2 10 5.0-5.25 6 22 2 12 6 6.0-6.25 3 14 12 4 4 4 7.0-7.25 2 2 10 4 8.0-8.25 3 6 3 12 15 9.0-9.25 6 6 9 6 10.0-10.25 6 6 12.0-12.25 3 9 14.0-14.25 3 9 6

213

B.17: Lake INV09-C23 – Raw Diatom Counts (cont’d)

. binodis .

large" Nupela impexiformis Nupela impexiformis borealis Pinnularia major Pinnularia lanceolatum Planothidium brevistriata Pseudostaurosira parasitica Pseudostaurosira gibba Rhopalodia Rossithidium pusillum disjuncta Sellaphora pupula Sellaphora seminulum Sellaphora anceps Stauroneis construens Staurosira var construens Staurosira Interval (cm) Nitzschia acicularis Nitzschia gracilis Nitzschia palea Nitzschia perminuta Nitzschia " 0.0-0.25 1 5 2 1 7 19 8 5 20 0.5-0.75 7 3 5 28 1 9 13 16 6 1.0-1.25 8 2 8 18 1 2 4 6 8 3 14 2.0-2.25 4 4 18 2 13 3.0-3.25 3 3 18 6 4.0-4.25 6 6 8 26 4 2 14 12 5.0-5.25 6 12 6 4 6 6.0-6.25 2 6 10 2 2 10 7.0-7.25 6 6 10 8.0-8.25 3 15 9.0-9.25 21 6 10.0-10.25 9 27 12.0-12.25 3 6 12 14.0-14.25 3 15

sp1 Interval (cm) venter Staurosira pinnata Staurosirella leptostauron Staurosirella Stephanodiscus scales cysts phytoliths plates spicules 0.0-0.25 16 79 3 49 0 0 0 0.5-0.75 93 3 3 4 86 0 0 0 1.0-1.25 16 97 2 6 69 0 0 0 2.0-2.25 10 102 4 46 0 0 0 3.0-3.25 162 3 48 0 0 0 4.0-4.25 118 0 22 0 0 0 5.0-5.25 170 2 26 0 0 0 6.0-6.25 180 0 18 0 0 0 7.0-7.25 10 228 0 20 0 0 0 8.0-8.25 9 204 0 15 0 0 0 9.0-9.25 9 213 0 30 0 0 0 10.0-10.25 9 225 0 6 0 0 0 12.0-12.25 3 264 0 9 0 0 0 14.0-14.25 9 255 0 9 0 0 0

214

B.18: Lake INV09-C1A – Raw Diatom Counts . euglypta . . lemanica. var var Achnanthes acares acares Achnanthes curtissima Achnanthes exigua Achnanthes marginulata Achnanthes ventralis Achnanthes minutissimum Achnanthidium inariensis Amphora libyca Amphora Asterionella formosa Cavinula cocconeiformis Cavinula pseudoscutiformis Cocconeis placentula Cymbella naviculiformis Cymbopleura amphicephala Cyclotella bodanica Depth Diploneis elliptica Diploneis oculata Diploneis parma Discostella stelligera 0.0-0.5 1 1 1 4 5 12 3 2 2 7 12 3 1 3 1.0-1.5 2 6 2 12 2 2 1 1 2 9 4 5 2.0-2.5 1 5 5 1 7 11 1 9 2 3.0-3.5 3 1 9 3 28 6 4.0-4.5 3 3 4 3 5.0-5.5 6 18 3 3 3 6.0-6.5 6 12 7.0-7.5 3 6 3 6 6 8.0-8.5 18 3 6 3 3 9 9.0-9.5 9 6 3 12 12

" thin

Depth minutum Encyonema Epithemia turgida naeglii Eunotia capucina Fragilaria tenera Fragilaria ulna Fragilaria neoproducta Fragilariforma Frustulia rhomboides Gomphonema angustatum Gomphonema parvulum Gomphonema " Gyrosigma acuminatum Navicula cryptocephala Navicula radiosa Navicula utermoehlii Navicula vitiosa Nitzschia acicularis Nitzschia gracilis Nitzschia palea 0.0-0.5 1 14 1 8 1 1 5 1 2 4 1 7 2 5 1.0-1.5 1 7 1 5 1 2 1 1 1 3 2 1 2.0-2.5 2 2 1 9 2 3 1 3.0-3.5 1 5 7 2 6 1 4 7 4.0-4.5 2 2 2 4 7 1 3 5.0-5.5 6 12 3 3 33 6 6.0-6.5 3 21 6 6 36 3 3 6 7.0-7.5 6 9 3 42 3 8.0-8.5 9 33 6 9 9.0-9.5 3 6 39 6 3

215

B.18: Lake INV09-C1A – Raw Diatom Counts (cont’d)

Depth Nitzschia perminuta Nupela impexiformis major Pinnularia mesolepta Pinnularia microstauron Pinnularia silvatica Pinnularia lanceolatum Planothidium subatomoides Psammothidium brevistriata Pseudostaurosira parasitica Pseudostaurosira Rossithidium pusillum disjuncta Sellaphora laevissima Sellaphora pupula Sellaphora seminulum Sellaphora anceps Stauroneis phoenicenteron Stauroneis Stauroneis smithii construens Staurosira 0.0-0.5 9 10 1 1 1 28 7 38 7 4 1 2 1 1.0-1.5 2 5 19 2 19 7 3 3 1 2.0-2.5 1 8 23 3 6 1 3.0-3.5 1 1 2 4 29 7 1 4.0-4.5 2 1 2 27 2 5.0-5.5 3 39 3 6.0-6.5 3 36 3 7.0-7.5 3 15 3 8.0-8.5 3 3 9 39 3 3 6 9.0-9.5 3 3 45 3 3 3

Depth venter Staurosira pinnata Staurosirella Surirella amphioxys Surirella linearis scales cysts phytoliths plates spicules 0.0-0.5 32 94 8 1 7 98 1 1.0-1.5 57 101 7 7 6 52 2.0-2.5 38 140 10 11 64 1 1 3.0-3.5 33 158 7 5 111 4.0-4.5 22 146 11 8 39 1 1 5.0-5.5 164 3 54 6.0-6.5 147 24 3 66 3 7.0-7.5 180 12 9 3 8.0-8.5 6 138 21 6 101 3 9.0-9.5 171 6 6 63 9

216

B.19: Lake DZO-29-L1 – Raw Diatom Counts

Interval (cm) acares Achnanthes curtissima Achnanthes exigua Achnanthes lanceolota Achnanthes levanderi Achnanthes minutissima Achnanthes pusilla Achnanthes inariensis Amphora libyca Amphora ovalis Amphora pediculus Amphora Asterionella formosa Caloneis bacillum Cyclotella michiganiana Cyclotella pseudostelligera Cymbopleura amphicephala Diatoma tenuis Diploneis oculata Diploneis parma 0.25 2 3 12 1 0.75 2 10 1 1.25 3 1 4 1 2 1.75 1 7 4 1 2.25 10 2 1 2.75 2 4 9 3.25 6 11 1 3 3.75 1 3 14 6 4.25 21 2 1 1 4.75 3 5 1 5.25 2 6 4 5.75 13 6 6.25 1 14 2 1 6.75 3 1 7 1 4 7.25 1 2 5 8 1 7.75 1 2 5 8.25 2 2 7 8.75 2 7 4 9.25 2 1 6 6 9.75 5 15 2 10.25 8 10.75 12 3 11.25 3 7 11.75 2 10 2 1 12.25 2 6 3 12.75 3 7 13.25 2 2 1 1 13.75 3 3 2 3 14.25 3 3 2 14.75 3 1 6 15.25 4 4 5 15.75 6 2 16.25 3 2 16.75 3 2 2 17.25 2 3 5 17.75 6 2 18.25 3 6 18.75 3 2 1 19.25 7 6 19.75 7 1 2 20.25 1 2 1 1 20.75 2 2 21.25 1 2 21.75 2 6 22.25 2 2 7 22.75 2 1 3 23.25 2 4 6

217