Paleolimnological Records of Post-Glacial Lake and Wetland Evolution from the Isthmus of Chignecto Region, Eastern Canada

Hilary White

Thesis Submitted in partial fulfillment of the requirements for the Degree of Master of Science (Geology)

Acadia University Fall Graduation 2012

This thesis by Hilary White was defended successfully in an oral examination on June 27th, 2012.

The examining committee for the thesis was:

______Dr. Darren Kruisselbrink, Chair

______Dr. Linda Campbell, External Reader

______Dr. David Risk, Internal Reader

______Dr. Nelson O'Driscoll, Co-Supervisor

______Dr. Ian Spooner, Supervisor

______Dr. Robert Raeside, Head

This thesis is accepted in its present form by the Division of Research and Graduate Studies as satisfying the thesis requirements for the degree Master of Science (Geology).

………………………………………….

I, Hilary White, grant permission to the University Librarian at Acadia University to reproduce, loan or distribute copies of my thesis in microform, paper, or electronic formats on a non-profit basis. I, however, retain the copyright in my thesis.

______Author

______Dr. Ian Spooner, Supervisor

______Dr. Nelson O’Driscoll, Co-supervisor

______Date

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Table of Contents:

Table of Contents...... iv List of Figures...... vi List of Tables...... vii Acknowledgements...... viii Abstract...... ix

Chapter 1: Introduction...... 1 1.1 Purpose...... 1 1.2 Site Description...... 2 1.3 Geology...... 7 a.) General Geology...... 7 b.) Soils...... 8 c.) Regional Glacial History...... 9 d.) Sea Level History...... 13 1.4 Ecology...... 15 a.) Post-Glacial Colonization...... 15 b.) Modern Ecology...... 16 1.5 Post-Contact Anthropogenic and Environmental Change...... 18 1.6 Regional Research...... 20 a.) Evolution of the Border Marsh Region...... 20 b.) Metals in the Border Marsh Region...... 25 Chapter 2: Methodology...... 29 2.1 Introduction...... 29 2.2 Modern Lake Characterization...... 29 a.) Water Quality...... 29 b.) Lake Bathymetry and Sonar Profiling...... 31 2.3 Lake Sediment Collection and Analysis...... 31 a.) Percussion Coring...... 31 b.) Core Preparation and Stratigraphy ...... 32 c.) Macrofossil 14C Dating...... 32 d.) Loss on Ignition...... 33 e.) Magnetic Susceptibility...... 33 f.) Carbon and Nitrogen Analysis...... 34 g.) Elemental Analysis...... 36 h.) Paleosalinity...... 37 i.) Mercury Analysis...... 37 Chapter 3: Results and Interpretation...... 40 3.1 Regional Water Quality...... 40 3.2 Carbon Dating...... 41 3.3 Proxy Analysis...... 42 A. Jolicure Lake...... 42 I. Results...... 42 a.) Modern Lake Characterization...... 42 i.) Field Observations...... 42

ii.) Water Quality...... 42 iii.) Basin Morphometry and Sediment Distribution...... 43 b.) Stratigraphy and Age of Sediment...... 43 i.) Lake Sediment Cores...... 43 ii.) Dating...... 45 iii.) Lithostratigraphic Units...... 45 c.) Chemostratigraphic Results...... 48 i.) Carbon/Nitrogen Ratio...... 48 ii.) Paleosalinity...... 48 iii.) Lead and Mercury Concentrations...... 49 II. Interpretation………………………………………………………………….50 B. Long Lake...... 53 I. Results...... 53 a.) Modern Lake Characterization...... 53 i.) Field Observations...... 53 ii.) Water Quality...... 53 iii.) Basin Morphometry and Sediment Distribution...... 54 b.) Stratigraphy and Age of Sediment...... 56 i.) Lake Sediment Cores...... 56 ii.) Dating...... 56 iii.) Lithostratigraphic Units...... 57 c.) Chemostratigraphic Results...... 57 i.) Carbon/Nitrogen Ratio...... 57 ii.) Paleosalinity...... 57 iii.) Lead and Mercury Concentrations...... 60 II. Interpretation………………………………………………………………….61 C. Blair Lake……….…………………………………………………………….64 I. Results…………………………………………………………………………64 a.) Modern Lake Characterization...... 64 i.) Field Observations...... 64 ii.) Water Quality...... 64 iii.) Basin Morphometry and Sediment Distribution...... 65 b.) Stratigraphy and Age of Sediment...... 65 i.) Lake Sediment Cores...... 65 ii.) Dating...... 67 iii.) Lithostratigraphic Units...... 67 c.) Chemostratigraphic Results...... 69 i.) Paleosalinity...... 69 ii.) Lead and Mercury Concentration...... 69 II. Interpretation…………………………………………………………………71 Chapter 4: Discussion and Conclusions………...... 73 4.1 Introduction...... 73 4.2 Age and Evolution of the Border Marshes...... 73 a.) 14,000-8,000 cal. yr. B.P...... 73 b.) 8,000-4,500 cal. yr. B.P...... 77 i. Landscape evolution...... 77

ii. Salt water ingress...... 81 c.) 4,500-present...... 82 4.3 Metals in the Environment...... 89 4.4 Management Implications and Conclusions...... 95 Chapter 5: References...... 99 Appendices...... 115 Appendix 1: Jolicure Lake Raw Data………...... 115 Appendix 2: Long Lake Raw Data...... 121 Appendix 3: Blair Lake Raw Data...... 126

List of Figures:

No. Description Page

1.1 Location map for study area 3 1.2 Atlantic migratory flyway 4 1.3 Location of Jolicure Lake 5 1.4 Location of Long Lake 6 1.5 Location of Blair Lake 6 1.6 Bedrock geology of the region 8 1.7 Glacial history of the region 10 1.8 Sea level and tidal range 13 1.9 Sea level and marsh aggradation 15 1.10 Ganong’s (1903) model of marsh evolution 23 2.1 C/N vs. δ13C biplot 39 3.1 Jolicure Lake bathymetry and sonar transect 44 3.2 Jolicure Lake lithostratigraphic units 46 3.3 Jolicure Lake multi-proxy results 47 3.4 Jolicure Lake C/N vs. δ13C biplot 49 3.5 Long Lake bathymetry and sonar transects 55 3.6 Long lake lithostratigraphic units 58 3.7 Long Lake multi-proxy results 59 3.8 Long Lake C/N vs. δ13C biplot 60 3.9 Blair Lake bathymetry and sonar transects 66 3.10 Blair Lake lithostratigraphic units 68 3.11 Blair Lake multi-proxy results 70 4.1 Landscape evolution 74 4.2 Conceptual model of region at ~11,000 cal. yr. B.P. 76 4.3 Mean tide from deglaciation to ~300 cal. yr. B.P. 78 4.4 Conceptual model of region at ~7,000 cal. yr. B.P. 80 4.5 Conceptual model of region at ~4,000 cal. yr. B.P. 83 4.6 Conceptual model of region at ~300 cal. yr. B.P. 87 4.7 Conceptual model of modern day region 88 4.8 Linear regression of magnetic susceptibility and lead 90 4.9 Linear regression of loss on ignition and mercury 91 4.10 Linear regression of mercury and chloride 93

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List of Tables:

No. Description Page

2.1 Summary of proxies used in this study 30 3.1 Averages water quality parameters for all three study lakes 40 3.2 Compiled radiocarbon data for all three study lakes 41 3.3 Average water quality parameters for Jolicure Lake 43 3.4 Jolicure Lake radiocarbon dates 45 3.5 Average water quality parameters for Long Lake 54 3.6 Long Lake radiocarbon dates 56 3.7 Average water quality parameters for Blair Lake 65 3.8 Blair Lake radiocarbon dates 67

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Acknowledgements:

This research was funded by NSERC, Ducks Unlimited Canada, Acadia

University, Irving Oil, Dr. Timothy Jull at the University of Arizona’s NSF-AMS facility, the Geological Society of America, and Dr. David Risk and the CREATE program. I would like to thank first and foremost Dr. Ian Spooner for his mentoring and constant support as he not only pushed me to become a better scientist, but to become a better person as well. I would also like to thank Dr. Nelson O’Driscoll for his guidance and advice. A special thanks to Dewey Dunnington for all of his help in the field. I would also like to thank Dr. Chris White for providing the means to carry out XRF analysis and all of the Acadia University Department of Earth and Environmental Science professors and students for their support and encouragement. Finally, I would like to thank my family for their unfailing love and encouragement and for always believing in me.

Abstract:

The Isthmus of Chignecto on the New Brunswick - Nova Scotia border is the location of the Tantramar, Missaguash, and Amherst Marshes, which together form a large coastal wetland system that has been the focus of much ecosystem research and habitat modification even though little is known about the systems’ evolution. In this study, lithostratigraphic and chemostratigraphic lake sediment records from three lakes are used to provide a high resolution record of post-glacial environmental change for the region.

Basal dates for the study lakes range from >10,000 cal. yr BP to < 4000 cal. yr

BP, indicating that each lake provides a unique story on landscape and salt marsh evolution. Lake sediment stratigraphy indicates rapid fluctuations in lake productivity.

Chemostratigraphic proxies indicate fluctuating salinity and oxygen levels in two of the three lakes and show that multiple saltwater incursions likely occurred. Analyses of metals indicate anomalously high pre-historic concentrations of Pb and Hg (8 ppm and

870 ppb respectively). Historic concentrations of Pb and Hg provide evidence for significant atmospheric deposition from industrialization and anthropogenic sources.

Collectively, these data suggest that a sophisticated model is required to adequately explain the physical evolution of this extensive wetland system. Periods of sustained saltwater influx into freshwater systems were likely a fundamental driver of systems change. Additionally, both anthropogenic and natural disturbances of the lakes and wetlands have the potential to increase the bioavailability of contaminants.

Management of these wetlands must take into account the sensitivity of the wetland system to environmental disturbance.

Chapter 1: Introduction

1.1 Purpose

The Isthmus of Chignecto, Nova Scotia-New Brunswick, is the location of a large coastal wetland system referred to in this thesis as the Nova Scotia-New Brunswick

Border Marshes. This site is managed by a wide variety of stakeholders including Ducks

Unlimited Canada, Canadian Wildlife Services, and Parks Canada. Habitat modification is pervasive and the site has been the focus of much ecosystems research; however, the physical evolution and dynamics of these wetlands and surrounding environments are poorly understood (Chalmers, 1895; Ganong, 1903; Walker, 1980; Howell and Kerekes,

1982; Walker et al., 1985; Scheffer et al., 2001; Taylor, 2005; MacKinnon, per. com.

2011).

This research focuses on using lithostratigraphic and chemostratigraphic lake sediment records from three lakes (Jolicure Lake, Long Lake, and Blair Lake) to provide a continuous, high resolution record of post-glacial environmental change. The results of this study will provide insight into 1) the timing of the establishment of the wetland system, 2) the timing of major lacustrine and wetland environmental shifts, 3) the influence of large scale systems (i.e. climate, storm patterns) on physical and chemical wetland dynamics, 4) the relative influence of aquatic versus terrestrial carbon sources on lake trophic status through time, 5) the relative influence of freshwater and saltwater on system evolution, 6) baseline pre- and post-contact metal concentrations, and 7) the relationship between metal concentrations and lake and wetland systems dynamics. This research will lead to an understanding of system sensitivity to environmental change, the development of a model of natural system evolution, and an understanding on the impact

1 of anthropogenic activity; all of which are essential to the effective management of coastal wetland systems (Perillo et al., 2009).

1.2 Site Description

The three study lakes (Jolicure Lake, Long Lake, and Blair Lake) are located within an extensive network of largely uninhabited freshwater lakes and wetlands along the Bay of Fundy coast on the Isthmus of Chignecto (Davis and Browne, 1996;

Macdonald and Clowater, 2007; Figure 1.1). The Isthmus of Chignecto is narrow, 21km in length, and connects the peninsular province of Nova Scotia to New Brunswick and mainland Canada. The Isthmus of Chignecto also separates the cold, macrotidal waters of the Chignecto Bay to the south and the Northumberland Strait to the north (Macdonald and Clowater, 2007). The glacial and sea level history of the region is complex and has strongly influenced the current physical state of the Border Marshes (Roland, 1982; Stea et al., 2001; Macdonald and Clowater, 2007).

The study area is referred to as the Nova Scotia-New Brunswick Border Marshes

(abbreviated herein to the Border Marshes), and consists of three major marsh/wetland systems, including the Tantramar Marsh, the Missaguash Marsh, and the Amherst Marsh, which are jointly managed by provincial and national authorities in conjunction with

Ducks Unlimited Canada (Davis and Browne, 1996; Macdonald and Clowater, 2007).

The Border Marshes contain five major rivers that drain into the Chignecto Bay, which are the Tantramar River, the Aulac River, the Missaguash River, the Laplanche River, and the Nappan River (Macdonald and Clowater, 2007).The three main marshes are separated by northeast-southwest trending structural ridges at the coast but merge somewhat further inland (Gussow, 1953; Roland, 1982; Macdonald and Clowater, 2007;

Figure 1.1).

Figure 1.1 Location map for study area. A. Overview of study area location. B. Location of the Nova Scotia-New Brunswick Border Marshes and the three study lakes. The orange dashed lines represent the NE-SW structural ridges that separate the three major marshes (Google Earth image, 2011).

The Border Marshes are a site of national, historical, and cultural significance. In

1755, the French and British fought the Battle of Fort Beauséjour; this battle was the beginning of British offensive action in the Seven Years War (1756-1763; Wynn, 1979).

The British victory in this battle and the surrender of other French garrisons in the region led to the removal of French military presence. Due to this, the British initiated the expulsion of the Acadians from Maritime Canada (Wynn, 1979).

Additionally, the Border Marshes are an important resting site for migratory waterfowl since the Isthmus of Chignecto is located along part of the major Atlantic migratory flyway (Continental Technical Team, 2003; Figure 1.2). The name Tantramar is derived from the Acadian French "tintamarre", meaning 'din' or 'racket' in reference to the noisy flocks of birds which feed and migrate through this area (Continental Technical

Team, 2003; Bunker-Popma, 2006; Macdonald and Clowater, 2007; Fisheries and Oceans

Canada, 2010).

Figure 1.2 The study area (black star) is located along part of the Atlantic migratory flyway (black arrow; Boere and Stroud, 2006; Milton et al., 2006).

The three study lakes are shallow and are located at varying distances from the

Bay of Fundy coastline (Figure 1.1). Jolicure Lake is the deepest lake within a system of three lakes in the Tintamarre National Wildlife Area within the Tantramar Marsh (77 ha,

2 m maximum depth; Figure 1.3). Many of the lakes found on the Isthmus of Chignecto are similar to Jolicure Lake and have been categorized as shallow with an almost neutral pH (range of 6.50-8.20), close to the transition between a lake that can support fish and other large aquatic organisms, and a wetland (Walker and Paterson, 1986; Austin-Smith

Jr. and Bowes, 2000). Studies have suggested that many of these lakes were likely formed from blocked river drainage as a result of salt marsh aggradation (Ganong, 1903; Walker and Paterson, 1986). Long Lake is also a small, shallow lake that is drained by the

LaPlanche River, through the Amherst Marsh (93 ha, 1.9 maximum depth; Figure 1.4).

Figure 1.3 Location of Jolicure Lake. White dashed line represents approximate border between the freshwater marshes and wetlands of the Tintamarre National Wildlife Area and the cultivated and forested inland (Google Earth image, 2011).

Figure 1.4 Location of Long Lake. White dashed line represents approximate border between the freshwater marshes and wetlands and the forested inland (Google Earth image, 2011).

Figure 1.5 Location of Blair Lake. White dashed line represents approximate border between the freshwater marshes and wetlands and the forested inland (Google Earth image, 2011).

Long Lake is bounded by wetland on the coastal side and the inland portion is bounded by sandy, glacial outwash sediment (Dunnington, 2011). Blair Lake is the closest study lake to the Bay of Fundy coast and borders the southern portion of the Amherst Marsh

(110 ha, 4.6 m maximum depth; Figure 1.5). This lake is the deepest of the three study lakes and is unique in that it is located near both residential and commercial development

(Taylor, 2005).

1.3 Geology

A.) General Geology

In the study area there is a thick cover of glacial till and/or glacial outwash sediment beneath the modern wetland/marsh soils (see Section 1.3b). These glacial deposits are underlain by the late Carboniferous Pictou and Cumberland groups sedimentary rocks, the early to late Carboniferous Mabou Group, and the early

Carboniferous Windsor Group chemical sedimentary rocks (Gussow, 1953; Rampton and

Paradis, 1981; Ryan and Boehner, 1994; Keppie, 2000; Johnson, 2008; Figure 1.6).

Jolicure Lake lies within the Richibucto Formation of the Pictou Group, which includes grey and brownish red, fine grained sandstone, pebbly sandstone and conglomerate, and brownish red to brick red and grey siltstone and mudstone (Gussow, 1953; Rampton and

Paradis, 1981; Johnson, 2008). Long Lake lies within the Balfron Formation of the Pictou

Group, which includes fluvial sandstone, conglomerate, floodplain mudstone, mudstone, and rare lacustrine limestone (Keppie, 2000). Blair Lake lies within two different

Carboniferous groups, the Middleborough and Shepody formations of the Mabou Group, which includes floodplain mudstone, fluvial sandstone, and rare conglomerate and limestone, and the middle Windsor Group, which includes halite, anhydrite, gypsum, and mudstone (Keppie, 2000).

Bedrock in this region is gently folded and contains several gently dipping synclines and anticlines trending northeast-southwest, best represented by Aulac Ridge which divides the Tantramar and Missaguash marshes and extends to Baie Verte (Ells,

1887; Gussow, 1953; Johnson, 2008; Figure 1.1 and 1.6).

Figure 1.6 Bedrock geology of the region (Keppie, 2000; Johnson, 2008).

B.) Soils

There are three main soil types within in the study region; 1) Acadia soils, 2) marshland peat bogs, and 3) Masstown soils (Davis and Browne, 1996; Austin-Smith Jr. and Bowes, 2000). The Acadia soils are found on the reclaimed dyke land at the coast, and extend several miles inland (Davis and Browne, 1996). These soils are imperfectly drained, red-brown or grey, silty clay loams indicative of gleying (Davis and Browne,

1996). They also have little horizon development due to continuous marine sediment deposition; however, when the Acadia soils are drained and reclaimed they become fertile and valuable for agricultural use (Davis and Browne, 1996; Austin-Smith Jr. and Bowes,

2000).

The marshland peat bogs contain poorly drained, highly organic soils that are formed on mostly flat, low-lying, marsh terrain, inland from the Acadia soils (Davis and

Browne, 1996; Austin-Smith Jr. and Bowes, 2000). This soil horizon is usually no more than one metre thick and contains remnants of drowned forests within peat layers (Davis and Browne, 1996; Austin-Smith Jr. and Bowes, 2000). The adjacent Masstown mineral soils also form on low lying areas and are poorly drained due to the depressions in the land and hummocky nature of the terrain (Davis and Browne, 1996; Austin-Smith Jr. and

Bowes, 2000). The surface layer is ≤ 15 cm of organic matter, which is underlain by a

~25 cm thick sandy "A" horizon (Davis and Browne, 1996).

C.) Regional Glacial History

The glacial history of Atlantic Canada is complex and several events are juxtaposed on the landscape, often making interpretation of sediments difficult. The dominant ice flow events of the Wisconsinan glaciation period (focusing on the last

75,000 yrs) have been interpreted from glacial deposits and striation data (Stea et al.,

1992a; Stea et al., 1992b; Stea et al., 1998; Davis and Browne, 1996). Ice flow events have been separated into distinct phases by Stea et al. (1987, 1992a, 1992b, and 1996) and Stea and Mott (1989) and have all been summarized in Stea et al. (1998; Figure 1.7).

Phase 1 (Caledonia Phase; Figure 1.7) occurred from the early to mid-

Wisconsinan (~75,000 - 40,000 cal. yr. B.P.; Stea et al., 1998). The ice flow was to the

1 Legend White - ice Stipple - ocean Cross-hatch - emergent land areas Solid lines - possible ice shelf Dashed arrows - flow lines Dotted arrows - later flow line, same phase E - Escuminac ice centre G - Gaspereau ice centre C - Chignecto glacier A - Antigonish Highlands ice centre SM - South Mountain ice centre H - Cape Breton Highlands ice centre Caledonia Phase C - Prince Edward Island ice centre ca. 75 - 40ka a - Study area

2 3

Scotian Phase Escuminac Phase ca. 18 - 15ka ca. 22 - 18ka

4 5

Chignecto Phase Collins Pond Phase ca. 13 - 12.5ka ca. 10.8ka

Figure 1.7 Proposed Wisconsinan ice flow. Bold numbers in the upper right hand corners indicate the ice flow phase (modified from Stea et al., 1998).

10 east across the entirety of Maritime region and the terminus of the ice sheet extended to the Scotian Shelf, creating an end moraine complex (Stea et al., 1996; Stea et al., 1998).

The majority of drumlin fields in Nova Scotia were formed during this ice flow phase

(Stea and Mott, 1989; Davis and Browne, 1996). At this time, the Isthmus of Chignecto was completely covered in ice. Phase 2 (Escuminac Phase; Figure 1.7) occurred during the late Wisconsinan (~22,000 - 18,000 cal. yr. B.P.; Stea et al., 1998). The dominant ice flow direction was southward away from the Escuminac Ice Center in the Prince Edward

Island region. This ice flow phase produced the north-south and northwest-southeast alignment of mainland Nova Scotia geomorphological features (Stea and Mott, 1989;

Davis and Browne, 1996). The study area remained ice covered during this phase of

Wisconsinan glaciation.

During Phase 3 (Scotian Phase; late Wisconsinan; ~18,000 - 15,000 cal. yr. B.P.;

Stea et al., 1998; Figure 1.7), the Scotian Ice Divide developed coincident with a northward flow across the northern mainland of Nova Scotia and into New Brunswick and a southward flow terminating at the Scotian Shelf End Moraine Complex (Stea and

Mott, 1989; King, 1996; Stea et al., 1998). By 16,700 cal. yr. B.P. the ice cover over the entirety of Nova Scotia began to diminish and ice receded out of marine areas, leaving the Bay of Fundy deglaciated (Grant, 1980; Stea and Mott, 1998). During this time, the

Scotian ice sheet is thought to have transformed into several smaller, distinct ice sheets throughout the Maritimes (i.e. South Mountain Ice Cap, Chignecto Glacier, and

Chedabucto Bay Glacier; MacNeill and Purdy, 1951; Stea et al., 1998; Davis and

Browne, 1996). The study area would likely have been ice free during this time.

However, there is a proposed glacial re-advance during the late Wisconsinan (13,000-

12,500 cal. yr. B.P.), known as Phase 4, the Chignecto Phase (Stea et al., 1998; Figure

1.7). This ice flow phase kept most of the Maritimes ice covered and correlates with glacial re-advances in Newfoundland and New Brunswick (Borns and Hughes, 1977;

Brookes, 1977). During this period, the glacial re-advance likely led to the study area becoming ice-covered again.

Climate became warmer and drier leading to the dissipation of glaciers and the colonization of shrubs, herbaceous plants, and trees in ice-free areas by 13,900 cal. yr.

B.P. (Mott and Stea, 1994; Davis and Browne, 1996; Miller, 1995). During this warming period (Allerød), there was the establishment and migration of vegetation, which led to the stabilization of slopes and shorelines, decreased minerogenic input into lakes, and increased productivity and sedimentation rates (Stea and Mott, 1998). At the Allerød-

Younger Dryas transition, climatic cooling has been suggested to have caused ice re- advance by reactivating remnant ice or forming new ice caps in some locations in the

Maritimes (Stea and Mott, 1989; Stea and Mott, 1998; Stea et al., 1998). This period has been referred to as Phase 5, or the Collins Pond Phase, and occurred during the Younger

Dryas cooling event (~10,800 cal. yr. B.P.; Mott and Stea, 1994; Stea et al., 1998; Figure

1.7). It was at this time that the study area became ice free. Lake sediments from this period contain low organic carbon content and increased mineral sediment deposition due to persistent ice and snow cover that decreases plant cover and increases watershed erosion (King, 1994; Mott, 1994; Stea and Mott, 1998). From 12,500 - 10,000 cal. yr.

B.P., there were periods of glacial retreat and advance that were followed by an overall regional retreat at which point Nova Scotia and the Maritimes became mostly ice free

(Stea et al., 1998; Fader, 2005).

Currently, the Maritimes and the Isthmus of Chignecto are experiencing tectonic subsidence due to the collapse and migration of a forebulge that had previously existed along the boundaries of the North American ice sheets (Daigle, 2006). Subsidence is also occurring as a result of water loading of the seabed in the Bay of Fundy and the Gulf of

St. Lawrence in response to post-glacial global sea level rise of more than 100 m (Daigle,

2006).

D.) Sea Level History

During the Quaternary, sea level varied cyclically by as much as 120 metres; however, the relative sea level (RSL) rose throughout eastern Canada (Amos and Zaitlin,

1985; Scott et al., 1987; Shaw and Forbes, 1990; Davis and Browne, 1996; Fader, 2005;

Figure 1.8). The sea level history in the Isthmus of Chignecto region is characterized by

Figure 1.8 Sea level and tidal range in the inner Bay of Fundy based on data from the Chignecto Bay (modified from Amos and Zaitlin, 1985).

13 rapid changes with mean sea level being 55 m above present sea level at ~15,000 cal. yr.

B.P. and 25 m below present sea level at ~7,000 cal. yr. B.P (Scott and Greenburg, 1983;

Amos et al., 1991; Fader, 2005). There were also significant changes in tidal range over the past ~15,000 cal. yr. B.P., varying from less than 2 m to more than 12 m (see Figure

1.8). Currently, average relative sea level rise in Nova Scotia is between 25 and 30 cm/century, which is due to the combination of crustal subsidence and global sea level rise (Shaw and Cemen, 1999).

Studies on sea level change in the Maritimes have found that rapid sea level rise has been occurring in Atlantic Canada over the past 300 to 400 years (Shaw et al., 1998;

Shaw and Ceman, 1999). Through a ~4,000 year record of marsh aggradation, representing the range of higher high water (HHW) using basal 14C ages on bulk sediment and macrofossils from the base of marsh deposits at Amherst Point, Nova

Scotia, along with the approximated influence of crustal subsidence and increase in tidal range, Shaw and Cemen (1999) were able to determine that sea level rise in this region is likely due to natural eustatic fluctuations with a range of ~0.8 m (Figure 1.9). These natural eustatic fluctuations (~0.8 m), in combination with regional crustal subsidence, the increase in tidal range, and changing climate in Maritime Canada, could result in the predicted sea level rise by 2100 of approximately 0.5 m to increase significantly (Shaw et al., 1998; Shaw and Ceman, 1999; Figure 1.9 inset). Also, a projected increase in hurricanes and accelerated coastal erosion will contribute to the increase in potential for saltwater inundation of the freshwater lakes and marshes on the Isthmus of Chignecto

(Sanders et al., 2008; Daigle, 2006).

Eustatic Fluctuations

Figure 1.9 Marsh aggradation is constrained by the faint lines representing the range of higher high water (HHW) increase, the bold line represents the median HHW value. The dotted line approximates the crustal subsidence and increase in tidal range. Subtraction of this approximation from the median HHW produces a graph depicting eustatic fluctuations with a range of ~0.8 m over the past ~3,000 years (inset). Natural eustatic fluctuations superimposed on the previously mentioned factors in Maritime Canada could result in the increase of predicted sea level rise and salt marsh aggradation (modified from Shaw and Cemen, 1999).

1.4 Ecology

A.) Post-Glacial Colonization

Several studies have supported the concept that post-glacial floral and faunal colonization was the result of rapid migration of species into Nova Scotia and the expansion of selected species that resided within refugia (Dahl, 1987; Gugerli and

Holderegger, 2001; Brochmann et al., 2003; Gosse, 2003; Curry, 2007). This concept has been supported by evidence that several species now found in Nova Scotia lack long distance dispersal mechanisms and exist as disjunct populations (Dahl, 1987; Brochmann et al., 2003). These species were able to colonize Nova Scotia by traveling across the then larger isthmus (MacDonald and Clowater, 2007; Fensome and Williams, 2001). Boreal

15 and Maritime Acadian forest vegetation, including birch, spruce, fir, ash, and cedar species began to dominate between 10,000 and the present, with pines, hemlocks and hardwoods added to the floral assemblage more recently (Davis and Browne, 1996;

MacDonald and Clowater, 2007).

B.) Modern Ecology

The ecology on the Isthmus of Chignecto is diverse, and the region contains a variety of biomes, including open saltwater, mud-flats, salt marshes, freshwater wetlands, rivers, lakes, agricultural lands, as well as conifer and deciduous upland forests (Austin-

Smith Jr. and Bowes, 2000). The Bay of Fundy coastal region of the Isthmus of

Chignecto has been identified as one of the most important areas for wildlife conservation and agricultural use in eastern Canada due to soil quality and productive waterfowl habitat (Davis and Browne, 1996; Austin-Smith Jr. and Bowes, 2000).

As mentioned previously, the three major marshes on the Isthmus of Chignecto’s

Bay of Fundy coast are the Tantramar Marsh, Missaguash Marsh, and Amherst Marsh.

Together, they form a mosaic of both natural and manmade wetland habitats (> 2700 ha)

(Davis and Browne, 1996; Austin-Smith Jr. and Bowes, 2000; Continental Technical

Team, 2003). The manmade impoundments were constructed and are managed by the

New Brunswick and Nova Scotia Departments of Environment and the Canadian Wildlife

Service in conjunction with Ducks Unlimited Canada (Maillet et al., 1999; Austin-Smith

Jr. and Bowes, 2000; MacKinnon, per. com., 2011). These impoundments have three to fifty times higher brood densities of resident and migratory waterfowl than the natural wetlands in the area (Davis and Browne, 1996; Austin-Smith Jr. and Bowes, 2000;

Continental Technical Team, 2003). The wetlands and manmade impoundments provide

16 habitat for waterfowl (i.e. Canada Goose, American Black Duck), as well as regionally rare species, including Northern Shoveler (Anas clypeata), Gadwall (Anas strepera), and

Virginia Rail (Rallus limicola; Austin-Smith Jr. and Bowes, 2000; Continental Technical

Team, 2003). Along the edges of the impoundments and wetland ditches and channels, species of alder, willow, and other shrubs provide nesting habitat for a variety of songbirds, including red-winged blackbirds (Agelaius phoeniceus), swamp sparrows

(Melospiza georgiana), and yellow warblers (Dendroica aestiva) (Austin-Smith Jr. and

Bowes, 2000).

This habitat also provides a resting area for shorebirds during migration.

Muskrats, striped skunks, raccoons, white-tailed deer, and otter are the main mammals that reside in the Border Marshes (Austin-Smith Jr. and Bowes, 2000). Birds of prey (e.g. northern harriers and short-eared owls) use the wetlands and impoundments for foraging

(Austin-Smith Jr. and Bowes, 2000). On the edges of the wetlands, larch (Larix laricina) and black spruce (Picea mariana) are present, as well as sphagnum moss, pale laurel

(Kalmia polifolia), bladderworts (Utricularia spp.), and sundews (Drocera spp.), which add to the plant diversity of the area (Austin-Smith Jr. and Bowes, 2000).

There are also several freshwater lakes within the Isthmus of Chignecto’s Bay of

Fundy coastal system (Austin-Smith Jr. and Bowes, 2000; MacDonald and Clowater,

2007). The majority of lakes within this area are close to the transition from a lake that can support fish and other large aquatic organisms to a wetland; many contain large mats of floating bog (Austin-Smith Jr. and Bowes, 2000). These lakes typically contain a variety of aquatic plants including cattails (Typha spp.), arrowheads (Sagittaria spp.), water parsnip (Sium suave), and yellow pond-lily (Nuphar lutea) (Austin-Smith Jr. and

Bowes, 2000; Fisheries and Oceans Canada, 2010). Many of the shallow lakes in this region support populations of shallow, warm water game and prey fish species, including brown bullhead (Ameiurus nebulosus), white and yellow perch (Perca spp.), small numbers of smallmouth bass (Micropterus dolomieu) and several trout species

(Salmoninae spp.) (Austin-Smith Jr. and Bowes, 2000; Fisheries and Oceans Canada,

2010). Other wildlife species, including various aforementioned waterfowl, Osprey

(Pandion haliaetus), kingfishers (Ceryle alcyon), Common Loons (Gavia immer), muskrats (Ondatra zibethicus), and beavers (Castor canadensis), also reside in this habitat (Austin-Smith Jr. and Bowes, 2000).

1.5 Post-Contact Anthropogenic and Environmental Change

The post-glacial evolution of the lake and salt marsh environments in this area has also been affected by both anthropogenic and natural processes. Human activity has had a significant impact on the Border Marshes region. Prior to European settlement in the late

1600’s, Mi’kmaq inhabitants relied on the wetlands for survival (Thurston, 2004;

MacDonald and Clowater, 2007). In the local Mi’kmaq dialect, the word ‘Chignecto’ refers to "the great marsh district" (Thurston, 2004). The natives used the wetlands within the Border Marshes to harvest waterfowl, fish, and potentially porcupine and moose

(MacDonald and Clowater, 2007).

When the Acadians first arrived in Atlantic Canada in the 17th century, their agricultural practices relied on the reclamation of fertile tidal land from the ocean by the creation of extensive dyke systems, which led to mud levees along the rivers and creeks in the area (Wynn, 1979). More than 70% of the area originally covered by salt marshes was converted for hay cultivation and livestock grazing (Erskine and McManus Jr., 2005;

MacDonald and Clowater, 2007). Adjacent, upland forests were cleared to create

18 defendable land, agricultural land, and firewood (MacDonald and Clowater, 2007).

These extensive modifications altered lakes and surface drainage patterns, significantly impacted the distribution and quantity of freshwater habitat, and likely had an impact on waterfowl use patterns (Wynn, 1979; MacDonald and Clowater, 2007). By the 1750s, there were approximately 4,000 Acadians residing on the Isthmus (Smith and Mackinnon,

1995; MacDonald and Clowater, 2007).

When the Acadians were expelled from the Border Marshes region, the reclaimed marshlands were abandoned until the 1760s when the New England settlers utilized a substantial amount of the marshland and logged extensively due to an increase in timber demand for the shipbuilding industry, which resulted in the retreat of the forests inland

(Wynn, 1979; MacDonald and Clowater, 2007). From that period to the present, the region has experienced constant and significant alteration (Marlin et al., 2007). In the

1800s, agriculture on the marsh lands intensified with a large emerging marsh hay economy and extensive new drainage, ditching, and dyking systems were incorporated

(Wynn, 1979). However, in the 1900s, hay harvesting became uneconomical and the role of agriculture on the marsh lands declined. The marshes were then transformed into pastures for livestock (Wynn, 1979; Marlin, 2007).

During the post-war period (post-1945), urban migration from rural areas was increasing and the Maritimes Marshland Rehabilitation Act (MMRA, 1948) was established in order to support regional agricultural industry (Erskine and McManus Jr.,

2005; MacDonald and Clowater, 2007). Dams and sluice gates were installed in the estuaries of the Tantramar River and Missaguash River to improve drainage and eliminate tidal influence on the dykelands (Erskine and McManus Jr., 2005; MacDonald

19 and Clowater, 2007). The MMRA was counteracted after the 1960s when Ducks

Unlimited Canada and Canadian Wildlife Service placed significant attention on the marsh lands as a habitat for waterfowl and wetland wildlife (MacDonald and Clowater,

2007).

Today, the Border Marshes are located within an important transportation corridor and their position with respect to magnetic north led to the installation of several short wave radio transmission towers by CBC Radio throughout the area (Davis and Browne,

1996). The Border Marshes are bounded by the towns of Sackville, New Brunswick and

Amherst, Nova Scotia and the area is now mostly rural residential with small-scale agriculture (MacDonald and Clowater, 2007).

1.6 Regional Research

A.) Evolution of the Border Marsh Region

The evolution of the Isthmus of Chignecto’s wetlands and lakes is poorly understood. As previously discussed, the Isthmus of Chignecto region is experiencing tectonic subsidence due to the forebulge migration and collapse and rapid sea level rise over the past 300 to 400 years as a result of natural eustatic fluctuations with a range of

~0.8 m (Shaw et al., 1998; Shaw and Ceman, 1999; Daigle, 2006). The predictions for global climate change from the Intergovernmental Panel on Climate Change (IPCC) within the 21st century indicate a low to high scenario range of a 2-6° C temperature rise and an 18-59 cm increase in sea level (IPCC, 2007). However, with the subsidence and sea level rise, as well as with the changing climate in Maritime Canada, predicted sea level rise could be substantially greater (Shaw et al., 1998; Shaw and Ceman, 1999). In addition, a projected increase in hurricane recurrence and strength and accelerated coastal

20 erosion will contribute to the increase in potential for saltwater inundation of the freshwater lakes and wetlands in the Border Marshes region (Sanders et al., 2008; Daigle,

2006).

It is becoming increasingly expensive to maintain the dykes and the impact of dyke removal on the physical and chemical condition of these lakes and wetlands is unknown (Daigle, 2006; Marlin et al., 2007). Currently, scientists are researching the effects of dykeland reclamation by a controlled removal of some existing dykes in the area (MacDonald and Clowater, 2007; Marlin et al., 2007). Research by Millard et al.

(2007) utilized LiDAR digital elevation models to predict the effects of dyke removal or relocation on salt marsh vegetation zone limits near Fort Beauséjour, New Brunswick.

The digital elevation models, in combination with previous studies on recovering marshes, serve as analogs for restoration efforts (Crooks et al., 2002; Millard et al., 2007;

Crooks et al., 2011).

Additionally, most of the freshwater lakes within this study region are shallow and thus are extremely susceptible to habitat degradation as a result of short term climate change (Carvalho and Kirika, 2003; Schep et al., 2007). These studies suggest that ocean warming will disrupt regional climate patterns and will alter water quality, the overall functioning, and the general ecological status of shallow lakes (Carvalho and Kirika,

2003; Schep et al., 2007).

A water quality assessment was completed on Blair Lake in 2005, which found that the study lake was highly productive and eutrophic with high nutrient levels and recurring algal blooms (Taylor, 2005). No identification or assessment of the nutrient sources was carried out, but it was suggested that human-related nutrient sources were the

21 reason for eutrophication (Taylor, 2005). Taylor (2005) suggested erosion control measures, good livestock manure management and suitable sewage disposal systems as appropriate measures to reduce nutrient influx. No paleolimnological research was completed to determine whether or not Blair Lake has recently evolved into this highly productive, eutrophic lake or if this condition had developed in pre-historic times.

Several paleolimnological and geomorphological studies have been completed in the region. A paleolimnological study entitled “Post-glacial climate change and its effect on a shallow dimictic lake in Nova Scotia” (Lennox et al., 2010) is an example of how a study of the paleodynamics of a lake can provide information that can be used to both adapt to and mitigate the effects of future environmental change. This study used a series of lake sediment cores to identify how regional climate change impacts lake water and habitat quality. Proxy data preserved in the sedimentary record was used to determine historic and pre-historic past water levels and temperature, as well as the trophic state of the system. In this study, similar methods have been employed. Several other paleoclimate studies were completed on the Isthmus of Chignecto focusing on the deglaciation and climate change prior to and during the Younger Dryas (Mott et al., 1986;

Stea and Mott, 1998; Shaw et al., 1998). The Younger Dryas was a time of abrupt cooling that had a significant effect on the both landscape and the vegetation of Nova Scotia

(Mott et al., 1986). This change is recorded in the sediment record of lakes as an inorganic layer above the organic Allerød warming period (Mott et al., 1986; Mott and

Stea, 1994; Stea and Mott, 1998). Stea and Mott (1998) conducted research on several lakes across Nova Scotia, through the Isthmus of Chignecto, and into New Brunswick, creating a paleogeographical reconstruction of deglaciation. Another study by Walker

(1980) provided a detailed pollen and chironomid-based regional climate record from

Wood’s Pond near Sackville, New Brunswick; however, the timing of changes seen in these records is not well constrained.

Two important studies on the landscape evolution were completed by Chalmers

(1895) and Ganong (1903) and collectively provided an evolutionary model for the

Border Marshes, as well as the possible formation of the lakes within the environment.

Chalmers (1895) and Ganong (1903) observed that the deposition of Bay of Fundy sediments occurs preferentially near the edges of salt marshes and river banks, which produces a topographical high along the coast. These two studies proposed that the

Cumberland Basin was a lake, surrounded by marshes and peat bogs that were influenced by sea level fluctuations (Chalmers, 1895; Ganong, 1903). It was also suggested that as the sea level rose and the land subsided, this area was converted into a salt marsh environment; where tidal water met freshwater, maximum deposition occurred, creating a natural dam in which the marshes, bogs, and wetlands could evolve (Ganong, 1903;

Figure 1.10). These wetlands (i.e. Tantramar Marsh, Missaguash Marsh, and Amherst

Marsh) formed in the natural topographical depressions inland. As the sea level continued to rise and the land continued to subside, the marsh surface would continue to aggrade

Figure 1.10 Ganong’s (1903) longitudinal modelled section of the marshes from the coast inland.

(Ganong, 1903; Shaw and Cemen, 1999). Several studies complement this model of marsh evolution. Trueman (1899) found tidal sediment underlying the lakes and bogs adjacent to the major rivers in the area (Tantramar River, Aulac River, and Missaguash

River) and Smith (1967) found evidence of a marine sediment layer under the marsh.

Trueman (1899) hypothesized during the last glacial period that the Chignecto Bay had been a valley and the Bay of Fundy had been dryland. This study indicated that this area was well above tidal influence post-glacially due to the presence of trees rooted in a soil horizon above a bed of red clay. The depression and consequent uplift of the land that followed the glacial period would have been the location for the accumulation of fine marine clays followed by the growth of forests and other terrestrial vegetation (Trueman,

1899). No explanation is offered as to how the coastal region was initially below high tide level, but Trueman (1899) proposed that salt water inundated up the valleys through constantly eroding and migrating marsh rivers.

MacNeill (1969) also proposed that the Tantramar Marsh and the surrounding marshes were an area of significant active erosion and deposition over the past several thousand years. MacNeill (1969) suggested that drainage channels through the marsh system into the Cumberland Basin were mobile and meandered significantly due to the rapid movement of water. This implies that the pathway for salt water inundation and salt marsh aggradation was variable. As previously mentioned, crustal subsidence, substantial tidal range increase, and natural eustatic sea level fluctuations are all important controlling factors on salt marsh aggradation on the Border Marshes (Shaw and Cemen,

1999). Shaw and Cemen (1999) stated that marsh aggradation has been occurring over

24 the past ~4,000 years, with two periods of rapid marsh aggradation at ~1,400 and 400 cal yr. B.P.

A study by Walker and Paterson (1986) investigated sedimentary diatom assemblages and associations for peat pools, strongly acidic lakes, and weakly acidic lakes (including the Jolicure Lakes) that are distributed across the Isthmus of Chignecto and surrounding areas in both New Brunswick and Nova Scotia. This research investigated the succession of lakes over time by relating diatom assemblages to the different water body categories (i.e. peat pools, shallow strongly acidic lakes, shallow weakly acidic lakes) (Walker and Paterson, 1986). The authors believed that the encroachment by migrating wetlands has had a significant impact on the lakes and water bodies on the Isthmus of Chignecto by eliminating several small freshwater lakes from within the lowland areas. They found that the natural physical and chemical succession of lakes can be characterized by different diatom assemblages (Walker and Paterson, 1986).

B.) Metals in the Border Marshes Region

A paleolimnological study of lake sediments in the three study lakes will provide an understanding of temporal concentrations of lead (Pb) and mercury (Hg) that are known to exist in the Border Marshes. These wetlands are known to have high concentrations of lead, which has been concentrated in waterfowl (Schwab and Daury,

1989). The primary source of lead is thought to be lead shot from shotgun shells (Schwab and Daury, 1989). Prior to 1999, lead poisoning was prevalent in a variety of species of waterfowl (Schwab and Daury, 1989; Health Canada, 2008). As a consequence, in 1999,

Environment Canada adopted the Migratory Birds Regulations, which prohibited the use of lead shot on migratory birds in Canada (Health Canada, 2008).

Little research has been conducted on long term lead dynamics in lake and wetland systems in the Border Marshes. Research on lakes and wetlands to the north of

Sackville, New Brunswick and west of Jolicure Lake noted that several of these habitats also had elevated levels of lead in their systems (Boyle, 1977). However, little is known about natural lead accumulation or whether other sources of lead beside lead shot may have contributed to lead concentrations in lake sediments on the Isthmus of Chignecto

(Boyle, 1977). Lake core lead concentrations are an effective archive of atmospheric or watershed pollutant inputs from both natural and anthropogenic sources (Cohen, 2003).

The study lakes are advantageously located to investigate lead contamination because they are located directly within the Nova Scotia-New Brunswick Border Marshes, providing an excellent perspective of both natural and anthropogenic lead concentrations in a natural environment.

Mercury concentrations in waterfowl in Eastern Canada have also been a concern;

Hg concentrations in loons within Nova Scotia were discovered to be the highest in North

America (6-7 ppm in loon blood; Pearce et al., 1976; Burgess et al., 1998; Evers et al.,

1998; Nocera and Taylor, 1998; Evers et al., 2007). Methyl mercury is a highly mobile and bioaccumulative toxin in the environment. Methyl mercury accumulation in an ecosystem is driven by two primary factors, 1) increased retention of mercury, which may eventually be methylated and 2) the rate of mercury methylation.

Atmospheric mercury deposition is typically the primary source of deposition into ecosystems and has increased since the industrial revolution, mainly due to the burning of fossil fuels, specifically coal for heat and energy, and the production of metals, chlorine, and cement (AMAP, 2005; O’Driscoll et al., 2005b). The global atmospheric mercury

26 pool is estimated at ~5 x 109 g, but this Hg is constantly being converted into more soluble forms and deposited (Fitzgerald, 1994). However, sources of Hg within lake and wetland ecosystems can be through the weathering of bedrock and till and groundwater input (O’Driscoll et al., 2005b). Once the mercury has been deposited within the lake ecosystem, several factors influence its transformation and bioaccumulation, including percentage of wetlands in the lake’s catchment basin, amount of dissolved organic matter, and lake acidity (St. Louis et al., 1994; Watras and Huckabee, 1994; Pettersson et al.,

1995; O’Driscoll et al., 2005b). Salt water inundation has also been found to affect the accumulation of mercury within an aquatic ecosystem. Laboratory studies have suggested that due to the increase in chloride levels attributed to salt water inundation, increased oxidation of mercury or stabilization of Hg(II) in freshwaters would occur; therefore, more retention of methylmercury in lake sediments would result (Poulain et al., 2007,

Qureshi et al., 2010).

The rate of mercury methylation is controlled by many variables. Studies on wetland and estuarine samples, have found that sulphate-reducing bacteria are not the primary producers of methyl mercury in areas where sulphate concentration is less than

10 mg/l (Choi and Bartha, 1994; Ingvorsen et al., 1981; Lovley and Klug, 1983). In wetland environments, these studies have also concluded that when sulphate reduction is not the primary factor governing methyl mercury production, the sediment organic matter

(increased levels of organic carbon) becomes a major factor (Choi and Bartha, 1994; Lee and Hultberg, 1990). Mercury methylation is especially prevalent in anoxic sediment systems (Lean, 2009). The high nutrient levels that may be present in the study lakes may contribute to anoxia and likely the availability and mobility of methyl mercury in this

27 environment (Nürnberg, 1995; Lean, 2009). Compiling baseline Hg data is important since little is known of mercury concentrations in the study region and there are still uncertainties regarding how mercury methylation occurs and is controlled naturally.

Jolicure Lake and Long Lake are located in fairly pristine locations, which implies that historical anthropogenic sources of contamination would be minimal. The study area is therefore well suited to the research of natural mercury mobility. Not only will these lake sediment cores provide baseline data and valuable information on mercury depositional and retention trends, but they will also provide a general modern day spatial trend across the Border Marshes region. The comparison of these modern spatial trends and historical temporal trends will enable a better understanding of the factors that influence mercury retention in lakes over time. In addition, it may provide insight into how these freshwater resources can be managed.

Chapter 2: Methodology

2.1 Introduction

This research focuses on reconstructing high resolution, multi-proxy records of paleoenvironmental change using lake sediments. The three study lakes were characterized by field data that were collected and processed during the summer and fall of 2011. Two cores were collected from each of the three study lakes; the longer core from each lake was sectioned, split lengthwise, and analyzed, while the shorter core was archived. The chosen cores were subsampled for lithostratigraphic and chemostratigraphic proxies to track paleoenvironmental change over the past ~10,000 years. The proxies used in this research include: loss on ignition (total organic carbon), magnetic susceptibility (allochthonous clastics indicator), C/N ratios and δ13C

(autochthonous or allochthonous organic material origin and paleosalinity), XRF elemental analysis (lead and chloride), and total mercury content (contaminants in the environment baseline data) (Table 2.1).

2.2 Modern Lake Characterization

A.) Water Quality

In order to understand paleoenvironmental change recorded in the lake sediment cores, the current physical characteristics of the lakes and watersheds from which the cores were collected were investigated. Various water quality parameters were obtained from each of the study lakes, including temperature, pH, dissolved oxygen, conductivity, and Secchi depth. Temperature, pH, dissolved oxygen, and conductivity were all measured using a YSI 650 MDS Display/Logger. These parameters were measured during the field season both at the surface and at the bottom depth at designated coring locations.

Method Description Interpretation

Relative determination of Higher values indicate Loss on Ignition organic carbon content higher organic matter (L.O.I.) within lake sediments content and lower clastic material

Higher values of magnetic Magnetic Susceptibility Presence of magnetic susceptibility indicate (M.S.) minerals (i.e. magnetite) higher levels of clastic input

C/N Ratio Relative input of aquatic and Aquatic: C/N ≤ 10 terrestrial organic matter Mixed: 10 ≤ C/N ≤ 20 Terrestrial: C/N ≥ 20

Freshwater Aquatics: C/N of 11-17; δ13C of -24.9‰- 32.5‰ C/N vs. δ13C Measure of paleosalinity Marine: C/N of 4-42; δ13C of ˃ -23‰ Terrestrial: C/N of 5-11 & 17-58; δ13C of -24.9‰- 32.5‰

Elevated δ15N indicates δ15N Potential indicator of forest forest fire activity and the fire occurrence release of inorganic nitrogen into the lake catchment

Major and trace element Chloride (Cl): paleosalinity X-Ray Fluorescence concentrations are valuable proxy tools in paleoenvironment Lead (Pb): concentration research data

Increased amounts of organic carbon have a major Concentration data and Mercury (Hg) Analysis role in the availability and potential indicator of mobility of mercury in warming periods wetland environments

Table 2.1 Descriptions and interpretations of proxies used in this research.

The trophic status of all three lakes was determined using Secchi depth, which is a standard, analytical means of determining relative trophic status (Wetzel, 1983). Water transparency, was measured using a 35 cm diameter Secchi disk on the shaded side of the watercraft. The Secchi disk was lowered until it was no longer visible and then raised until the disk reappeared. The two depth values were averaged to represent the Secchi depth.

B.) Lake Bathymetry and Sonar Profiling

Lake bathymetry was determined using the Contour 3D system with a 200 khz transducer and a Garmin GPS. A 50 kHz SyQwest Hydrobox paired with a Furuno

WAAS enabled GPS was used to determine the intrabasin sediment distribution within all three of the study lakes. Lake bathymetry and sediment distribution are not only important because they provide information on basin shape, but they can also be used to determine where to core the lake since basin shape influences sediment deposition

(Lennox et al., 2010). The Hydrobox was mounted to a 14 foot aluminum boat which was driven at a constant velocity along several transects across each of the three lakes.

2.3 Lake Sediment Collection and Analysis A.) Percussion Coring

Portable percussion coring is an important tool for paleolimnological and paleoenvironmental research since it provides a continuous sedimentary record. When sediment cores are split lengthwise changes in stratigraphy can be visually identified

(Gilbert and Glew, 1985; Reasoner, 1986; Reasoner, 1993; Glew et al., 2001). Two percussion cores were taken from each lake where the sediment distribution was thickest, as determined by lake bathymetry and sonar profiling. Percussion coring followed

31 procedures outlined in Reasoner (1993) and Lennox et al. (2010). Blair Lake was cored in the winter of 2010. Jolicure and Long Lakes were cored in June 2011 and required the construction of rafts to provide space and stability for successfully obtaining the percussion cores. The rafts were constructed using a 12 foot canoe, a small inflatable boat, a 2’’x 4’’ frame for structural support, and plywood for a solid surface with a hole in the centre for core barrel access.

B.) Core Preparation and Stratigraphy

All percussion cores were frozen after their retrieval to minimize sediment disturbance at the top of the core and transported to Acadia University. The longest cores from each lake were chosen for proxy analysis and were split lengthwise with a tile saw equipped with a ceramic blade. One half of the core was archived and the second half was covered in plastic wrap and sealed in plastic tubes, to prevent desiccation prior to proxy analysis. Before sampling occurred, the cores were photographed and visible stratigraphic changes were recorded based on colour using the Munsell colour system. The cores not chosen for proxy analysis were archived.

C.) Macrofossil 14C Dating

The geochronology and sedimentation rate within the three lake sediment cores were constrained by 5 14C accelerator-mass-spectrometry (AMS) dates from the

University of Arizona AMS Facility. Terrestrial samples were used for all 14C dates since aquatic organic matter has the potential to be effected by non-atmospheric carbon which generally produces an anomalously old date; this is known as the hard-water effect

(MacDonald et al., 1991; Kilian et al., 1999). Aquatic organic material can be contaminated by the incorporation of ancient carbon originating from the dissolution of

32 carbonate-rich geological deposits (Shotton, 1972; MacDonald et al., 1991; Kilian et al.,

1999). Samples for 14C dating were collected as close to the bottom of each core as possible to determine the minimum age of each lake and as close as possible to prominent stratigraphic boundaries to determine the timing of environmental transitions.

D.) Loss on Ignition

Loss on Ignition (L.O.I.) provides a relative determination of the organic carbon content within lake sediment and is traditionally used as an indicator of lake productivity

(Dean, 1974; Shuman, 2003). The loss on ignition method produces a rapid compositional profile of sediment core characteristics that can provide a general sense of core stratigraphy and can be used to correlate between cores (Dean, 1974). When using

Dean’s (1974) loss on ignition method, the results for organic content are typically accurate to ~1-2% in sediment with more than 5% organic content (Dean, 1974). On all lake cores, a modified 10 cm3 syringe was used to extract ~1 cm3 cylinders of sediment every ~5 cm depending on the stratigraphy. The samples were then placed into dry crucibles, weighed, dried for 16 hours at 105°C, and then re-weighed to determine water content. The samples were then heated at 550°C for four hours to remove all organic carbon material (Dean, 1974). The percent loss on ignition was calculated as the percentage of the dry weight of the sample that was lost during ignition at 550°C.

Duplicates were taken every ~20 cm.

E.) Magnetic Susceptibility

Magnetic susceptibility (M.S.) is a measure of the relative amount of terrestrial magnetic minerals present in lake sediment (i.e. magnetite; Nowaczyk, 2001; Hawthorne and McKenzie, 1993). Terrestrial magnetic material is much more prominent in lake

33 sediments than biogenic magnetic material, thus higher values of magnetic susceptibility represent an increase in clastic sediment input within a lake system (Hawthorne and

McKenzie, 1993). The most magnetically susceptible sediments contain the highest amount of allochthonous inorganic material washed into the lake from the drainage basin

(Wetzel, 2001). Magnetic susceptibility can also be used to indicate periods of anoxia since terrestrial magnetite can undergo reductive dissolution in anoxic environments

(Balascio et al., 2011). This dissolution reduces the magnetic susceptibility readings

(Balascio et al., 2011). The three cores chosen for analysis were elevated 20 cm high on a styrofoam base to reduce disturbance from ambient magnetic material. A hand-held KT-9

Kappameter was used to record two sets of 10 magnetic susceptibility values, which were averaged at ~5 cm resolution. To determine the experimental error of the magnetic susceptibility values, an additional set of 10 magnetic susceptibility values were measured and averaged every ~20 cm.

F.) Carbon and Nitrogen Analysis

The relative input of aquatic and terrestrial organic matter can be identified by the

%Carbon / %Nitrogen (C/N) ratio (Talbot, 2001; Meyers and Teranes, 2001; Kaushal and

Binford, 1999). The C/N ratio provides insight into the various sources of sedimentary organic matter deposited in the lake basin (Kaushal and Binford, 1999). Algal material is predominantly composed of N-rich lipids and proteins (C/N ≤ 10 = aquatic), whereas terrestrial organic material is predominantly composed of C-rich lignin and cellulose

(C/N ≥ 20 = terrestrial; Meyers and Teranes, 2001; Talbot, 2001). C/N ratios that are between 10 and 20 represent a mixture of aquatic and terrestrial material (Meyers and

Teranes, 2001; Talbot, 2001).

Preparation for carbon and nitrogen analysis (including δ13C, δ15N, %C, %N, and

C/N) was done in the same way as previous proxy analysis. δ13C was used as a paleosalinity indicator; this is further described in section 2.3.H. δ15N was used as a potential indicator for forest fire occurrences. Studies have shown that increased δ15N values can represent an elevated input of inorganic nitrogen from the surrounding catchment into a lake system after major forest fires (Amirbahman et al., 2004; Kelly et al., 2006). Samples were collected using the modified syringe and ~1 cm3 of lake sediment was dried for 16 hours at 105°C. The samples were then homogenized using a mortar and pestle and loaded into plastic vials. Forty samples were sent to the University of New Brunswick Stable Isotopes in Nature Laboratory (SINLAB), Fredericton, New

Brunswick. The SINLAB used Costech 4010 elemental analyzers that are interfaced to a

Finnigan Delta Plus mass spectrometer via the Conflo II and to a Finnigan Delta Plus XP mass spectrometer via the Conflo III. C/N ratios were only completed on Jolicure Lake and Long Lake cores due to financial constraints.

Stable isotope analysis is complex but is useful in any form of paleo- research.

δ13C is a measure of the ratio between stable isotopes 13C:12C, reported in parts per thousand (‰) (Stuiver and Reimer, 1998). δ13C varies through time as a function of vegetation type, organic carbon burial, and productivity(Stuiver and Reimer, 1998). The formula is as follows; where the standard material is based on a Cretaceous marine fossil, known as Pee Dee Belemnite (Stuiver and Reimer, 1998):

13 13 12 13 12 δ C = ([ ( C/ C)sample / ( C/ C)standard ] – 1) x 1000‰

δ13C excursions have different signatures; C3 plants have δ13C values between -33 and -

24‰ whereas C4 plants have δ13C values between -16 and -10‰ (Mackie et al., 2005 and

2007). δ15N is the measure of the ratio between 15N:14N, which is also reported in parts per thousand (‰) (Spencer et al., 2003a and b). Typically, the dominant source of nitrogen in forested ecosystems is the atmosphere (δ15N = 0‰). However, when forest fires occur there is an influx of inorganic nitrogen into the catchment basins, causing an increase in δ15N values (Amirbahman et al., 2004).

G.) Elemental Analysis

Elemental analysis has an important role in environmental research and can be a valuable tool in paleolimnology and paleoenvironmental reconstruction research when used in conjunction with other analytical procedures (Boyle, 1999; Last and Smol, 2001).

The X-Ray Fluorescence (XRF) method provided a rapid, non-destructive total elemental analysis of the lake sediments. In this study, an Olympus X-50 mobile XRF was used to collect elemental data and ~1 cm3 samples were collected using a modified syringe from the center of each core every ~5 cm with triplicates every ~20 cm (Boyle, 1999; Dr. Chris

White, N.S. Dept. Nat. Res.). The samples were dried overnight at 105°C and placed in plastic vials with plastic wrap across the top. They were then analyzed for chloride and lead in the XRF spectrometer using the 3-beam soil method (detection limits of 33 ppm and 2 ppm respectively; Olympus Corporation, 2011). With every triplicate, the last sample was analyzed three times in order to randomize the sample orientation to the X- ray beam and assess repeatability and reproducibility within samples. Chloride will be used as a paleosalinity marker; it is an inert and conservative element and has been shown to be a good indicator of salinity regimes (Branchu and Bergonzini, 2004). Other studies

36 indicate that chloride may be used to determine the proximity of the sample site to marine environments (Gorham, 1958). Lead is a significant toxic element in coastal wetland environments and was also determined (Schwab and Daury, 1989; Health Canada, 2008).

H.) Paleosalinity (δ13C)

δ13C was used in conjunction with C/N ratio as a paleoenvironmental indicator.

The carbon isotope concentration of marine, freshwater, and terrestrial plants is variable since they incorporate their carbon from different sources (Mackie et al. 2005).

Therefore, a biplot of C/N ratios and δ13C depicts unique data fields for terrestrial, freshwater, and marine organic materials (Galimov, 1985; Mackie et al., 2005; Mackie et al., 2007; Figure 2.1). However, the relationship between salinity and C/N vs. δ13C becomes less reliable within older sediments (i.e. last glacial maximum) (Mackie et al.,

2007). This is due to other environmental factors including poor vegetation development, temperature, and variable atmospheric CO2 concentrations that all exert significant influences on the δ13C values (Mackie et al., 2007).

I.) Mercury (Hg) Analysis

As previously discussed in 1.6.B., mercury concentrations are a concern in

Atlantic Canada and methyl mercury is of specific concern since it is highly mobile and bioaccumulative (Pearce et al., 1976; Evers et al., 2007). Atmospheric mercury deposition is usually the primary source of deposition into ecosystems and has increased since the industrial revolution (AMAP, 2005). The weathering of bedrock and till, and groundwater input are two other potential sources of Hg into a lake or wetland ecosystem

(O’Driscoll et al. 2005b). The percentage of wetlands, amount of dissolved organic

37 matter, and lake acidity control the transformation and bioaccumulation of deposited Hg

(Pettersson et al., 1995; O’Driscoll et al., 2005b).

Several recent studies have found that organic carbon and Hg concentrations in lake and wetland sediments are correlated, most likely due to warmer conditions resulting in the deposition of more autochthonous organic material as primary productivity increases (Choi and Bartha, 1994; Lee and Hultberg, 1990; Outridge et al., 2007; Kirk et al., 2011). Therefore, increased post-industrialization mercury levels within the sediment cores may relate to warming periods and increased organic sedimentation, but may also be associated with increased atmospheric deposition (Kirk et al., 2011). The lake sediment records provide an opportunity to examine the relationship between environmental change and mercury mobility and availability in wetland ecosystems.

The sediment cores were analyzed for mercury in order to determine baseline and pre-historic Hg levels. Approximately one hundred, 1 cm3 samples were obtained using the modified 10 cm3 syringe and were then dried overnight (16 hours) at 105°C. These samples were analyzed using thermal decomposition gold amalgamation atomic absorbance (Nippon Instruments Corporation MA-2000). Quality assurance included calibration, reagent blanks, and standard reference material (MESS). The MA-2000 has ultra-high sensitivity and blanks below the low detection limit of 0.002 ng Hg and high detection limit of 1000 ng Hg. Sample triplicates were analyzed every ~20 cm. Mercury analysis was only completed on the Jolicure Lake and Long Lake cores due to financial constraints.

Figure 2.1 C/N versus δ13C biplot showing the unique data fields. C/N values of 11-17 and δ13C values between -24.9‰-32.5‰ represent freshwater aquatics. C/N values between 4-42 and δ13C values greater than -23‰ represent marine material. C/N values between 5-11 and 17-58 and δ13C values of -24.9‰-32.5‰ represent terrestrial material (Galimov, 1985; Meyers and Lallier-Verges, 1999; Mackie et al., 2005; Mackie et al., 2007).

Chapter 3: Results and Interpretation

3.1 Regional Water Quality

The three study lakes, Jolicure Lake, Long Lake, and Blair Lake, are located within 12 km from the Chignecto Bay along the Isthmus of Chignecto. All three lakes are bounded by freshwater marshes and wetlands and are considered to be shallow lakes

(maximum depths between 1.9 m - 4.6 m). Overall, these lakes have pH values close to neutral (ranging between 6.52 - 8.12) due to the alkaline buffering qualities within the surrounding environment, specifically the Balfron, Middleborough, and Shepody formations, since rain water in Nova Scotia typically has a pH of ~4.7 (Environment

Canada, 2012). The lakes in this region have high dissolved oxygen values and low

Secchi depths. Conductivity within these lakes is relatively low with the exception of

Blair Lake implying the presence of higher dissolved ions which is likely due to significant anthropogenic influence at this site.

Jolicure Lake Long Lake Blair Lake (2.0 m max depth) (1.9 m max depth) (4.6 m max depth) Temperature 19.2°C 20.1°C 21.5°C

pH 6.52 7.05 8.12

Conductivity 42 µS/cm 40 µS/cm 397 µS/cm

Secchi Depth 0.85 m 0.72 m 0.46 m

Table 3.1 Averaged water quality parameters for all three study lakes. Data was acquired from May-August 2011.

3.2 Carbon Dating

The radiocarbon dating results for all three lakes are valid as shown by the

agreement between δ13C values and the material sampled. C3 plants, which are woody,

round-leafed plants, fix CO2 to a 3 carbon sugar (JL082011-C1-13, LL082011-C2-39,

LL082011-C2-87, and LL082011-C2-124; -24.4, -29.4, -27.0, and -26.7 respectively).

These plants typically have δ13C values between -33 and -24‰. C4 plants, which are land

plants, grasses, sedges, and grains, fix CO2 to a 4 carbon sugar (BL082011-C2-50;

-14.9‰). These plants typically have δ13C values between -16 and -10‰.

Core Lab Sample Depth Material δ13C Age Calendar Age Calendar Number (cm) (‰) (14C yr. (2σ) (cal. yr. Range (2σ) B.P.) B.P.) (cal. yr. BP terrestrial JL-1 JL082011- 140 leaf -24.4 3,860 3,775 3,726 - C1-13 fragment +/- 200 3,824

LL-2 LL082011- 94 wood -29.4 9,148 +/- 10,355 10,225- C2-39 fragment 49 10,484

LL-2 LL082011- 46 wood -27.0 4,396 +/- 5,064 4,850-5,278 C2-87 fragment 55

LL-2 LL082011- 9 twig -26.7 623 +/- 605 550-660 C2-124 34 terrestrial BL-2 BL082011- 226 grass -14.9 3,147 +/- 3,327 3,082-3,572 C2-50 fragment 86

Table 3.2 Compiled radiocarbon data for all three study lakes. All radiocarbon analyses took place at the University of Arizona AMS Laboratory, Tuscon, Arizona. Calibrated ages are given as mean calendar years (Stuiver and Reimer, 1993; Reimer et al., 2009).

3.3 Proxy Analysis

A. Jolicure Lake

I. Results a.) Modern Lake Characterization

i.) Field Observations

Jolicure Lake is located 11 km north of the Chignecto Bay, near sea level (Figure

1.1 and 1.3). It is bounded by the freshwater marshes and wetlands of the Tintamarre

National Wildlife Area along the southwestern lake boundary. Maritime Acadian Forest and some cultivated land are located along the northeastern lake boundary. Sediments from the middle Jolicure Lake were analyzed in this study; it is one of three lakes that are connected by man-made canals (Figure 1.3). All three lakes have been significantly altered over the past 50 years (MacKinnon, per. com., 2011). The Jolicure Lake system was a significant habitat for resident and migratory waterfowl, however, since the alterations, the waterfowl have relocated to nearby, man-made freshwater impoundments

(Maillet et al., 1999; MacKinnon, per. com., 2011). Waterfowl hunting is common in the area (MacKinnon, per. com., 2011). The lakes system is a popular recreation destination and canoes and small watercrafts are common on the lake.

ii.) Water Quality

Water quality data for Jolicure Lake was collected on May 10th, June 14th and 21st, and July 10th and 26th, 2011 (Table 3.1). The weather conditions preceding these surveys were generally fair, sunny, with few clouds, and temperatures between 15-20°C. For all field sessions, there was a light wind coming from the S-SW.

Average Values Temperature 19.2°C pH 6.52 Dissolved Oxygen 98% Conductivity 42 µS/cm Secchi Depth 0.85 m Table 3.3 Average measured water quality parameters for Jolicure Lake, collected throughout field season (May-July, 2011).

Jolicure Lake is a shallow lake with an average depth of 1.3 m and a maximum depth of 2.0 m. The pH in the lake is close to neutral (6.52). Due to its shallow depth and exposure to wind, the lake does not stratify. Dissolved oxygen levels are high (average of

98%) and conductivity values are low (average of 42 µS/cm). This lake has a dark brown colour, which likely indicates high organic content in the water column; the Secchi depth was 0.85 m. Jolicure Lake’s water has a low residence time due to the lake’s overall shallowness, as well as the connectivity and through-flow of water through the two other adjacent lakes and wetland systems (Ambrosetti et al., 2003).

iii.) Basin Morphometry and Sediment Distribution

The bathymetric map was constructed using data derived from the Contour 3d system and the sonar profile was constructed using data derived from the Hydrobox

(Figure 3.1). The sonar profile is represented by the A-A’ line. b.) Stratigraphy and Age of Sediment

i.) Lake Sediment Cores

All cores were taken from the deepest location of the lake based on bathymetry and sonar data. Two percussion cores were obtained from Jolicure Lake on June 21st,

2011. JL-1 was 1.53 m in length and was chosen for detailed study as it was the longer of

Figure 3.1 Jolicure Lake bathymetry (top panel) and sonar transect A-A’ (bottom panel). Coring location is represented by the black circle on the bathymetry map. The approximate coring location is depicted across the A-A’ transect with likely zonation indicated by the dashed lines. The fine dashed line likely represents basin bottom.

44 the two cores and likely contained the longest post-glacial record. JL-2 was 1.49 m in length and was archived.

ii.) Dating

One radiocarbon date was obtained for Jolicure Lake (Table 3.2). Sample

JL082011-C1-13 was obtained at 140 cm depth (length=13 cm) and was identified as terrestrial leaf material. This sample yielded a calibrated age of 3,775 cal. yr. B.P.

(Stuiver and Reimer, 1993; Reimer et al., 2009).

Core Lab Depth Material δ13C Age Calendar Age Calendar Sample (cm) (14C yr. (2σ) (cal. yr. Range (2σ) Number B.P.) B.P.) (cal. yr. BP) terrestrial JL-1 JL082011- 140 leaf -24.4 3,860 3,775 3,726 - 3,824 C1-13 fragment +/- 200 Table 3.4 Jolicure Lake radiocarbon ages. All radiocarbon analyses took place at the University of Arizona AMS Laboratory, Tuscon, Arizona. Calibrated ages are given as mean calendar years (Stuiver and Reimer, 1993; Reimer et al., 2009).

iii.) Lithostratigraphic Units (Figure 3.2 and 3.3)

Seven distinct lithostratigraphic units were visually identified in core JL-1. The basal unit (JL-Unit 1; 153-134 cm) is a brown clay-rich sediment (Hue 7.5 YR 4/3). This lithostratigraphic unit is characterized by L.O.I. values (average 4% organic carbon content) and relatively high M.S. values (averaging 0.11 SI units). This unit grades into a very dark bluish gray, clay-rich sediment (JL-Unit 2; 134-130 cm; Gley hue 5B 4/1). JL-

Unit 3 (130-103 cm) is an increasingly organic unit and exhibits several oscillations between dark gray gyttja (Hue 7.5 YR 3/1) and black gyttja (Hue 7.5 YR 2.5/1). The

L.O.I. values increase steadily in this unit with a maximum value at 25.5% organic carbon content at 103 cm, whereas, the M.S. values decline steadily to 0.016 SI units. JL-

Unit 3 is overlain by a gray clay-rich sediment (JL-Unit 4; 103-79 cm; Hue N4/). JL-Unit

Figure 3.2 Jolicure Lake Lithostratigraphic Units (scale in cm).

4 exhibits a slight increase in L.O.I. and decrease in M.S. and is in diffuse contact with

JL-Unit 5 (79-35 cm). JL-Unit 5 is a dark reddish brown gyttja (Hue 7.5 YR 3/2) that has very low L.O.I. (average 4.6%) and generally higher M.S. values (average 0.10 SI units).

The overlying unit (JL-Unit 6; 35-21 cm) grades into JL-Unit 5. This unit begins as a

Figure 3.3 Jolicure Lake stratigraphic and multi-proxy results. The record spans >3,775 calibrated years before present. Four paleolimnological zones were identified.

47 very dark brown gyttja (Hue 7.5 YR 2.5/2) and grades into a dark brown/black, increasingly organic gyttja (Hue 7.5 YR 2.5/1). The L.O.I. values increase (average 18%) and the M.S. values decrease to an average of 0.02 SI units. The upper most unit (JL-Unit

7; 21 cm-Top of Core) is a clastic, reddish brown gyttja (Hue 7.5 YR 4/3). JL-Unit 7 exhibits a decrease in L.O.I. (average 13%) and a subtle increase up core in M.S. values

(average 0.04 SI units). c.) Chemostratigraphic Results (Figures 3.3 and 3.4)

i.) Carbon/Nitrogen Ratio

The Carbon/Nitrogen (C/N) Ratio is generally stable throughout JL-1 with an average value of 10.8. The basal sediments from 153-128 cm, exhibit an increasing trend from 5.7 to 13.4, followed by a period of little change (128-40 cm) with an average C/N ratio of 10.4. During this period, there is an isolated value of 19.34 at 88 cm. The upper most portion of the core exhibits a subtle trend of increasing C/N values which stabilizes with an average value of 13.4.

ii.) Paleosalinity (Chloride and C/N vs. δ13C)

Chloride (Cl) values throughout JL-1 core average 1,332 ppm. There are three high values of Cl at 135 cm, 60 cm, and 48 cm with values of 6,879 ppm, 13,166 ppm, and 7586 ppm respectively. The biplot of C/N vs. δ13C shows three distinct groups within the data (Figure 3.4). From 153-130 cm, the δ13C data plots between -24.9‰ and -32.5‰, while the C/N values are below 8. The second distinct group appears between 130-103 cm and 40 cm-Top of Core and also has δ13C values within -24.9‰ and -32.5‰, however the C/N values are between 11 and 18. The final group of data (103-40 cm) has δ13C values between -14‰ and -21.7‰, while the C/N values are between 4 and 42.

iii.) Lead and Mercury Concentrations

Lead (Pb) and mercury (Hg) display an asynchronous trend through most of the

JL-1 core. During the interval of 153-103 cm, Pb values decrease from 10 ppm to 2 ppm, while Hg levels increase from 29 ppb to an average of 76 ppb. From 103-40 cm, Pb values increase and stabilize (average of 12 ppm) and Hg values decrease and stabilize at an average value of 13.7 ppb. The uppermost sediment does not exhibit an asynchronous relationship between the two metals. From 40 cm-Top of Core, Pb values are variable and increase to a maximum value of 16 ppm. Hg values also increase during this interval to a maximum value of 150 ppb.

Figure 3.4 Jolicure Lake C/N vs. δ13C biplot (Mackie et al., 2005; Mackie et al., 2007)

II. Interpretation (Figures 3.3 and 3.4)

Modern Lake Characteristics

Water quality assessment indicates that Jolicure Lake is currently a shallow, dystrophic freshwater lake. Low depth and exposure result in constant water column mixing and for sediment resuspension.

Zone 1: Nascent Lake Phase;153-134 cm; 4,500-3,500 cal. yr. B.P.

JL-Zone 1 represents a period of low productivity and higher clastic input with a predominantly terrestrial influence. Basal, clay-rich sediment, low L.O.I., and high M.S. values indicate that the lake and watershed were not productive. This observation is supported by previous post-glacial limnological studies that have found clay-rich, highly magnetic sediment ("glacial flour") deposited on top of coarse-grained glacial outwash sediments (Rosenbaum and Reynolds, 2004). C/N values during this interval represent a mixed terrestrial and aquatic influence (Meyers and Teranes, 2001). However, the results from the C/N vs. δ13C biplot indicate that this zone represents a time of predominantly terrestrial organic carbon influx (Mackie et al., 2005). Chloride values are higher than typical freshwater environments (average of 1691 ppm; Gorham, 1958; IAEA, 2004), but relatively low in comparison with the entirety of the Jolicure Lake core. Higher background salinity readings for this lake and others in this region are possible due to their proximity to the ocean and the potential for sea spray to be transported by wind and precipitation (Gorham, 1958; Underwood, et al., 1981).

Hg and Pb concentrations through this zone are asynchronous and appear to correlate with organic and clastic content respectively (r2=0.72 and 0.66 for Hg and

L.O.I.; r2=0.70 and 0.71 for Pb and M.S.; Appendix 4). Both L.O.I. and Hg values increase through this zone. This similarity is to be expected as available Hg readily complexes with organic material, implying that biological activity may be a dominant process in mercury retention (Ahn et al., 2010; O’Driscoll et al., 2011). In this zone, Pb and M.S. (clastic content) concentrations decrease. The source of the background Pb levels within this nascent lake phase could be from Pb-rich clastic material from underlying strata, transported to this location by glaciers (Stea, 1982; Foisy and

Prichonnet, 1991). Likely bedrock sources include the late Carboniferous terrestrial Mt.

Whatley deposit and the Green Creek North deposits (N.B. Dept. Nat. Res., 2002).

However, Pb commonly binds to organic material and in Zone 1, this was not the case

(Aleksander-Kwaterczak and Kostka, 2011).

Zone 2: Lacustrine Phase I; 135-103 cm; 3,500-2,000 cal. yr. B.P.

JL Zone 2 represents a period of increased productivity as indicated by the increase in L.O.I. values and decrease in M.S. values. The C/N values (which fluctuate between 10-20) indicate both a terrestrial and an aquatic carbon contribution (Meyers and

Teranes, 2001). However, the C/N vs. δ13C biplot indicates that the input material is predominantly freshwater aquatic material (Mackie et al., 2005; Mackie et al., 2007). The

Cl concentrations do not indicate a major salt water influence during this zone (IAEA,

2004).

Hg and Pb values reflect fluctuations in organic content and are consistent with the process of available Hg complexing with organic material (Lepane et al., 2007; Ahn et al., 2010). Pb concentrations appear to be associated with clastic influx and likely

51 indicate that lead in the system is originating from a detrital source (Aleksander-

Kwaterczak and Kostka, 2011).

Zone 3: Open Marine Phase; 103-39 cm; 2,000-800 cal. yr. B.P.

JL Zone 3 represents a period of reduced productivity and salt water influence.

L.O.I. values decrease significantly and rapidly, indicating a decline in productivity. M.S. values are generally elevated with fluctuations likely indicating periods of elevated clastic input. The C/N ratios remain in the 10-20 range, indicating that both terrestrial and aquatic organic sources were contributing to organic sedimentation (Meyers and Teranes,

2001). At 60 cm and 48 cm, Cl is elevated indicating possible salt water egress into the system (Gorham, 1958). The C/N vs. δ13C biplot of data derived in this zone indicates a marine source for the carbon (Mackie et al., 2005). Hg and Pb continue to be associated with organic and clastic content respectively. A decline in Hg concentrations correlates with a decrease in L.O.I and an increase in M.S. correlates with an increase in Pb values

(r2=0.72 and 0.66 for Hg and L.O.I.; r2=0.70 and 0.71 for Pb and M.S.; Appendix 4).

Zone 4: Lacustrine Phase II; 39 cm-Top of Core; 800 cal. yr. B.P. to the present

JL Zone 4 represents a period of increasing productivity under predominantly freshwater conditions. High L.O.I., low M.S., and C/N values between 10 and 20 indicate sustained autochthonous productivity (Meyers and Teranes, 2001). Cl values of ˂1,000 ppm are consistent with freshwater systems and likely indicate that significant salt water input did not take place (Gorham, 1958; Branchu and Bergonzini, 2004). The C/N vs.

δ13C biplot also indicates that the organic sediment likely originated in a freshwater aquatic environment (Mackie et al., 2005).

Hg and Pb trends indicate a variety of possible environmental scenarios within this zone. L.O.I. concentration trends are similar to Hg signifying that available Hg readily complexes with organic matter (Lepane et al., 2007; Ahn et al., 2010). However, the increase in Hg at the top of the core as L.O.I. begins to decrease is unexpected but may be related to anthropogenic releases from fossil fuel burning (O’Driscoll et al.,

2005a and 2005b).

B. Long Lake

I. Results a.) Modern Lake Characterization

i.) Field Observations

Long Lake is located 9 km northeast of the Chignecto Bay, near sea level (Figure

1.1 and 1.4). It is bounded by managed freshwater marshes and wetlands along the southern lake boundary. Maritime Acadian Forest is located along the northeastern and northwestern lake boundaries (Figure 1.4). On the forested shorelines, sediment was mineralogically immature, well-sorted, and sandy. Access to Long Lake and the 10 residential camps was through old logging roads. Long Lake is used recreationally by motorboats, canoes, and other non-motorized watercraft. Fishing and hunting is common in the area (Lusby, per. com. 2011).

ii.) Water Quality

Water quality data for Long Lake was collected on May 11th and 16th, June 23rd and 27th, and July 7th, 8th, and 25th, 2011 (Table 3.3). The weather conditions preceding these surveys were overall fair, sunny, with few clouds, and temperatures between 15-

20°C. There was a always wind coming from the S-SW. On May 16th, bathymetry and sonar work was carried out in overcast conditions and some rain showers.

Long Lake is a shallow lake with an average depth of 1.2 m and a maximum depth of 1.9 m. It exhibits similar water quality parameters to Jolicure Lake. pH in the lake is neutral (7.05). Due to its shallow depth and exposure to wind, the lake does not stratify. Dissolved oxygen levels are high and over the course of monitoring averaged

108% and conductivity values are low, averaging 40 µS/cm. The Secchi depth was 0.72 m and the lake has a dark brown colour, which likely indicates high organic content and sediment resuspension in the water column. Long Lake’s water likely has a low residence time due to the lake’s overall shallowness, as well as the connectivity and through-flow of water through the adjacent marsh and wetland systems (Ambrosetti et al., 2003).

Average Values Temperature 20.1°C pH 7.05 Dissolved Oxygen 108% Conductivity 40 µS/cm Secchi Depth 0.72 m

Table 3.5 Average measured water quality parameters for Long Lake, collected throughout the field season (May-July, 2011).

iii.) Basin Morphometry and Sediment Distribution

The bathymetric map was constructed using data derived from the Contour 3d system and the sonar profile was constructed using data derived from the Hydrobox. The sonar profiles are represented by the A-A’ and B-B’ lines (Figure 3.5).

Figure 3.5 Long Lake bathymetry and sonar profiles A-A’ and B-B’. Coring location is represented by the black circle on the bathymetry map. The approximate coring location is depicted across the A-A’ transect with likely zonation indicated by the dashed lines.

55 b.) Stratigraphy and Age of Sediment

i.) Lake Sediment Cores

All cores were taken from the deepest location of the lake based on bathymetry and sonar data. Two percussion cores were obtained from Long Lake on June 24th, 2011.

LL-1 was 1.26 m in length and was archived. LL-2 was 1.33 m and was chosen for detailed study as it likely contained the longest post-glacial record.

ii.) Dating

Three radiocarbon dates were obtained for Long Lake (Table 3.4). Sample

LL082011-C2-39 was obtained at 94 cm depth (length = 39 cm) and was identified as wood. This sample yielded a calibrated age of 10,355 cal. yr. B.P. (Stuiver and Reimer,

1993; Reimer et al., 2009). LL082011-C2-87 was obtained at 46 cm depth (length = 87 cm) and was identified as wood. This sample yielded a calibrated age of 5,064 cal. yr.

B.P. (Stuiver and Reimer, 1993; Reimer et al., 2009). LL082011-C2-124 was obtained at

9 cm depth (length = 124 cm) and was identified as a twig. This sample yielded a calibrated age of 605 cal. yr. B.P. (Stuiver and Reimer, 1993; Reimer et al., 2009).

Core Lab Sample Depth Material δ13C Age Calendar Age Calendar Number (cm) (14C yr. (2σ) Range (2σ) B.P.) (cal. yr. B.P.) (cal. yr. B.P.)

LL-2 LL082011- 94 wood -29.4 9,148 +/- 10,355 10,225- C2-39 fragment 49 10,484

LL-2 LL082011- 46 wood -27.0 4,396 +/- 5,064 4,850-5,278 C2-87 fragment 55

LL-2 LL082011- 9 twig -26.7 623 +/- 605 550-660 C2-124 fragment 34

Table 3.6 Long Lake radiocarbon ages. All radiocarbon analyses took place at the University of Arizona AMS Laboratory, Tuscon, Arizona. Calibrated ages are given as mean calendar years (Stuiver and Reimer, 1993; Reimer et al., 2009).

iii.) Lithostratigraphic Units (Figure 3.6 and 3.7)

The stratigraphy of LL-2 is less variable than both Jolicure Lake and Blair Lake; however there are three distinct lithostratigraphic units. The basal unit (LL-Unit 1; 133-

106 cm) is reddish brown sandy (Hue 5 YR 4/4). The L.O.I. values within this unit are

<1% organic carbon content and the M.S. values varied from 0.05 SI units to 0.02 SI units. LL-Unit 1 is overlain by a very dark brown to black gyttja (LL-Unit 2; 106-9 cm;

Hue 5 YR 4/4/5 YR 3/4) gyttja (Figure 3.5). The contact between LL-Unit 1 and LL-Unit

2 is abrupt. The L.O.I. values increase rapidly and remain high throughout LL-Unit 2

(average of 90%). M.S. values remain low through LL-Unit 2 (average 0.01 SI units).

This unit has a wood rich section (50-24 cm) that begins at approximately 5,064 cal. yr.

B.P., likely indicating landscape disturbance (i.e. forest fire). LL-Unit 2 is overlain by

LL-Unit 3 (9 cm-Top of Core), which is dark brown gyttja (Hue 7.5 YR 3/2) and begins at 605 cal. yr. B.P. The L.O.I. values significantly decrease to 17% and the M.S. values increase up core to at 0.03 SI units. c.) Chemostratigraphic Results (Figure 3.7 and 3.8)

i.) Carbon/Nitrogen Ratio

The Carbon/Nitrogen (C/N) Ratio has three distinct trends in core LL-2. Unit 1

(133-85cm) is characterized by values that increase from 2.8 to 30.2. Gyttja from 85-11 cm exhibits little variability with an average C/N ratio of 25.5. C/N values in the upper most portion of the core (11 cm-Top of Core) decrease from 25.5 to 15.4.

ii.) Paleosalinity (Chloride and C/N vs. δ13C)

Chloride (Cl) values throughout LL-2 average 1,921 ppm. There are two high values of Cl at 83 cm and 68 cm with values of 30,924 ppm and 20,165 ppm respectively.

Figure 3.6 Long Lake Lithostratigraphic Units (scale in cm).

The biplot of C/N vs. δ13C shows three distinct groups within the data (Figure

3.8). Within the interval of 133-108 cm, the δ13C data plots between -24.9‰ and -32.5‰, while the C/N values are below 8. The second group of data (108-85 cm, 11cm-Top of

Core) contains δ13C data values between -24.9‰ and -32.5‰, while the C/N values are between 11 and 18. The final group of data (85-11 cm) has δ13C values between -24.9‰ and -32.5‰, while the C/N values are between 5 and 58.

Figure 3.7 Long Lake stratigraphic and multi-proxy results. The record spans >10,355 calibrated years before present. Four paleolimnological zones were identified.

iii.) Lead and Mercury Concentrations

Lead (Pb) and mercury (Hg) display an asynchronous trend within the LL-2 core.

During the interval of 133-108 cm, Pb values decrease from 6ppm to 2 ppm, while Hg levels show little variability and average 1.5 ppb. From 108-11 cm, Pb values are consistent at 2 ppm and Hg values increase to an average of 102 ppb. There are elevated values of Pb and Hg through this zone with values of 8 ppm Pb at 48 cm and 870 ppb Hg at 53 cm. The upper most sediment (11 cm-Top of Core) exhibits a significant increase in

Pb values to a maximum value of 8 ppm, while Hg values decrease to 67 ppb.

Figure 3.8 Long Lake C/N vs. δ13C biplot (Meyers and Lallier-Verges, 1999; Mackie et al., 2005; Mackie et al., 2007).

II. Interpretation (Figure 3.7 and 3.8)

Modern Lake Characteristics

Limnological assessment indicates that Long Lake is currently a shallow, dystrophic freshwater lake. Shallow depth results in constant water column mixing and the potential for sediment resuspension due to wind and wave activity.

Zone 1: Post-Glacial Basin, Pre-Lacustrine Phase; 133-108 cm; ~13,000-11,500 cal. yr. B.P.

LL Zone 1 represents a period of low productivity and significant clastic sediment input. The coarse grained sand to gravel-sized sediment in this zone is similar to sediment exposed along the shoreline of the lake that is believed to be glacial lacustrine, sandy till

(Rampton, 1984). However, C/N values during this interval indicate an aquatic influence, with values less ˂10. Chloride values of ˂1000 ppm are consistent with fresh water systems and likely indicate that significant salt water influence did not occur during this time (Branchu and Bergonzini, 2004).

Hg and Pb concentrations thorough this zone are asynchronous and appear to correlate well with organic and clastic content respectively (r2=0.72 and 0.66 for Hg and

L.O.I.; r2=0.70 and 0.71 for Pb and M.S.; Appendix 4). Both L.O.I. and Hg are very low which is to be expected as available Hg readily complexes with organic material (Ahn et al., 2010; O’Driscoll et al., 2011). Pb and M.S. (clastic content) concentrations are high.

The higher Pb levels within this post-glacial, pre-lacustrine interval could be derived from glacial till that contains Pb-rich clasts, transported from primarily north-northwest glacial flow (Stea, 1982; Foisy and Prichonnet, 1991). Likely bedrock sources include the late Carboniferous terrestrial Mt. Whatley deposit and the Green Creek North deposits

(N.B. Dept. Nat. Res., 2002). However, this trend is contrary to results from research by

Aleksander-Kwaterczak and Kostka (2011), since Pb was found to commonly bind to organic material.

Zone 2: Nascent Lake Phase; 108-93 cm; 11,500-10,355 cal. yr. B.P.

LL Zone 2 represents a period of increased watershed productivity and the establishment of a freshwater lake environment as indicated by the significant increase in

L.O.I. values and overall decrease in M.S. values. The C/N values (between 10-20) indicate that both terrestrial and aquatic carbon sources contributed to lake sedimentation

(Meyers and Teranes, 2001). However, the C/N vs. δ13C biplot indicates that the aquatic carbon likely has a strong freshwater affinity (Mackie et al., 2005). The Cl concentrations are low and likely indicate that salt water egress did not occur during this interval

(Branchu and Bergonzini, 2004).

Hg values are similar to L.O.I. values, which is consistent with the process of available Hg readily complexing with organic matter (Lepane et al., 2007; Ahn et al.,

2010; O`Driscoll et al., 2011). Pb concentrations again appear to be associated with M.S. and clastic input, indicating that the lead in the system is likely detrital in origin.

Zone 3: Lacustrine Phase I; 93-11 cm; 10,355-605 cal. yr. B.P.

LL Zone 3 represents a period of increased allochthonous productivity and rapid organic sedimentation. The average L.O.I. value for this zone is 93% and M.S. values are low. C/N values are greater than 20, indicating predominantly sustained allochthonous, terrestrial organic input (Meyers and Teranes, 2001). The C/N vs. δ13C biplot also supports this interpretation with values plotting within the C3 plant range (Meyers and

Lallier-Verges, 1999; Mackie et al., 2005). Cl values are generally low throughout this

62 zone; however there are two high values at ~8,000 cal. yr. B.P. The C/N vs. δ13C biplot data do not support the Cl spikes for prolonged salt water inundation.

Pb and Hg concentrations are generally both low throughout LL Zone 3; however, isolated high Hg and Pb values occur at ~5,000 cal. yr. B.P. During this time, the climate was warmer and precipitation was lower (the Hypsithermal climate period) and an increased incidence of forest fires would be likely (Railton, 1975a&b; Ali et al., 2009).

Forest fires commonly result in significant mobilization of cations concentrated in forest biomass, which are then transported to lakes by surface and groundwater runoff. This process could increase both nutrient and metal deposition into the lake basin (Kelly et al.,

2006).

Zone 4: Lacustrine Phase II; 11 cm-Top of Core; 605 cal. yr. B.P. to the present

LL Zone 4 represents a period of reduced terrestrial productivity during freshwater aquatic conditions. L.O.I. values decrease and M.S. values increase, indicating increased clastic input. C/N values fluctuate between 10 and 20, indicating sustained autochthonous productivity and the C/N vs. δ13C biplot also indicates that the organic carbon is predominantly from a freshwater aquatic source (Meyers and Teranes, 2001;

Mackie et al., 2005). Cl values of ˂1,000ppm are consistent with freshwater systems and likely indicate that significant salt water input did not take place (Gorham, 1958; Branchu and Bergonzini, 2004). As expected, decreasing Hg values correlate with decreasing

L.O.I. values (r2=0.72 and 0.66; Appendix 4; Lepane et al., 2007; Ahn et al., 2010). The

Pb values increase significantly as M.S. increases and may indicate the introduction of an anthropogenic lead source transported atmospherically to the site (r2=0.70 and 0.71;

Appendix 4; Weiss et al., 2002; Terry, 2011).

C. Blair Lake

I. Results a.) Modern Lake Characterization

i.) Field Observations

Blair Lake is located 4 km east of the Chignecto Bay, near sea level. It is bounded by freshwater marshes and wetlands along the southern lake boundary and Acadian

Maritime Forest and residential development (Loch Lomond RV Park) along the rest of the lake boundary (Figure 1.1 and 1.5). The Trans Canada Highway is located directly north of Blair Lake (Figure 1.5). Blair Lake watershed is characterized by mixed commercial, residential, and rural development and the lake itself is used for a variety of recreational activities. Periods of high productivity and sustained poor water quality have been well documented (Taylor, 2005). The surface water at the time of sampling was highly turbid, bright green, with a strong odour likely due to excess algae in the water column. Large algal blooms have been previously documented within Blair Lake in the

2005 Blair Lake Water Quality Assessment (Taylor, 2005).

ii.) Water Quality

Water quality data for Long Blair Lake was collected on May 29th, June 27th, July

5th, 10th, and 24th and August 14th, 2011. The weather conditions preceding these surveys were fair, sunny, with few clouds, and temperatures in the mid 20°C. There was always a noticeable wind coming from the S-SW.

Blair Lake is the deepest of the three study lakes with an average depth of 3.1 m and a maximum depth of 4.6 m. This lake is eutrophic and has a slightly basic pH of 8.12.

Blair Lake also has high conductivity (397 µS/cm). This study lake is productive and

64 algal blooms were observed during field surveys. During this study, Secchi depths were consistently low, averaging 0.46 m. Wave heights of >0.7 m were observed under moderate wind conditions, indicating that surface water mixing is common. Blair Lake’s water has a low residence time due to the lake’s connectivity and through-flow of water throughout the adjacent marsh and wetland systems (Ambrosetti et al., 2003).

Average Values Temperature 21.5°C pH 8.12 Dissolved Oxygen 110% Conductivity 397 µS/cm Secchi Depth 0.46 m

Table 3.7 Average measured water quality parameters for Blair Lake, collected throughout the field season (May-August, 2011).

iii.) Basin Morphometry and Sediment Distribution

The bathymetric map was constructed using data derived from the Contour 3d system and the sonar profile was constructed using data derived from the Hydrobox

(Figure 3.9). The sonar profiles are represented by the A-A’ and B-B’ lines. b.) Stratigraphy and Age of Sediment

i.) Lake Sediment Cores

All cores were taken from close to the deepest location within the lake basin as determined by bathymetry and sonar data. Two percussion cores were obtained from

Blair Lake on January 6th, 2011. BL-1 was 2.57 m in length and was archived. BL-2 was

2.76 m in length and was chosen for detailed study.

Figure 3.9 Blair lake bathymetry and sonar profiles A-A’ and B-B’. Coring location is represented by the black circle on the bathymetry map. The approximate coring location is depicted across the A-A’ transect with likely zonation indicated by the dashed lines.

66 ii.) Dating

One radiocarbon date was obtained for Blair Lake (Table 3.6). Sample

BL082011-C2-50 was obtained at 226 cm depth (length = 50 cm) and was identified as terrestrial grass remains. This sample yielded a calibrated age of 3,327 cal. yr. B.P.

(Stuiver and Reimer, 1993; Reimer et al., 2009).

Core Lab Sample Depth Material δ13C Age Calendar Calendar Number (cm) (14C yr BP) Age (2σ) Range (2σ) (cal. yr. BP) (cal. yr. BP) terrestrial BL-2 BL082011- 226 grass -14.9 3,147 +/- 86 3,327 3,082-3,572 C2-50 fragment

Table 3.8 Blair Lake radiocarbon ages. All radiocarbon analyses took place at the University of Arizona AMS Laboratory, Tuscon, Arizona. Calibrated ages are given as mean calendar years (Stuiver and Reimer, 1993; Reimer et al., 2009).

iii.) Lithostratigraphic Units (Figure 3.10 and 3.11)

Nine distinct lithostratigraphic units were visually identified in core BL-2. The basal unit, BL-Unit 1 (276-264 cm) is a dark, reddish-brown, clay (Hue 5 YR 4/3) and exhibits consistently low L.O.I. values (average 3.5% organic carbon content) and relatively high M.S. values (average 0.2 SI units). BL-Unit 1 is abruptly overlain by BL-

Unit 2 (264-188 cm), which exhibits many small oscillations between thicker red clay gyttja (Hue 5 YR 4/4) and fine very dark gray/black, organic rich layers (Hue 5 YR 3/1 or

2.5/1). BL-Unit 2 has similar trends in L.O.I. and M.S. values as BL-Unit 1 with average values of 3.7% and 0.2 SI units. From the upper portion of BL-Unit 2 to the lower portion sediments of BL-Unit 7, the L.O.I. and M.S. trends stay relatively stable; with L.O.I. values varying around a mean of 18% and M.S. values staying below 0.03 SI units.

Visually, there is another abrupt transition between BL-Unit 2 and BL-Unit 3 (188-

Figure 3.10 Blair Lake Lithostratigraphic Units (scale in cm).

178 cm). BL-Unit 3 is a dark gray, clay-rich gyttja (Hue 7.5 YR 4/1). From 178-137 cm,

BL-Unit 4 is a dark reddish brown layer (5 YR 3/3) that grades into a dark gray/brown gyttja (BL-Unit 5; 137-131 cm; Hue 5 YR 4/1). BL-Unit 5 then grades into an organic, dark reddish-brown gyttja (BL-Unit 6; 131-88 cm; Hue 5 YR 3/2). BL-Unit 7 (88-46 cm) is a black, organic-rich gyttja (Hue 5 YR 2.5/1) that transitions abruptly into a

68 reoccurrence of the dark gray, clay-rich BL-Unit 3 (46-42cm). This layer is then overlain by a dark reddish-gray clay unit (BL-Unit 8; 42-30 cm; Hue 5 YR 4/2). Another appearance of BL-Unit 3's dark gray, clay rich gyttja occurs above BL-Unit 8 from 30-27 cm. The upper most unit (BL-Unit 9; 27 cm-Top of Core) is a clastic, dark reddish brown gyttja (Hue 5 YR 3/4). From 46 cm to the top of the core (BL-Unit 3, BL-Unit 8, and BL-

Unit 9), L.O.I. and M.S. remain consistent with L.O.I. values decreasing abruptly and stabilizing with an average of 8.6% and M.S. values increasing gradually to an average of

0.07 SI units. c.) Chemostratigraphic Results (Figure 3.11)

i.) Paleosalinity (Chloride)

Chloride (Cl) values throughout BL-2 core are variable. From 276-46, Cl values appear cyclic with an average value of 3,852 ppm. There are several high values throughout this section with maximum values of 11,126 ppm, 7,222 ppm, 9,577 ppm, and

7,185 ppm at 211 cm, 147 cm, 130 cm, and 95 cm respectively. The upper most sediments (46-Top of Core) are more stable and much less variable with an average Cl value of 2,983 ppm.

ii.) Lead and Mercury Concentration

Pb values are low throughout much of the BL-2 core. From 276-46 cm, Pb values average 5.1 ppm. The upper most sediment (46 cm-Top of Core) exhibit values that increase rapidly to a maximum of 50 ppm.

Figure 3.11 Blair Lake stratigraphic and multi-proxy results. The record spans >3,327 calibrated years before present. 3 paleolimnological zones were identified.

II. Interpretation (Figure 3.11)

Modern Lake Characteristics

Limnological assessment indicates that Blair Lake is currently a eutrophic, freshwater lake. Blair Lake is the deepest of the three study lakes, however, due to high wind and wave (˃0.7 m) activity, water column mixing and the potential for sediment resuspension occurs often. As a consequence, short-lived stratification likely develops and the lake may be characterized as polymictic.

Zone 1: Nascent Lake Phase; 276-187 cm; 4,000-2,500 cal. yr. B.P.

BL Zone 1 represents a period of low productivity and higher clastic input with a predominantly terrestrial influence. The lithostratigraphic and chemostratigraphic values are comparable to JL Zone 1 and LL Zone 1. The basal, clay-rich sediment, low L.O.I., and high M.S. values represent the nascent stage of this lake. This interpretation is supported by other post-glacial limnological studies that have found initial lake sediments to be clay-rich and highly magnetic sediment (Rosenbaum and Reynolds, 2004). Chloride values are higher than typical freshwater environments (Gorham, 1958; Branchu and

Bergonzini, 2004). Higher background salinity readings for lakes within this region are possible due to their proximity to the ocean and the potential for sea spray transported by precipitation; Blair Lake is also the closest lake to the headwaters of the Chignecto Bay in this study (Gorham, 1958; Underwood, et al., 1981). Pb values are consistent and similar to the Pb values in JL Zone 1 and LL Zone 1, but relatively low in comparison to the rest of the Blair Lake core.

Zone 2: Open Marine/Lacustrine Phase; 187-42 cm; 2,500-600 cal. yr. B.P.

BL Zone 2 represents a period of increased productivity and salt water influence.

L.O.I. values increase abruptly, implying an increase in lake productivity. M.S. values decrease abruptly, indicating reduced clastic input. The average Cl value increases in this zone and is variable, likely indicating that Blair Lake was exposed to cyclical salt water inundation (Gorham, 1958; Branchu and Bergonzini, 2004). Several lakes in close proximity to Blair Lake also have cyclical salinity records due to their close proximity to the ocean (Gorham, 1958; Howell and Kerekes, 1982). Pb values remain similar to BL

Zone 1.

Zone 3: Lacustrine Phase; 42 cm-Top of Core; 600 cal. yr. B.P. to the present

BL Zone 3 represents a period of reduced salt water influence and productivity within a predominantly freshwater lake system. L.O.I. values decrease abruptly, while

M.S. values increase gradually. The Cl concentrations decrease and become less variable, indicating that salt water inundation either does not occur as often or does not occur at all due to the anthropogenic changes to the landscape (i.e. dyking; Wynn, 1979; Marlin et al., 2007). The Pb concentrations significantly increase throughout this zone.

Chapter 4: Discussion and Conclusions

4.1 Introduction

The Border Marshes are a complex macrotidal salt marsh system that has experienced significant post-glacial changes. Chalmers (1895), Trueman (1899), Ganong

(1903), and others have all investigated the post-glacial evolution of the Border Marshes.

In this study, paleolimnological records from the three study lakes indicate three unique evolutionary scenarios of both landscape and salt marsh evolution, with varying ages of initiation and zonation. Long Lake provides the oldest record (>10,000 cal. yr. B.P.) and contains evidence of four environmental zones. Jolicure Lake and Blair Lake records are both ~4,000 cal. yr. B.P long and indicate that both freshwater and salt water processes influenced lake sedimentation. This discussion will address 1) the age and evolution of the Border Marshes within the Isthmus of Chignecto based on paleolimnological evidence of environmental change and saltwater inundation, 2) the natural and anthropogenic sources of lead and mercury and their behaviour in the environment, and

3) potential management implications of this research.

4.2 Age and Evolution of the Border Marshes – Figure 4.1

A. 14,000-8,000 cal. yr. B.P. (Figure 4.2)

The Allerød period (~14,700-12,800 cal. yr. B.P.) was a time of increasing temperature and decreasing precipitation in Atlantic Canada, leading to the dissipation of regional glaciers. By 13,900 cal. yr. B.P., ice-free areas were colonized by shrubs, herbaceous plants, and trees (Mott and Stea, 1994). At this time, there is no recorded evidence that lakes had formed in the region. Long Lake could have been scoured and started to infill at this time; however, at the Allerød-Younger Dryas transition (~12,800

Figure 4.1 Landscape evolution (includes modified data from Amos and Zaitlin, 1985 and Lennox et al., 2010).

74 cal. yr. B.P.), climatic cooling resulted in ice re-advance by reactivating remnant ice or forming new ice caps, likely destroying any limnological record of lake initiation (Stea et al., 1998).

From 12,500 - 10,000 cal. yr. B.P., there were periods of glacial retreat and advance that were followed by regional ice retreat at which time the Maritime Provinces became mostly ice free (Stea et al., 1998; Fader, 2005). Long Lake has a basal age of

>10,355 cal. yr. B.P. and is the oldest of the three study lakes. The basal sediment in the

Long Lake core is a mixture of well sorted sand and gravel similar to shoreline sediment.

Rampton (1984) indicated that the Long Lake region contains morainal sediments consisting of mainly sandy till (>50% sand) that were deposited during late Wisconsinan ice retreat with some minor reworking by water. The similarity between the inorganic sediment at the bottom of the Long Lake core and the shoreline glacial sediment indicates that the complete post-glacial sediment record was recovered. L.O.I. values of <1% and high M.S. values indicate sediment at the base of the core was clastic, a common characteristic in newly exposed and deglaciated lake sites. Several studies have also shown that lake sediments from this period contain very low organic carbon content due to persistent ice and snow cover that limited plant cover and resulted in greater watershed erosion (King, 1994; Mott, 1994; Stea and Mott, 1998).

The transition from a colonizing shrub and herb assemblage to a boreal forest by

~10,500 cal. yr. B.P. likely resulted in increased soil stability and lower allochthonous clastic input (Railton, 1973). During this time, Long Lake was unproductive (LL-Zone 2;

Figure 3.6) with gradually increasing organic carbon content and high mineral/clastic content. By ~10,000 cal. yr. B.P., Long Lake was an established, moderately productive

Figure 4.2 Conceptual model of region at ~11,000 cal. yr. B.P.

76 lake (LL-Zone 3) with high organic carbon content and low clastic input; C/N values indicate a mainly terrestrial influence. These data indicate that during this lake phase, the regional terrestrial landscape was productive and forests were developing.

Significant early Holocene climatic events recognized elsewhere in Atlantic

Canada were not recognized in the Long Lake core. At ~8,800 and 8,200 cal. yr. B.P., there were disruptions in ocean thermohaline circulation that led to the slowing of deep water formation, a change in atmospheric circulation patterns, and regional cooling across

Atlantic Canada (Dyke and Prest, 1987; Hu et al., 1999; Spooner et al., 2002). Spooner et al. (2002) recognized a minerogenic oscillation at ~8.2 ka in a lake sediment record from northeastern Nova Scotia. However, the sustained allochthonous organic carbon input and low clastic input in Long Lake during this interval is consistent with the findings of

Lennox et al. (2010) from southwestern Nova Scotia that terrestrial vegetation did not react strongly to these cooling events. Therefore, the results from Long Lake indicate that landscape productivity occurred irrespective to the fluctuating regional climate.

After regional deglaciation 14,000 cal. yr. B.P., sea level fell rapidly as glacial rebound outpaced eustatic sea-level rise (Dalrymple et al., 1992; Figure 4.3). During this time, the locations now occupied by Jolicure Lake and Blair Lake were likely part of local fluvial drainage systems where water from uplands was transported to the receding coast line.

B. 8,000-4,500 cal. yr. B.P. – The Hypsithermal (Figure 4.4)

i. Landscape Evolution

From approximately 8,000-4,500 cal. yr. B.P., eastern North America was warmer and drier than present (Ruddiman, 2001). Lake levels throughout eastern North America

Figure 4.3 Approximate location of mean tide with respect to study lakes from deglaciation to ~300 cal. yr. B.P. Grey dashed line represents the upland boundary and orange dashed line represents the paleo-coastline at each time. A. ~11,000 cal. yr. B.P; post-glacial, sea level was slightly higher (~5 m) than. Long Lake was the only study lake in existence. The location of present day Jolicure Lake and Blair Lake are along fluvial drainage routes represented by the blue dashed arrows. B. ~7,000 cal. yr. B.P.; sea level was at its lowest (~-30 m). Long Lake was the only study lake present at this time. The location of present day Jolicure Lake and Blair Lake are along fluvial drainage routes represented by the blue dashed arrows. C. ~4,000 cal. yr. B.P.; sea level is slightly lower (~-5 m) than today. Salt marsh aggradation was occurring and all three study lakes were in existence. D. ~300 cal. yr. B.P.; the three study lakes and salt marsh environments are present

78 during this interval were lower than present and it was time of reduced standing water within the Atlantic Canada region (Harrison, 1989; Lennox et al., 2010). During this time, sustained high L.O.I. concentrations and low clastic input indicate that Long Lake was stable and productive, while the Jolicure Lake and Blair Lake sites were still likely located along fluvial drainage systems. Sea level was at its lowest at ~7,000 cal. yr. B.P., and salt marsh aggradation near the Jolicure Lake and Blair Lake sites had yet to occur.

At ~5,500 cal. yr. B.P., a decline in hemlock was recorded in Atlantic Canada and attributed to a regional drought (Lennox et al., 2010; Haas and McAndrews, 2000).

Warmer, drier climate and lower lake levels, along with established mature forests would have led to an increased incidence of fire. Increases in δ15N and metal concentrations (i.e. lead and mercury) in lake sediment cores can be the result of forest fires (Spencer et al.,

2003a; Spencer et al., 2003b; Kelly et al., 2006). Between ~5,500 and 4,500 cal. yr. B.P.,

δ15N values increase in the Long Lake sediment record and at ~5,000 cal. yr. B.P., there is also an increase in Hg and Pb. Studies have shown that increased mercury is typically a result of increased runoff from soil due to landscape instability as a result of forest fire

(Gresswell, 1999; Amirbahman et al., 2004). In addition, forest fires can result in enhanced lake productivity as they have the potential to produce a large nutrient release which can restructure the food web. A consequence would be elevated Hg concentrations in lake sediments (Gresswell, 1999; Carignan and Steedman, 2000; Spencer et al., 2003a;

Spencer et al., 2003b; Kelly et al., 2006). A significant input of wood at this time in the

Long Lake sediment core indicates vegetation and catchment disturbance. The wood could have been produced by forest die off associated with fire or disease (Davis, 1981;

Figure 4.4 Conceptual model of region at ~7,000 cal. yr. B.P.

Haas and McAndrews, 2000). Another possibility is either of these mechanisms coupled with large storms (i.e. hurricanes). ii. Salt water ingress (Figure 4.3)

Sea level had lowered over 60 m between 13,000 cal. yr. B.P. and 7,000 cal. yr.

B.P. to -25 m (Amos and Zaitlin, 1985). Sea level in the Border Marshes region reached a low stand at ~7,000 cal. yr. B.P. and tidal ranges at that time were mesotidal (2-4 m;

Amos and Zaitlin, 1985; Scott and Greenburg, 1983; Dalrymple et al., 1992). However, between 7,000-4,000 cal. yr. B.P., tidal amplitude increased rapidly to macrotidal range

(˃4 m; Scott and Greenburg, 1983; Dalrymple et al., 1992).

At ~8,000 and 6,000 cal. yr. B.P., high chloride values in the Long Lake core indicate that discrete salt water inundation events likely occurred and may be related to large tidal and/or storm events. The sampling resolution for this study is relatively coarse

(5 cm = ~150 yrs at Jolicure Lake; 5 cm = ~500 yrs at Long Lake; 5 cm = ~75 yrs at Blair

Lake) and as the tidal range and relative sea level continued to increase, Long Lake likely experienced other short-term salt water inundation events that were not resolved. Due to possible salt water influence, dryer climate, and lower lake levels during this time, freshwater lakes in this region may have become slightly saline (Figure 4.4).

Additionally, though relative sea level was rising during this period, the rate and magnitude are not well constrained. Pringle et al. (1957) reported drowned trees that were dated at 5,300 +/- 150 cal. yr. B.P. within the salt marshes next to Fort Lawrence,

Amherst, Nova Scotia and suggested that they were preserved by rapid salt marsh aggradation. This observation indicates that by ~5,300 cal. yr. B.P., sea level was rising and salt marsh aggradation was also beginning to occur.

C. 4,500-present – Post-Hypsithermal (Figure 4.5, 4.6, 4.7)

The Post Hypsithermal period in Maritime Canada was characterized by wet and cool conditions (Railton, 1973). Railton’s (1973) pollen record from Canoran Lake in southwestern Nova Scotia indicates an increase in quillwort, which is an initial colonizer in shallow water, indicating a rising water table. Between 4,500 and 3,800 cal. yr. B.P., the landscape experienced a period of crustal stability followed by a period of crustal depression and rapid submergence between 3,800-3,300 cal. yr. B.P. at 0.8m/century

(Harrison and Lyon, 1963). The increase in moisture in combination with land subsidence, increasing tidal amplitude, and the rising sea level contributed to the formation and development of Jolicure Lake and Blair Lake during this time (basal ages of >3,775 and > 3,327 cal. yr. B.P. respectively; Figure 4.3 and 4.5).

The sediment at the base of Jolicure Lake and Blair Lake is clay-rich with low organic carbon content and high clastic content. This sediment layer is characteristic of initial post-glacial sedimentation and nascent lake development (Rosenbaum and

Reynolds, 2004). Trueman (1899) suggested that the land depressions/valleys between structural ridges on the Isthmus of Chignecto would enlarge during times of crustal subsidence, thus providing an environment for Jolicure Lake and Blair Lake to form. In addition, the aggradation and encroachment of salt marsh inland in response to rising sea level and increasing tidal amplitude likely impeded lowland drainage systems (Figure 4.3 and 4.5). Tidal amplitude increased significantly between 7,000-4,000 cal. yr. B.P. and the Border Marshes are thought to have formed at the beginning of the crustal subsidence period with basal dates of <3,800 cal. yr. B.P. (Shaw et al., 2010; Scott and Greenburg,

1983). Shaw and Cemen (1999) indicated that a period of rapid salt marsh aggradation

Figure 4.5 Conceptual model of region at ~4,000 cal. yr. B.P.

83 occurred during the time the study lakes would have been forming (~3,000-2,600 cal. yr.

B.P.; Figure 4.5). Other researchers have suggested that the encroachment by migrating wetlands may have caused the damning of rivers and water bodies within the Isthmus of

Chignecto (Walker and Patterson, 1986). No environmental changes were resolved in the

Long Lake sediment core during this time, indicating that the climate and crustal influences did not significantly affect this already established lake and the proximal environment significantly.

Between ~3,400 and 3,250 cal. yr. B.P. there was a period of uplift at approximately 1.2 m/century, which was then followed by a renewed period of subsidence of ~0.3 m/century from 3,250-3000 cal. yr. B.P. (Harrison and Lyon, 1963).

In addition, from 3,000-2,600 cal. yr. B.P., rapid salt marsh aggradation took place (Shaw and Cemen, 1999). It is likely that during this period of increased moisture and rising water table, Jolicure Lake and Blair Lake basins were able to begin to hold fresh water and develop as freshwater lakes due to salt marsh aggradation damming drainage routes.

The formation of lakes in response to salt marsh aggradation is complex and not well understood. Low gradient reaches of fluvial systems may have been particularly susceptible to damming as the salt marsh aggraded and marine sediment was transferred landward. Several factors would influence the rate of vertical accretion and subsequent lake development, including changes in hydrology, rates of subsidence and eustatic sea level rise, and compaction of surface peats (DeLaune et al., 1992). In addition, once freshwater began ponding, the boundary between the freshwater and saltwater environments may have stabilized. The freshwater ecotones may have acted as a partial barrier to continued salt marsh inundation (Odum, 1988; Orson et al., 1992).

Jolicure Lake Zones 1 and 2 (4,500-2,000 cal. yr. B.P.) and Blair Lake Zone 1

(4,000-2,500 cal. yr. B.P.) have both been interpreted as freshwater aquatic deposits with increasing terrestrial organic carbon and decreasing clastic input, indicating that terrestrial flora close to each lake were likely thriving. At this time, Long Lake was also highly productive with L.O.I. values above 85% and low clastic input, indicating similar conditions to those at Jolicure Lake and Blair Lake. Salt marsh accretion is accomplished through a combination of mineral sediment accumulation and peat formation. These two factors can be interrelated since the influx of sediments also supplies nutrients for plant growth (DeLaune et al., 1992). Increased plant growth appears likely in the Border

Marshes region at this time and would have resulted in increased peat accumulation producing an enhanced ability to trap sediment. This process may have further reinforced the development and stability of the salt marsh dam at the outlets to Jolicure Lake and

Blair Lake.

Scott and Greenburg (1983) indicated that three other periods of rapid salt marsh aggradation occurred from 2,100-1,800 cal. yr. B.P., 1,300-900 cal. yr. B.P., and 400 cal. yr. to the present. Sea level curves for this time indicate an 11.5 m rise since ~3,800 cal. yr. B.P (Scott and Greenburg, 1983; Amos and Zaitlin, 1985; Figure 1.8). At this time, tidal amplitudes continued to increase (Amos and Zaitlin, 1985; Figure 1.8). The sediment records from Jolicure Lake and Blair Lake both indicate periods where the lakes likely experienced marine inundation (2,000-800 cal. yr. B.P. and 2,500-600 cal. yr. B.P. respectively). Trueman (1899) and MacNeill’s (1969) research provides a plausible explanation for potential salt water inundation into these two lake systems. These researchers suggest that salt water likely travelled far inland through the mobile and

85 constantly eroding and migrating drainage channels of the lakes during high tide cycles and storms. The Blair Lake sediment record has a variable chloride curve, indicating that salt water inundation into the lake system likely happened often. This scenario is plausible as Blair Lake is located very close to the modern marine limit (Figure 1.1).

Other nearby lakes (i.e. Layton’s Lake) at similar distances from the coast contain a distinct chemocline thought to have developed due to past salt water inundation (Howell and Kerekes, 1982). Jolicure Lake is located further from the coast, but has a lower gradient and no structural ridge to block inundation (Figure 1.1). Under these conditions, salt water ingress into the lake is also to be expected during high tidal cycles and storms.

Long Lake is isolated by a structural ridge and no salt water inundation events have been resolved in the core (Figure 1.1). The structural ridge and glacial outwash sediments inhibited saltwater ingress. Additionally, Long Lake has the highest surface elevation of all three study lakes (Figure 1.1). At this time, the salt marshes and coastal landscape were likely strongly influenced by high tidal range.

Post-contact change (i.e. dyking) is well recognized and documented within the wetlands of the Border Marshes (Figure 4.6 and 4.7). During this time, the lake sediment records from Jolicure Lake (Zone 4), Long Lake (Zone 4), and Blair Lake (Zone 3) indicate that these three lakes contain freshwater and are filling in with organic sediment resulting in lower L.O.I. values and increasing clastic input. Marine inundation during this time is reduced and eliminated, likely due to dyking by Acadians, which began during the early 1700s.

Figure 4.6 Conceptual model of region at ~300 cal. yr. B.P.

Figure 4.7 Conceptual model of modern day region.

4.3 Metals in the Environment

Pb and Hg concentrations were determined for all three sediment cores since these two metals are toxic to waterfowl and their mobility is poorly understood in salt marsh environments (Schwab and Daury, 1989; Boyle, 1977; O’Driscoll et al., 2005b; Evers et al., 2007). A quantification of baseline (pre-historic) concentrations of these metals is an important component to consider if the influence of the anthropogenic concentration is to be determined. In addition, both Pb and Hg can serve as proxies for a variety of landscape changes and Pb can be used as a time-stratigraphic marker due to the predictable anthropogenic contribution of lead at the top of sediment cores.

Through all pre-historic sediments, Pb concentrations correlate well with clastic input (r2=0.68 and 0.73; P values=0.04 and 0.03; Figure 4.8) and Hg concentrations correlate well with organic carbon concentration (r2=0.70 and 0.64; P values=0.04 and

0.05; Figure 4.9). Pb in water is known to bind to aquatic organic material (Aleksander-

Kwaterczak and Kostka, 2011). However, both natural lead deposition and accumulation in lake systems are commonly associated with the regional erosion of lead-bearing strata and the transportation of sediment to the site by glacial, fluvial, or other means. Inorganic suspended silt and clay in freshwater ecosystems have a strong tendency to absorb any dissolved lead (Denny et al., 1987). Therefore, lead movement and deposition can be commonly associated with the transport of particulate matter (Everard and Denny,

1985a). This explains the positive relationship between Pb concentrations and the clastic input proxy (magnetic susceptibility; r2=0.68 and 0.73; P values=0.04 and 0.03; Figure

4.8). The higher Pb concentrations within the pre-historic portions of the cores are likely associated with the erosion of local glacial sediments, whose input source was Pb-rich

A 18 16 14 12 10 8

Pb (ppm) Pb 6 r² = 0.68 4 P value = 0.04 2 0 0 0.05 0.1 0.15 Magnetic Susceptibility

B. 8 7 6

5 4 3 r² = 0.73 Pb (ppm) Pb 2 P value = 0.03 1 0 0.00 0.02 0.04 0.06 0.08 Magnetic Susceptibility

Figure 4.8 Linear regressions of magnetic susceptibility (clastic content) and lead for Jolicure Lake (A) and Long Lake (B). This data was graphed in Excel and r2 and P values were calculated using the R statistical program (Gentleman and Ihaka, 1997).

A 160 140

120

100 80 r² = 0.70 60 Hg (ppb) Hg P value = 0.04 40 20 0 0 5 10 15 20 25 30 Loss on Ignition (%)

B 200 180 160

140 r² = 0.64 120 P value = 0.05 100 80 Hg (ppb) Hg 60 40 20 0 0 20 40 60 80 100 Loss on Ignition (%)

Figure 4.9 Linear regressions of loss on ignition (organic carbon content) and mercury for Jolicure Lake (A) and Long Lake (B). This data was graphed in Excel and r2 and P values were calculated using the R statistical program (Gentleman and Ihaka, 1997).

91 bedrock (Foisy and Prichonnet, 1991). Regional ice flow for much of the Wisconsinan was from the north and northwest, and in this region produced thick, well-consolidated tills and morainal sediments (N.B. Dept. Nat. Res., 2002; Shaw et al., 2006). Likely sources for Pb in local till include the Mt. Whatley deposit (Pb, Ag, Cu, Zn) and the

Green Creek North deposit (Zn, Pb, Cu), both of which are located within late

Carboniferous strata, ˂60 km to the northwest of the study site (N.B. Dept. Nat. Res.,

2002).

Hg is known to readily complex with aquatic and terrestrial material. The dominant process in mercury retention with the lakes of the Isthmus of Chignecto is likely primary productivity (Poulain et al., 2004; Siciliano et al., 2002; Kirk et al., 2011).

This explains the relatively strong relationship between mercury concentrations and the organic carbon content (loss on ignition; r2=0.70 and 0.64; P values=0.04 and 0.05;

Figure 4.9). Models for Hg accumulation and remobilization in lake sediments indicate that the sediments contain a maximum initial concentration of Hg from natural deposition that decreased through time (Telmer et al. in O’Driscoll et al., 2005b). Additionally, no significant correlations were observed between Hg and chloride concentrations within the sediment cores (r2=0.35 and 0.10; P values=0.07 and 0.11; Figure 4.10). It is unlikely therefore, that mercury retention is related to salt water influx or aridity. This observation is in contrast to laboratory studies that suggest that additions of chloride may result in more oxidation of mercury or stabilization of Hg(II) in freshwater, and therefore, greater retention in lake sediments (Poulain et al., 2007; Qureshi et al., 2010). Due to the low water residence time in the study lake systems, salt water inundation events may have been diluted before extensive oxidation and retention of Hg in lake sediments took place.

A. 2500

2000 r² = 0.35 P value = 0.07

1500

1000

Cl (ppm) Cl 500

0 0 50 100 150 200 Hg (ppb)

B. 8000 7000 6000 r² = 0.10 5000 P value = 0.11 4000 3000

Cl (ppm) Cl 2000 1000 0 0.00 50.00 100.00 150.00 200.00 250.00 300.00

Hg (ppb)

Figure 4.10 Linear regressions of mercury and chloride for Jolicure Lake (A) and Long Lake (B). This data was graphed in Excel and r2 and P values were calculated using the R statistical program (Gentleman and Ihaka, 1997).

Continuous and prolonged salt water influence would likely be required for greater Hg retention. However, the low water residence time in these ecosystems and the lack of correlation between Hg and Cl concentrations in the sediment record indicate that chloride content cannot be used as a proxy for mercury retention.

Since Hg does not correlate with chloride in the sediment cores (r2=0.35 and 0.10;

P values=0.07 and 0.11; Figure 4.10), other mercury retention processes likely dominate, including biological reduction, lake productivity, and dissolved organic matter binding, all of which are supported by the previously discussed positive correlation between Hg concentrations and loss on ignition (r2=0.70 and 0.64; P values=0.04 and 0.05; Figure

4.9). In addition, better surrogates of salinity are required (i.e. C/N vs. δ13C biplot). In this research, the C/N vs. δ13C biplot was used to distinguish whether organic matter had a terrestrial, freshwater, or marine source. Jolicure Lake and Blair Lake both had periods influenced by salt water inundation (JL Zone 3, ~2,000-800 cal. yr. B.P. and BL Zone 2,

~2,500-600 cal. yr. B.P.). During these periods, chloride concentrations are variable in both lake sediment cores, indicating the freshwater lake systems were influenced by salt water inundation, but did not have a sustained marine influence.

In all three lake sediment cores, an increase in lead at the top of the core likely indicates the first appearance of anthropogenically produced metal to the site (Weiss et al., 2002; Suleyman, 2003; Terry, 2011). This increase in lead serves as an important time stratigraphic marker. During this time, all three lakes indicate a change to productive freshwater conditions with no salt water influence, which is a result, in part, of landscape alteration initiated by the Acadian settlers in the 17th century (Wynn, 1979). This may

94 also be a result of changing environmental conditions (i.e. fewer large storms) and/or increased aggradation limiting the landward movement of major salt water influx events.

An increase in mercury within the upper historic portions of the lake records is consistent with increasing anthropogenic releases from fossil fuel burning and global transport as observed in previous studies (Telmer in O’Driscoll et al., 2005b). However, it is likely that climate warming and an increase in primary productivity within the system are also important considerations in the historic increases in Hg concentrations (Outridge et al., 2007; Kirk et al., 2011). This observation is supported by the decrease in C/N ratios observed near the top of the lake sediment cores, implying increased autochthonous organic material input. In addition, recently reported decreases in Hg concentrations within lake organic sediment from a decline in the burning of coal were not observed due to the destruction of the top layer of sediment (0-10cm) as a result of the percussion coring technique.

4.4 Management Implications and Conclusions

The study lakes, as well as the other lakes and wetlands throughout the Border

Marsh region, have been influenced by both natural and anthropogenic disturbance.

However, each of the study lakes is unique and has developed under different conditions, providing multiple perspectives on the regional landscape evolution.

The Isthmus of Chignecto has been used by waterfowl and other organisms over the past ~10,000 years. However, the post-glacial Border Marsh environment was likely significantly different than today’s environment. After the last cooling event (8.2 ka) and into the Hypsithermal warm period, the landscape was drier and sea level was at its lowest, indicating less standing water. Scoured glacial basins, similar to Long Lake,

95 would have been the only location for freshwater to be stored for waterfowl use. At

~4,000 cal. yr. B.P., the landscape experienced significant changes due to rising sea level, increased tidal amplitude, continued land subsidence, salt marsh aggradation, and cooler, wetter climate conditions. During this time, Jolicure Lake, Blair Lake, and many other lakes in the Border Marsh region were likely formed as productive freshwater lakes due to salt marsh aggradation, with variable influence from salt water inundation.

Anthropogenically forced environmental change continued to have an effect on the lakes and wetlands of the Border Marshes. The most significant and iconic anthropogenic change has been the introduction of dykes in the 1700s and the alteration of salt marsh habitat. All three study lakes are restricted from marine influence by this alteration, operating as freshwater entities, and progressively infilling with both allochthonous and autochthonous organic sediment. However, controlled, man-made, freshwater impoundments are now becoming the favoured location for waterfowl resting and breeding grounds. These impoundments are actively managed to maintain optimum productivity levels and have increased the carrying capacity for waterfowl and marsh birds within the region (Maillet et al., 1999; MacKinnon, per. com. 2011). Due to this, the waterfowl usage of Jolicure Lake, Long Lake, and Blair Lake, along with the other freshwater lakes in the Border Marsh region, has been reduced (MacKinnon, per. com.

2011). This reduction in waterfowl usage in the natural lakes of the area is significant since animals and waterfowl both directly and indirectly affect primary productivity, and therefore, the overall functioning of a lake system (Vanni, 2002).

In addition, with projected climate warming, continued land subsidence, and rising sea level, the maintenance of the constructed dykes is becoming increasingly

96 expensive since they cannot self-adapt. Several options are possible in response to these projected changes. Dykes can be reinforced and/or raised to maintain the environment in its present state. Alternatively, dykes can be removed or allowed to degrade. If the latter option was chosen, this research provides a perspective on what would likely occur. This and other research has indicated that over the past ~4,000 cal. yr. B.P. as tidal amplitude and sea level increased and crustal subsidence continued, periods of rapid salt marsh aggradation took place. Jolicure Lake and Blair Lake were both formed from damming of drainage routes by migrating upland salt marsh. Salt marsh aggradation can result in rapid formation of freshwater ponds, which may be a consequence of dyke removal.

Finally, lead and mercury exist naturally in this environment. Pre-contact Pb and

Hg concentrations were present in significant concentrations in the three study lake cores, and not only provide insight on these metals’ behaviour, but also served as proxies for landscape change. Abrupt and short increases in both Pb and Hg at ~5,000 cal. yr. B.P. likely indicate a landscape disturbance (i.e. forest fire). Additionally, the strong positive correlations throughout the sediment cores between 1) lead and clastic input and 2) mercury and organic carbon, are important considerations if lakes and wetlands are to be developed or altered since these metals are toxic to waterfowl. In all three lake cores, decreasing L.O.I. values (carbon content) and increasing M.S. values (clastic input) correlate with increases in Pb concentration (Figures 4.8 and 4.9). Therefore, these systems are becoming better suited to accumulate both natural and anthropogenic lead since lead has a strong tendency to absorb to inorganic particulate suspended material

(Everard and Denny, 1985a; Denny et al., 1987).

Even though terrestrial organic carbon is decreasing in these environments

(decreasing L.O.I.), recent studies have suggested that primary productivity within a system due to climate warming may be an important component of increasing Hg concentrations (Outridge et al., 2007; Kirk et al., 2011). The climate is warming and the

C/N results for the study lakes show a decrease in C/N ratios, indicating increased autochthonous productivity (IPCC, 2007). Therefore, from a management perspective, as the climate continues to warm, the potential for mercury to accumulate in this region also increases.

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Appendices:

Appendix 1: Jolicure Lake Raw Data

A. Loss on Ignition

Depth Crucible Crucible and Wet Crucible and Crucible (cm) Mass (g) Sediment (g) Dry Sediment (g) and Ash (g) % LOI 152 17.02 20.84 19.91 19.8 3.81 147 17.28 22.92 21.48 21.3 4.29 143 20.99 24.82 23.96 23.84 4.04 138 21.92 25.9 24.91 24.77 4.68 133 17.49 20.28 19.59 19.48 5.24 133 18.97 21.86 21.05 20.94 5.29 128 21.59 24.64 23.07 22.91 10.81 123 16.21 18.25 17.24 17.15 8.74 118 17.66 20.84 18.93 18.76 13.39 113 20.7 22.81 21.46 21.34 15.79 113 19.41 22.63 20.18 20.06 15.58 108 21.39 24.82 22.29 22.08 23.33 103 20.68 22.74 21.19 21.06 25.49 98 18.96 23.48 21.88 21.75 4.45 93 18.97 23.95 22.21 22.08 4.01 93 17.24 21.11 20.5 20.37 3.99 88 17.88 20.4 18.82 18.73 9.57 83 19.28 21.67 20.4 20.33 6.25 78 17.24 21.56 19.44 19.33 5.00 73 17.99 20.54 19.34 19.27 5.19 73 22.25 25.36 23.63 23.56 5.07 68 19.83 22.97 21.63 21.54 5.00 63 17.39 20.14 19.12 19.05 4.05 58 22.83 28.01 26.04 25.91 4.05 54.5 19.41 22.85 21.6 21.53 3.20 54.5 20.99 24.21 23.15 23.08 3.24 50.5 17.66 22.87 20.9 20.77 4.01 45.5 22.25 25.17 24.12 24.05 3.74 40.5 30.49 34 32.69 32.6 4.09 36.5 17.28 22.46 20.16 19.98 6.25 36.5 21.38 24.39 24.22 24.04 6.34 30.5 17.67 20.48 18.59 18.44 16.30 25.5 20.99 23.82 21.75 21.61 18.42

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20.5 16.2 19.23 17.2 17.01 19.00 15.5 18.96 21.84 20.05 19.86 17.43 10.5 17.01 20.72 18.43 18.23 14.08 10.5 17.28 21.16 18.77 18.56 14.09 2.5 21.38 24.26 22.65 22.51 11.02

B. Magnetic Susceptibility

Depth Average 1 Average 2 Overall (cm) Average 152 0.125 0.135 0.130 147 0.163 0.165 0.164 143 0.061 0.063 0.062 136 0.077 0.079 0.078 131 0.096 0.094 0.095 126 0.053 0.052 0.053 123 0.041 0.041 0.041 118 0.03 0.03 0.030 113 0.02 0.02 0.020 106 0.018 0.016 0.017 103 0.014 0.018 0.016 98 0.07 0.071 0.071 91 0.05 0.05 0.050 88 0.031 0.031 0.031 82 0.049 0.05 0.050 78 0.052 0.056 0.054 73 0.08 0.083 0.082 68 0.143 0.145 0.144 63 0.12 0.12 0.120 58 0.104 0.11 0.107 54.5 0.076 0.084 0.080 49.5 0.113 0.116 0.115 45.5 0.133 0.133 0.133 40.5 0.071 0.072 0.072 36.5 0.048 0.049 0.049 30.5 0.02 0.02 0.020 25.5 0.02 0.02 0.020 20.5 0.022 0.024 0.023 15.5 0.028 0.029 0.029

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10.5 0.035 0.038 0.037 3.5 0.04 0.04 0.040

C. Carbon and Nitrogen Data

Depth CO2 N2 (cm) Amount Amplitude Amplitude δ13C δ15N %C %N C/N 151 15.375 0.375 0.387 -27.16 4.34 0.29 0.04 7.68 151 15.154 0.407 0.416 -27.13 4.56 0.33 0.04 7.82 145 15.137 0.244 0.343 -26.69 4.80 0.20 0.03 5.69 139 15.778 0.413 0.485 -26.59 5.81 0.32 0.05 6.71 135 15.625 0.505 0.515 -27.32 6.00 0.39 0.05 7.75 128 15.254 5.731 3.825 -27.89 4.32 5.02 0.37 13.40 123 15.406 3.788 2.752 -28.76 4.88 3.16 0.27 11.59 118 10.025 4.447 3.343 -28.10 3.99 5.77 0.51 11.39 108 10.160 7.678 5.758 -27.81 2.72 10.73 0.84 12.79 103 9.557 7.741 5.884 -27.13 3.90 11.53 0.91 12.70 98 10.255 0.700 0.666 -20.54 5.13 0.84 0.10 8.40 93 10.278 0.892 0.712 -19.79 4.98 1.07 0.11 10.00 88 9.891 6.114 2.891 -14.33 2.52 8.39 0.43 19.34 83 10.546 2.208 1.608 -19.96 3.45 2.61 0.23 11.24 78 6.660 0.905 0.789 -21.34 4.21 1.70 0.19 8.95 78 11.268 1.500 1.364 -21.33 4.02 1.60 0.18 8.89 68 10.313 0.859 0.881 -21.26 5.46 1.03 0.13 7.79 58 10.203 0.943 0.823 -20.39 5.08 1.13 0.12 9.18 48 9.965 0.744 0.685 -22.58 4.98 0.91 0.11 8.65 38 10.072 2.630 1.733 -27.47 3.76 3.27 0.26 12.48 34 9.896 5.095 3.025 -28.75 3.54 6.82 0.46 14.80 26 9.277 5.949 4.073 -29.46 3.34 8.72 0.67 13.08 16 9.861 5.779 3.639 -27.73 3.00 7.93 0.56 14.15 12 10.169 5.028 3.258 -28.92 3.14 6.55 0.49 13.49 6 10.421 3.413 2.295 -28.95 3.71 4.20 0.34 12.34

D. XRF Data

Depth Cl Pb Sample (cm) (ppm) (ppm) JL 2 151 1397 10 JL 2 run 2 151 1421 11 JL 14 139 1033 10

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JL 18 135 6879 7 JL 20 A 133 812 7 JL 20 B 133 899 7 JL 20 C1 133 914 6 JL 20 C2 133 887 7 JL 20 C3 133 980 6 JL 25 128 859 1 JL 30 123 776 1 JL 35 118 934 5 JL 40 A 113 1068 4 JL 40 B 113 1083 4 JL 40 C 113 931 4 JL 40 C2 113 1015 3 JL 40 C3 113 951 3 JL 45 108 1612 3 JL 50 103 739 2 JL 55 98 1359 8 JL 60 A 93 1741 10 JL 60 B 93 1655 9 JL 60 C1 93 1540 9 JL 60 C2 93 1370 10 JL 60 C3 93 1531 9 JL 65 88 2218 17 JL 70 83 2057 15 JL 75 78 2327 13 JL 80 A 73 2348 13 JL 80 B 73 2398 12 JL 80 C1 73 2364 14 JL 80 C2 73 2326 13 JL 80 C3 73 2461 14 JL 85 68 2494 15 JL 90 63 1475 14 JL 95 58 13166 9 JL 100 A 53 1532 11 JL 100 B 53 1539 11 JL 100 C1 53 1525 10 JL 100 C2 53 1520 10 JL 100 C3 53 1597 11 JL 105 48 7586 9 JL 112 41 1560 7 JL 115 38 1039 12

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JL 119 34 960 4 JL 122 31 848 6 JL 122 B 31 871 7 JL 122 C1 31 850 8 JL 122 C1 31 898 8 JL 122 C2 31 889 8 JL 122 C3 31 782 6 JL 127 26 803 5 JL 132 21 1021 10 JL 137 16 1140 10 JL 141 12 1216 11 JL 141 B 12 1101 5 JL 141 C1 12 1154 4 JL 141 C2 12 1147 5 JL 141 C3 12 999 3 JL 147 6 955 16

E. Mercury Analysis

Depth Sample Volume Area Mercury Concentration Name (cm) (mg) (HIGH1) (ng) (ppb) JL-3A2 150 102.3 7.83146 3.411 33.343 JL-3B2 150 116.1 9.89116 4.349 37.459 JL-3C2 150 110.6 8.68568 3.89 35.662 JL-10A2 143 101.3 7.43571 3.23 31.885 JL-10B2 143 103.2 6.91578 2.993 29.002 JL-10C 143 101.8 6.76036 2.922 28.703 JL-14A 139 102 8.05672 3.513 34.441 JL-14B 139 100.3 7.34307 3.188 31.785 JL-14C 139 103.4 7.47106 3.246 31.393 JL-20A 133 103.2 10.1569 4.46 43.654 JL-20B 133 105.4 10.4837 4.62 43.833 JL-20C 133 100.1 9.87377 4.342 43.377 JL-25A 128 109.3 25.7354 11.571 105.865 JL-25B 128 104.6 23.1877 10.991 103.812 JL-25C 128 100.9 22.8278 10.246 101.546 JL-33A 120 109 13.2543 5.882 53.963 JL-33B 120 103.4 12.8962 5.719 55.309 JL-33C 120 105.7 13.0236 5.759 54.763 JL-40A 113 103.4 20.5268 9.197 88.946

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JL-40B 113 104.2 21.2365 9.49 92.234 JL-40C 113 102.5 21.0153 9.42 91.902 JL-50A 103 100.8 19.4519 8.621 86.337 JL-50B 103 100.2 19.7797 8.857 88.393 JL-50C 103 101.9 19.1435 8.567 84.073 JL-60A 93 105.1 2.98962 1.132 11.118 JL-60B 93 106.2 2.90833 1.167 10.989 JL-60C 93 103.2 2.84947 1.14 11.047 JL-70A 83 103.8 3.97209 1.652 15.915 JL-70B 83 103.9 4.01987 1.893 16.661 JL-70C 83 103.8 3.58738 1.476 14.22 JL-80A 73 103.4 4.50547 1.895 18.327 JL-80B 73 100.7 4.63117 1.952 19.384 JL-80C 73 112.6 4.91839 2.083 18.499 JL-90A 63 100.8 2.9997 1.208 11.984 JL-90B 63 101.4 2.8076 1.121 11.055 JL-90C 63 111.3 3.14401 1.274 11.447 JL-100A 53 101 2.63071 1.04 10.297 JL-100B 53 119 2.99522 1.206 10.134 JL-100C 53 102.2 3.00951 1.213 11.869 JL-112A 41 99.9 3.54899 1.459 14.605 JL-112B 41 109.4 3.76696 1.558 14.241 JL-112C 41 102.8 3.95476 1.599 14.051 JL-118A 35 100.3 5.37104 2.253 32.463 JL-118B 35 100.1 5.02387 1.998 30.654 JL-118C 35 103.3 8.13989 3.515 34.027 JL-122A 31 99.9 22.7718 10.185 101.952 JL-122B 31 101 22.3487 9.96 99.3 JL-122C 31 100 21.9058 9.79 97.9 JL-132A 21 103.1 28.6292 12.855 124.685 JL-132B 21 102.6 28.5962 12.836 124.989 JL-132C 21 102 28.5393 12.814 125.627 JL-141A 12 102.9 31.5702 14.195 137.949 JL-141B 12 102.1 30.1952 13.568 132.889 JL-141C 12 103.2 30.6859 13.894 135.699 JL-146A 7 102.8 35.5415 16.005 151.691 JL-146B 7 100.1 31.7536 14.279 148.647 JL-146C 7 101.6 33.6497 15.492 150.228

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Appendix 2: Long Lake Raw Data

A. Loss on Ignition

Depth Crucible Crucible and Crucible and Dry Crucible % LOI (cm) Mass (g) Wet Sediment (g) Sediment (g) and Ash (g) 126 21.59 25.69 25 24.98 0.59 118 20.71 24.08 23.33 23.31 0.76 110 17.49 22.37 21.14 21.12 0.55 110 19.91 23.44 23.38 23.36 0.58 103 20.69 22.57 20.95 20.8 57.69 98 21.92 24.99 22.18 21.98 76.92 93 17.67 20.16 17.92 17.69 92.00 93 22.25 24.88 22.53 22.27 92.86 88 22.83 23.54 22.87 22.83 100.00 83 18.98 20.42 19.11 18.98 100.00 78 19.28 20.56 19.39 19.28 100.00 73 17.39 19.39 17.59 17.4 95.00 73 19.83 22.11 20.06 19.84 95.65 68 17.99 19.95 18.18 17.99 100.00 64 17.24 19.22 17.45 17.25 95.24 58 19.41 22.14 19.86 19.47 86.67 53 22.25 24.16 22.62 22.31 83.78 53 21.92 24.14 22.32 21.98 85.00 47 19.83 21 20.06 19.88 81.20 43 17.88 19.56 18.24 17.93 86.11 31 30.49 32.57 30.77 30.51 92.86 31 17.66 20.21 17.99 17.68 93.94 27 17.49 20.43 17.85 17.52 91.67 21 21 22.47 21.19 21.01 94.74 16 18.97 21.46 19.33 19 91.67 10 17.28 19.11 17.51 17.31 86.96 10 18.97 20.44 19.22 19 88.00 5 21.92 25.11 23.12 22.91 17.50 1 17.66 19.94 18.53 18.38 17.24

121

B. Magnetic Susceptibility

Depth Average 1 Average 2 Overall (cm) Average 126 0.046 0.049 0.048 118 0.035 0.039 0.037 110 0.027 0.03 0.028 103 0.021 0.022 0.022 98 0.016 0.016 0.016 93 0.018 0.023 0.020 88 0.021 0.023 0.022 83 0.023 0.021 0.022 78 0.013 0.014 0.014 73 0.008 0.01 0.009 68 0.014 0.013 0.014 64 0.012 0.01 0.011 58 0.012 0.014 0.013 53 0.017 0.017 0.017 46 0.012 0.01 0.011 43 0.01 0.01 0.010 33 0.016 0.016 0.016 27 0.019 0.018 0.019 21 0.017 0.017 0.017 10 0.016 0.017 0.017 5 0.02 0.02 0.020 1 0.025 0.02 0.030

C. Carbon and Nitrogen Data

Depth CO2 N2 (cm) Amount Amplitude Amplitude δ13C δ15N %C %N C/N 130 99.391 0.206 0.544 -26.75 2.79 0.03 0.01 2.83 121 101.003 0.136 0.359 -28.06 3.27 0.02 0.01 2.87 108 100.645 0.562 0.606 -29.33 2.92 0.07 0.01 6.97 103 3.174 6.393 3.774 -27.46 0.06 27.04 1.75 15.45 93 3.474 10.818 7.115 -29.35 0.42 48.79 2.95 16.52 83 3.080 10.098 3.496 -27.51 0.05 50.24 1.66 30.20 73 3.052 10.253 4.356 -27.01 0.02 51.61 2.10 24.56 63 3.225 10.466 4.633 -27.36 0.16 50.27 2.06 24.39 53 3.130 9.325 3.171 -27.03 2.28 44.35 1.47 30.17

122

48 3.234 8.930 3.697 -26.56 4.60 40.52 1.67 24.30 43 3.277 9.737 3.705 -26.29 1.88 44.90 1.65 27.17 26 3.606 10.600 4.460 -27.29 1.04 45.83 1.81 25.36 21 3.253 9.791 4.318 -25.96 0.39 45.87 1.98 23.21 16 3.284 9.396 4.445 -27.34 0.62 42.85 2.00 21.42 11 3.498 9.534 4.042 -27.23 0.84 41.05 1.71 23.97 6 3.154 2.138 1.105 -28.48 1.67 8.29 0.53 15.63 6 3.365 2.337 1.180 -28.75 1.88 8.61 0.54 16.04 1 3.596 2.360 1.248 -28.47 1.70 8.07 0.53 15.35

D. XRF Data

Depth Cl Pb Sample (cm) (ppm) (ppm) LL 3 130 170 4 LL 12 121 123 4 LL 25 A 108 85 5 LL 25 B 108 99 5 LL 25 C1 108 87 6 LL 25 C2 108 76 5 LL 25 C3 108 85 5 LL 30 103 2109 2 LL 35 98 481 2 LL 40 A 93 4277 2 LL 40 B 93 3844 2 LL 40 C1 93 4696 2 LL 40 C2 93 4720 2 LL 40 C3 93 4704 2 LL 45 88 2911 2 LL 50 83 30924 2 LL 55 78 2658 2 LL 60 A 73 6233 2 LL 60 B 73 7064 2 LL 60 C1 73 6123 2 LL 60 C2 73 5905 2 LL 60 C3 73 5807 2 LL 65 68 20165 2 LL 70 63 7153 2 LL 75 58 146 2

123

LL 80 C1 53 1102 4 LL 80 C2 53 1227 4 LL 80 C3 53 1091 4 LL 85 48 897 8 LL 90 43 367 0 LL 95 38 235 0 LL 99 A 34 77 0 LL 99 B 34 89 0 LL 99 C 34 80 0 LL 99 C2 34 82 0 LL 99 C3 34 75 0 LL 107 26 841 0 LL 112 21 166 0 LL 117 16 563 0 LL 122 A 11 2354 0 LL 122 B 11 1079 2 LL 122 C1 11 1070 1 LL 122 C2 11 1057 2 LL 122 C3 11 995 2 LL 127 6 639 7 LL 132 1 878 8

E. Mercury Analysis

Depth Sample Volume Area Mercury Concentration Name (cm) (mg) (HIGH1) (ng) (ppb) LL-3A 130 100.9 0.865647 0.2 1.982 LL-3B 130 102.1 0.696257 0.123 1.205 LL-3C 130 102.3 0.873716 0.204 1.994 LL-25A 108 104.9 0.702945 0.126 1.201 LL-25B 108 100.5 0.753133 0.149 1.483 LL-25C 108 100.1 0.738512 0.136 1.233 LL-35A 98 106.8 15.10208 6.689 62.631 LL-35B 98 101.3 15.31585 6.725 64.274 LL-35C 98 104.4 15.07361 6.676 63.946 LL-40A 93 101 12.73937 5.612 55.564 LL-40B 93 105.6 13.66587 5.989 57.992 LL-40C 93 104.6 13.88915 6.136 58.662 LL-45A 88 100.1 6.606876 2.547 25.445

124

LL-45B 88 112.6 6.725903 2.602 23.108 LL-45C 88 97.6 6.746827 2.611 26.752 LL-55A 78 106.2 4.315618 2.597 26.986 LL-55B 78 112.4 7.82348 3.102 27.598 LL-55C 78 99.5 6.984566 2.72 27.337 LL-60A 73 104.9 11.36485 4.597 42.252 LL-60B 73 112.9 11.00543 4.552 40.319 LL-60C 73 113.6 11.88415 4.953 43.6 LL-65A 68 103.7 16.55982 6.981 65.679 LL-65B 68 106.5 17.08308 7.323 68.761 LL-65C 68 113.2 15.99369 6.826 64.3 LL-75A 58 106.7 71.52946 31.238 280.337 LL-75B 58 111.6 52.07037 23.27 238.513 LL-75C 58 111.9 64.60725 28.984 259.017 LL-80A 53 100.4 198.3381 89.939 895.807 LL-80B 53 109.7 185.9217 84.28 868.277 LL-80C 53 106.3 224.8613 102.029 859.821 LL-95A 38 101.7 32.99031 14.573 143.294 LL-95B 38 102.1 32.37456 14.293 139.99 LL-95C 38 106.5 33.25943 14.696 137.991 LL-99A 34 103.1 32.72165 14.325 140.036 LL-99B 34 103.5 30.59672 13.482 130.261 LL-99C 34 101.5 31.44018 13.867 136.621 LL-117A 16 108.3 42.66146 18.981 175.263 LL-117B 16 102.8 39.03588 17.866 173.921 LL-117C 16 103.8 41.9102 18.639 179.566 LL-122A 11 105.3 39.01694 17.32 164.482 LL-122B 11 100.6 30.68257 15.562 151.969 LL-122C 11 101.7 36.2942 16.079 158.102 LL-131A 2 101.1 16.11791 6.883 68.081 LL-131B 2 102.4 15.54916 6.623 64.678 LL-131C 2 103.3 16.95298 7.263 70.31

125

Appendix 3: Blair Lake Data

A. Loss on Ignition

Depth Crucible Crucible and Wet Crucible and Dry Crucible (cm) Mass (g) Sediment (g) Sediment (g) and Ash (g) % LOI 273 20.71 25.57 23.96 23.85 3.38 269 17.02 20.16 19.11 19.03 3.83 263 21.59 26.21 24.75 24.66 2.85 257 16.21 20.24 19.11 19.05 2.07 257 18.97 22.98 21.83 21.77 2.10 251 20.69 25.05 23.67 23.59 2.68 246 21.38 25.93 24.41 24.32 2.97 241 17.39 21.98 21.83 20.75 24.32 236 19.4 22.84 21.77 21.69 3.38 236 30.48 34.02 32.87 32.79 3.35 231 22.24 25.54 24.62 24.55 2.94 226 19.83 24.93 23.39 23.29 2.81 221 22.82 26.08 25.18 25.13 2.12 216 17.88 22.8 21.32 21.22 2.91 216 19.83 24.31 23.23 23.13 2.94 211 19.27 23.55 22.37 22.31 1.94 206 18.97 23.49 22.1 22.02 2.56 200 17.98 21.93 20.71 20.63 2.93 196 17.65 21.21 20.24 20.18 2.32 196 16.21 19.56 18.76 18.7 2.35 192 17.23 22.05 20.5 20.39 3.36 189 30.48 35.71 34.22 34.15 1.87 186 20.7 22.87 21.68 21.58 10.20 184 17.01 19.7 18.02 17.9 11.88 180 20.99 24.66 22.25 22.06 15.08 177 21.59 24.48 22.93 22.81 8.96 177 20.7 24.31 22.08 21.96 8.70 172 18.96 22.26 20.08 19.92 14.29 167 21.39 24.31 22.48 22.32 14.68 162 17.27 21.14 18.74 18.52 14.97 157 17.48 20.96 18.82 18.63 14.18 157 20.69 23.87 21.99 21.81 13.85 152 21.92 26.59 23.7 23.46 13.48 147 17.66 20.97 18.66 18.5 16.00

126

142 20.69 23.55 21.41 21.27 19.44 138 16.21 19.76 17.31 17.14 15.45 138 19.41 22.99 20.55 20.37 15.79 134 17.88 21.53 19.46 19.27 12.03 130 20.69 23.97 21.9 21.72 14.88 127 17.28 19.62 17.99 17.87 16.90 122 18.96 22.55 20.17 19.99 14.88 117 18.98 22.08 20.17 20.01 13.45 117 17.49 20.64 18.62 18.47 13.27 112 17.4 20.33 18.51 18.35 14.41 107 23.83 27.49 24.57 24.31 35.14 101 17.66 21.21 18.91 18.71 16.00 97 19.41 23.23 20.81 20.61 14.29 97 22.24 26.16 23.68 23.47 14.58 92 16.21 19.82 17.55 17.36 14.18 87 20.7 25.14 22.3 22.06 15.00 82 21.39 24.21 22.34 22.19 15.79 77 17.49 20.18 18.33 18.2 15.48 77 19.27 21.99 20.16 20.02 15.73 72 21.58 24.37 22.16 22.01 25.86 67 19.84 22.61 20.51 20.35 23.88 62 22.24 25.91 23.16 22.93 25.00 57 17.23 20.78 18.23 18.01 22.00 57 17.66 21.03 18.77 18.54 20.72 52 17.99 21.63 19.02 18.79 22.33 47 20.99 24.2 21.82 21.63 22.89 43.5 21.91 26.2 24.06 23.9 7.44 40 17.01 22.15 19.58 19.38 7.78 34 17.66 22.86 20.39 20.21 6.59 34 19.4 24.38 22.01 21.84 6.51 28 19.27 24.27 21.56 21.37 8.30 25 30.48 33.59 32 31.86 9.21 22 21.38 24.42 22.99 22.84 9.32 17 17.27 20.9 19.23 19.05 9.18 17 21.58 24.67 23.52 23.34 9.28 12 20.7 24.58 22.71 22.53 8.96 7 17.65 22.12 19.95 19.74 9.13 2 19.4 22.63 21.06 20.89 10.24 2 17.01 20.66 18.64 18.47 10.43

127

B. Magnetic Susceptibility

Depth Overall (cm) Average 1 Average 2 Average 269 0.204 0.22 0.212 263 0.213 0.217 0.215 257 0.193 0.211 0.205 251 0.212 0.217 0.215 246 0.183 0.18 0.182 241 0.217 0.215 0.216 236 0.157 0.163 0.160 231 0.182 0.186 0.184 226 0.128 0.128 0.128 221 0.177 0.176 0.177 216 0.159 0.16 0.159 211 0.204 0.205 0.205 206 0.222 0.224 0.223 200 0.203 0.204 0.204 194 0.209 0.206 0.207 190 0.21 0.208 0.209 185 0.071 0.07 0.071 180 0.03 0.03 0.030 177 0.038 0.04 0.039 172 0.03 0.03 0.030 167 0.024 0.028 0.026 162 0.024 0.026 0.025 157 0.027 0.029 0.028 152 0.025 0.022 0.024 147 0.019 0.02 0.020 142 0.026 0.028 0.027 138 0.018 0.02 0.019 134 0.03 0.03 0.030 130 0.03 0.03 0.030 127 0.03 0.03 0.030 122 0.025 0.028 0.027 117 0.02 0.019 0.020 112 0.025 0.023 0.024 107 0.027 0.025 0.026 101 0.025 0.023 0.024 97 0.024 0.023 0.023

128

92 0.03 0.03 0.030 87 0.028 0.028 0.028 82 0.026 0.028 0.027 77 0.021 0.021 0.021 72 0.017 0.018 0.018 67 0.019 0.02 0.020 62 0.02 0.02 0.020 57 0.024 0.027 0.026 52 0.02 0.02 0.020 47 0.027 0.028 0.028 43.5 0.034 0.036 0.035 40 0.04 0.04 0.040 34 0.03 0.029 0.030 28 0.032 0.033 0.033 25 0.038 0.037 0.038 22 0.061 0.062 0.062 17 0.076 0.079 0.077 12 0.073 0.073 0.073 7 0.069 0.07 0.070 2 0.06 0.061 0.061

C. XRF Data

Depth Cl Pb Sample (cm) (ppm) (ppm) BL 3 273 3469 6 BL 8 268 6141 10 BL 15 261 1563 8 BL 20 A 256 1698 4 BL 20 B 256 1706 5 BL 20 C1 256 1666 6 BL 20 C2 256 1776 5 BL 20 C3 256 1727 4 BL 25 251 1825 7 BL 30 246 1899 8 BL 35 241 1173 4 BL 40 A 236 2588 7 BL 40 B 236 2239 8 BL 40 C1 236 2480 8 BL 40 C2 236 2571 8

129

BL 40 C3 236 2774 7 BL 45 231 2030 7 BL 53 223 1000 4 BL 55 221 1791 5 BL 60 A 216 2065 5 BL 60 B 216 2827 8 BL 60 C1 216 1600 8 BL 60 C2 216 1526 8 BL 60 C3 216 1546 7 BL 65 211 11126 7 BL 70 206 1749 8 BL 77 199 929 7 BL 86 190 1005 6 BL 91 A 185 4122 7 BL 91 B1 185 4102 6 BL 91 B2 185 4108 5 BL 91 B3 185 4307 7 BL 96 180 3909 3 BL 102 174 2071 9 BL 106 170 6886 5 BL 114 A 162 4013 3 BL 114 B1 162 4159 4 BL 114 B2 162 4086 3 BL 114 B3 162 3895 2 BL 119 157 2912 6 BL 124 152 3733 5 BL 129 147 7222 2 BL 137 A 139 4628 3 BL 137 B1 139 4749 4 BL 137 B2 139 4667 4 BL 137 B3 139 4599 5 BL 142 134 3273 6 BL 146 130 9577 7 BL 154 122 4328 6 BL 159 A 117 5476 4 BL 159 B1 117 5411 3 BL 159 B2 117 5375 5 BL 159 B3 117 5449 4 BL 164 112 5476 4 BL 170 106 4455 5 BL 176 100 2817 3

130

BL 181 A 95 7164 5 BL 181 B1 95 7185 4 BL 181 B2 95 6907 5 BL 181 B3 95 7126 5 BL 189 87 1915 3 BL 194 82 1825 2 BL 199 77 3115 7 BL 204 A 72 5201 4 BL 204 B1 72 5665 4 BL 204 B2 72 5921 5 BL 204 B3 72 5760 4 BL 209 67 2993 5 BL 214 62 4421 3 BL 219 57 2729 3 BL 224 A 52 4867 3 BL 224 B 52 4983 2 BL 224 A2 52 5745 2 BL 224 A3 52 5867 2 BL 229 47 3199 1 BL 233 43 2826 9 BL 237 A1 39 3589 8 BL 237 A2 39 3483 8 BL 237 A3 39 3611 7 BL 237 B 39 3755 8 BL 244 32 3617 6 BL 248 28 3467 12 BL 254 A1 22 2719 27 BL 254 A2 22 2732 27 BL 254 A3 22 2719 29 BL 254 B 22 2754 27 BL 259 17 3098 27 BL 264 12 3743 45 BL 269 7 3637 44 BL 274 A 2 2032 50 BL 274 B1 2 2046 49 BL 274 B2 2 1973 46 BL 274 B3 2 1901 46

131