Permafrost in Canada's Subarctic Region of Northern Ontario

Home , Kenora, Kenora District, Northern Quebec, Peawanuck, Subarctic

Permafrost in Canada’s Subarctic Region of Northern

Ontario.

Andrew Tam

A thesis submitted in conformity with the requirements

for the degree of Masters of Science

Graduate Department of Geography

University of Toronto

An investigation of permafrost (permanently frozen soil) was conducted in

Canada‟s subarctic region of Northern Ontario. Environmental baseline conditions and permafrost states were estimated using seasonal freezing and thawing energies based on observed climate data and the Stefan equation. Field studies provided measurements of the active layer depths and validated the permafrost states; laboratory studies of the soil samples provided characterization for organic materials that have high affinity for soil moisture. Palsas (unique dome-like formations) were observed to have enhanced permafrost cores beneath a thermal insulating organic layer. With climate change, results suggest the possibility of shifts from the classification of continuous to discontinuous permafrost states in areas lacking the presence of organic materials that can have environmental and ecological impacts. Northern infrastructures may become destabilized with the degradation of permafrost while palsas may become lone permafrost refuges for biodiversity that depend on cooler ecosystems, such as polar bears.

ii Acknowledgments

Foremost, I would like express sincere gratitude to my supervisor, Prof. William Gough, for his valuable assistance, guidance, professional knowledge, and most of all, for his patience. I thank him for giving me the opportunity to grow as a student, to participate in pursing a Masters degree, and to take responsibility in encompassing a research of this scope. I would like to recognize the assistance of Martyn Obbard and his personnel at the Ontario Ministry of Natural Resources for this unique opportunity to study permafrost in all of Northern Ontario. I would like to acknowledge and express my gratitude to my fellow colleagues Muaz Nasir and Joyce Zhang for their continuing and unwavering moral and academic support and, in many instances, for providing me with reassurances throughout my years at the University of Toronto at Scarborough. I would like to recognize the contributions of Slawomir Kowal for his time in preparing temperature data and for his assistance in the laboratory. I would like to give special thanks to S. Das, J.W. Cowan, T.R. Beeby and A. Sarwari for their auxiliary support in conquering the battle of proofreading my thesis. I would like to extend special thanks to my parents for all their love, help and support in my endeavours. I would like to show appreciation to my brother, Charles Tam, and my sister-in-law, Angela, for all their continuing encouragements, support and faith in my abilities. Finally, I would like to thank all my friends and supporters in Trenton and Toronto whom continue to cheer me on in my life. Funding from the Department of Geography at the University of Toronto supported this research and funding by the Ontario Ministry of Natural Resources supported the fieldwork.

iii Table of Contents

Abstract …………………………………………………………………… ii Acknowledgements .……...…………………………………………………… iii Table of Contents …………………………………………………………… iv List of Figures …………………………………………………………………… vi List of Tables …………………………………………………………………… vii

CHAPTER 1: Introduction …………………………………………………… 1 1.1 Project Description …………………………………………… 1 1.2 Aim, Objectives and Hypotheses …………………………………… 3

CHAPTER 2: Literature Review …………………………………………… 5 2.1 Introduction …………………………………………………… 5 2.2 Surface Vegetation and Active Layer …………………………… 6 2.3 Permafrost …………………………………………………… 8 2.3.1 Defining Permafrost …………………………………… 8 2.3.2 Formation and Degradation Processes …………………… 10 2.3.3 Soil Moisture Content and Thermal Conductivity …… 12 2.3.4 Stefan Depth and Permafrost Table …………………… 15 2.3.5 „Thermal Offset‟ …………………………………… 16 2.4 Palsa …………………………………………………………… 17 2.4.1 Defining Palsa …………………………………………… 17 2.4.2 Physical Properties of Palsas …………………………… 18 2.4.3 “Palsa Lifting” …………………………………………… 20 2.4.4 The Palsa Cycle …………………………………………… 20 2.5 Soil Temperatures and Net Radiation …………………………… 22 2.6 Ground Heat Flux …………………………………………… 23 2.7 Geophysical Detection of Permafrost …………………………… 24 2.7.1 Ground Temperature Borehole Logging …………… 25 2.8 Literature Summary …………………………………………… 26

CHAPTER 3: Experimental Design and Methodology …………………… 30 3.1 Location and Study Site Descriptions …………………………… 31 3.1.1 Biogeography …………………………………………… 32 3.1.2 Climate Data and Weather Stations …………………… 34 3.2 Field Experimental Design …………………………………… 35 3.2.1 Soil Temperatures and Thermistor Probes …………… 35 3.2.2 Point-scale Geophysical Sampling …………………… 35 3.2.3 Sample Labelling and Identification …………………… 38 3.2.4 Field Soil Characterization …………………………… 39 3.3 Laboratory Analytical Methodology …………………………… 39 3.3.1 List of Materials …………………………………… 39 3.3.2 Laboratory Soil Characterization …………………… 40 3.3.3 Gravimetric Soil Moisture Content …………………… 41

iv 3.3.4 Soil Acidity, Average pH Value …………………… 43 3.3.5 Soil Moisture Content Loss Test …………………… 43 3.4 Stefan Depth and Permafrost Table Calculations …………………… 45 3.5 Thawing and Freezing Degree-Days Calculations …………… 46 3.6 Geographical Information Systems …………………………… 47

CHAPTER 4: Results …………………………………………………… 48 4.1 Climate and Environmental Data …………………………………… 48 4.2 Soil Characterization (2007-2008) …………………………… 49 4.3 Laboratory Analysis Results (2007-2008) …………………… 58 4.3.1 Soil Moisture Content and Soil Acidity …………………… 58 4.3.2 Measured Depths to Permafrost …………………………… 61 4.4 Freezing and Thawing Degree-Days (1989-2007) …………… 64 4.4.1 Results from 1989 to 2002 …………………………… 64 4.4.2 Results from 2004 to 2007 …………………………… 66 4.5 Stefan Depth and Permafrost Table Results (1989-2007) …… 68 4.5.1 Porous Sandy Soils (1989 to 2007) …………………… 70 4.5.2 Non Porous Sandy Soils (1989 to 2007) …………… 72 4.5.3 Clay Soils (1989 to 2007) …………………………… 74 4.5.4 Peat and Organic Materials (1989 to 2007) …………… 77 4.6 Soil Moisture Content Loss Test (2008) …………………………… 81

CHAPTER 5: Discussion …………………………………………………… 82 5.1 Soil Characterization …………………………………………… 82 5.2 Freezing and Thawing Degree-Days …………………………… 85 5.3 Stefan Depth and Permafrost Table …………………………… 86 5.4 Permafrost Presence …………………………………………… 89 5.5 Palsa Presence …………………………………………………… 93 5.6 Addressing Research Question 1 …………………………………… 94 5.7 Addressing Research Question 2 …………………………………… 97 5.8 Sources of Error and Uncertainties …………………………… 98 5.9 Potential Research Impacts on Society …………………………… 101

CHAPTER 6: Conclusion …………………………………………………… 103 6.1 Permafrost …………………………………………………… 103 6.2 Palsas …………………………………………………………… 105 6.3 Recommendations for Further Research …………………………… 106

References …………………………………………………………………… 108 APPENDIX – Additional Figures …………………………………………… 115

v List of Figures

Figure 1 – “Baby” Palsa in Northern Ontario, August 2007 …………………… 18 Figure 2 – Location of settlements, weather stations and rivers in Northern Ontario …………………………………………………… 30 Figure 3 – Terrestrial Ecozones for the Hudson Bay Lowlands by Natural Resources Canada (Natural Resources Canada, 2007) …………… 32 Figure 4 – Forested Ecozones for the Hudson Bay Lowlands by Natural Resources Canada (Natural Resources Canada, 2003) …………… 33 Figure 5 – Sampling Sites located in Northern Ontario Hudson Bay divided by Three Quadrants from both 2007 and 2008 Soil Sampling Campaigns …………………………………………………… 36 Figure 6 – Sampling Sites located in Northern Ontario - Hudson Bay for 2007 divided by Three Quadrants …………………………………………… 37 Figure 7 – Sampling Sites located in Northern Ontario - Hudson Bay for 2008 divided by Three Quadrants …………………………………………… 38 Figure 8 – Labeled sample bag with associated tin foil tray container …… 40 Figure 9 – Analysis of soil sample D5a …………………………………… 41 Figure 10 – Subsurface stratigraphy classification of Northern Ontario and Hudson Bay by Natural Resources Canada (Natural Resources Canada, 2006) …………………………………… 48 Figure 11 – Results: Freezing and thawing degree-days for Peawanuck, Ontario, from 1989-2002 …………………………………………… 64 Figure 12 – Results: Freezing and thawing degree-days for Peawanuck, Ontario, from 2004-2007 …………………………………………… 66 Figure 13 – Thermal conductivity to water content for fine-grained soils, both frozen and thawed soils (Nixon & McRoberts, 1973) …………… 69 Figure 14 – Thermal Offset for Sand (Porosity >0.33) Compositions 1989-2007 …………………………………………… 70 Figure 15 – Thermal Offset for Sand (Porosity <0.33) Compositions 1989-2007 …………………………………………… 72 Figure 16 – Thermal offset for Clay Compositions 1989-2007 …………… 75 Figure 17 – Thermal Offset for Peat Compositions 1989-2007 …………… 77 Figure 18 – Thermal Offset for Palsa (Dense peat) Compositions 1989-2007 …………………………………………… 79 Figure 19 – Excavated Palsa located in a vegetated region in Northern Ontario …………………………………………………… 115 Figure 20 – Soil Samples baking in the oven at 105˚C for gravimetric soil moisture content analysis …………………………………………… 115 Figure 21 – Three male polar bears in Northern Ontario, August 2007 …… 116

vi List of Tables

Table 1 – Methodology: Environment Canada Weather Station Information with Climate, World Meteorological Organization (WMO) and Transport Canada (TC) ID codes …………………………………… 34 Table 2 – List of Required Materials for Laboratory Analyses: 2007 & 2008 Sampling Campaigns …………………………………………………… 40 Table 3 – Results: Elevation and Annual Temperature Ranges in Northern Ontario communities from Environment Canada …………………… 49 Table 4 – Results: Site & Soil Characterizations from 2007 Soil Sampling Campaign with Distances from the Shores of Hudson Bay to the Sample Sites …… 50 Table 5 – Results: Site & Soil Characterizations from 2008 Soil Sampling Campaign with Distances from the Shores of Hudson Bay to the Sample Sites …… 53 Table 6 – Results: 2007 Laboratory Analysis for Gravimetric Soil Moisture Content and Acidity for Northern Ontario …………………………… 58 Table 7 – Results: 2008 Laboratory Analysis for Gravimetric Soil Moisture Content and Acidity for Sampling Sites along the Shores of Hudson Bay …………………………………………………… 60 Table 8 – Results: 2008 Laboratory Analysis for Gravimetric Soil Moisture Content and Acidity for Sampling Sites inland in Northern Ontario …………………………………………………… 61 Table 9 –Results: Depths to Permafrost for 2007 Sampling Site and Classified By Quadrants …………………………………………………………… 62 Table 10 – Results: Depths to Permafrost for 2008 Sampling Site and Classified by Quadrants …………………………………………………………… 63 Table 11 – Results: Yearly Average Depths to Permafrost per Quadrant …… 64 Table 12 – Results: Statistical Analysis of the 1989-2002 Peawanuck Degree-Days …………………………………………… 65 Table 13 – Results: Statistical Analysis of the 2004-2007 Peawanuck Degree-Days …………………………………………… 67 Table 14 – Results: Stefan Depths for Porous Sand (Porosity >0.33) Soil Compositions (1989-2002) …………………………………… 70 Table 15 – Results: Stefan Depths for Porous Sand (Porosity >0.33) Soil Compositions (2004-2007) …………………………………… 71 Table 16 – Results: Stefan Depths for Non-Porous Sand (Porosity <0.33) Soil Compositions (1989-2002) …………………………………… 73 Table 17 – Results: Stefan Depths for Non-Porous Sand (Porosity <0.33) Soil Compositions (2004-2007) …………………………………… 74 Table 18 – Results: Stephan Depths for Clay Soil Compositions (1989-2002) …………………………………………………………… 75 Table 19 – Results: Stefan Depths for Clay Soil Compositions (2004-2007) …………………………………………………………… 76 Table 20 – Results: Stefan Depths for Peat Compositions (1989-2002) …… 78 Table 21 – Results: Stefan Depths for Peat Compositions (2004-2007) …… 78 Table 22 – Results: Stefan Depths for a Palsa Formation (1989-2007) …… 80 Table 23 – Results: Soil Moisture Content Loss Test (2008) …………… 81

vii CHAPTER 1: Introduction

1.1 Project Description

The formation of permafrost in the Canadian subarctic, particularly in Northern

Ontario, is not widely understood considering the complex relationships between environmental and physical factors (Brown, 1973; Waelbroeck, 1993; Hinkel et al., 2001;

Gough & Leung, 2002; Martini, 2006; Shur & Jorgenson, 2007; Kuhry, 2008). For continuous permafrost presence in a region, climate conditions must be favourable. The presence of permafrost can be determined from climate conditions by calculating the

Frost Number using freezing and thawing degrees-days (Nelson & Outcalt, 1987; Hughes

& Braithwaite, 2008). Based on a hypothesis proposed by Gough and Leung (2002), the influence of soil thermal conductivity in enhancing the penetration of freezing and thawing energies in permafrost, the “thermal offset” phenomenon, is the primary focus of this research. In Gough and Leung (2002), sites in southeastern Hudson Bay followed the

Frost number threshold for continuous permafrost classification. For the southwestern sites of Hudson Bay, the Frost number showed inconsistency with the field observations of continuous permafrost. Gough and Leung (2002) first proposed possible errors in calculations of the thawing degree-days utilized in the Frost number equations. Results from Gough and Leung (2002) concluded that the possible errors such as overestimations in the thawing degree-days due to the usage of monthly means instead of daily temperatures and the influence of snow cover could not account for the inconsistency.

Gough and Leung (2002) proposed that the inconsistency could be explained by the asymmetric thermal properties of frozen and unfrozen soils, the 'thermal offset' phenomenon between different thermal conductivities that are strongly dependant on soil

1 moisture content. For this research, the concept of the penetration of freezing energy into the soil column refers to a negative heat flux of energy in the soil column resulting in the freezing of soils. The concept of the penetration of thawing energy into the soil column refers to a positive heat flux of energy into the soil column that results in melting of frozen soils.

Temperature data was collected from weather stations in the study area for the calculations of the degree-days, which provided the climatological data needed for the

Stefan equation in calculating freezing and thawing depths and thus the thermal offset for the region. Soil samples were retrieved by fieldwork from sampling sites along the shores of Hudson Bay and inland in Northern Ontario. Published literatures on permafrost were reviewed to establish relationships between soil moisture content and thermal conductivity (Gross et al., 1990; Waelbroeck, 1993; Peck & O‟Neill, 1995; Henry, 2000;

Hinkel et al., 2001; Ling & Zhang, 2004; Carey et al., 2007; Shur & Jorgenson, 2007;

Zhang et al., 2008a; Christ & Park, 2009; Duan & Naterer, 2009; Nicolsky et al., 2009;

Wang et al., 2009). Laboratory analysis of the soil samples provided gravimetric soil moisture contents, soil characteristics, and soil acidity. Characterizations and descriptions of the soil samples were conducted to determine the presence of soil organic matter and soil composition. Application of geophysical methods in detecting permafrost and monitoring changes in ground temperatures are discussed in this research (Kurfurst,

1992; Kneisel et al., 2008; Nicolsky et al., 2009).

With climate warming affecting the subarctic regions, shifts in thermal properties can produce unfavourable environmental conditions that can shift permafrost states

(Zoltai & Witt, 1995; Hayashi et al., 2007; Shur & Jorgenson, 2007; Kuhry, 2008; Wang

2 et al., 2009). Potential impacts from shifting permafrost states are further discussed for civil infrastructures in northern communities and on the biodiversity that rely on the current environment (Vyalov et al., 1993; Sorochan & Tolmachev, 2006; Jin et al., 2008;

Duan & Naterer, 2009).

1.2 Aim, Objectives and Hypotheses

The aim of this research is to establish the state of permafrost and palsas in

Northern Ontario and the areas along the shores of Hudson Bay based on field observations during the 2007 and 2008 soil sampling campaigns conducted by Gough of the University of Toronto and Obbard of the Ontario Ministry of Natural Resources. The two main research questions for this thesis are:

1. Can the distribution of permafrost in Northern Ontario be rationalized using the

relationship between soil moisture content and the frozen and unfrozen soil

thermal conductivities, “the thermal offset” as hypothesized by Gough and Leung

(2002)?

2. Does the presence of palsas affect the thermal conductivity of soil from the

surface cover down to the permafrost?

There are four objectives in this research:

The primary objective of this research is to examine the relationship between soil moisture content and soil thermal conductivity through the phenomenon known as

„thermal offset‟ in determining the permafrost state in Northern Ontario and the areas along the shores of Hudson Bay as hypothesized by Gough and Leung (2002).

3 The second objective of this research is to determine the gravimetric soil moisture content and soil acidity in a laboratory setting of the combined 53 samples from retrieved over a two year field sampling campaign, and on going, in Northern Ontario.

The third objective is the characterization of the active layer soil conditions based on field observations of the soil sampling sites in Northern Ontario and the retrieved soil samples from the 2007 and 2008 summer sampling campaigns; the results are to be categorized spatially in quadrants and by shore and inland locations. Locations with the presence of palsas are to be identified since the presence of palsas can affect the soil thermal conductivity. The ecological importance of palsas is considered in relations to polar bear (Ursus maritimus) activities at palsas.

The final and fourth objective of this research is to examine alternative methods to traditional borehole measurements in determining the permafrost state in Canada‟s

Subarctic and Arctic regions with focus on geophysical methods & techniques such as ground temperature borehole logging.

I hypothesize that there should be a relationship between permafrost distribution in the study region and high soil moisture content. Higher soil moisture content increases the soil thermal conductivity especially for frozen soils enhancing the downward freezing effects in the active layer. I also hypothesize that the areas of high moisture content will be in areas of high organic matter, such as peat, moss and small vegetations as this layer is an effective insulator, thus enhancing the freezing effect. Finally, I hypothesize that regions with high moisture content, high organic matter, and climate conditions favourable to permafrost should be dominated with continuous permafrost formation.

4 CHAPTER 2: Literature Review

2.1 Introduction

Research has shown relationships between climatic and soil conditions, such as surface temperature and the moisture content of soil that controls the thermal conductivity of heat energy conducted through the soil column used to diagnose the presence of permafrost (Waelbroeck, 1993; Hinkel et al., 2001; Gough & Leung, 2002;

Seppälä, 2003; Shur & Jorgenson, 2007; Kujala et al., 2007; Zhang et al., 2008b; Pang et al., 2009; Wang et al., 2009).

The active layer above the permafrost is the section of soil that experiences seasonal freezing and thawing cycles. The soil thermal conductivity has an important role in determining the depths of freezing and thawing penetrations from the surface into the active layer that contribute to the evolution of the permafrost. Physically based heat- conduction models (such as the Stefan equation) have been applied using collected field data to estimate seasonal thawing and frost depths (Nixon & McRoberts, 1973; Halliwell

& Rouse, 1987; Nelson & Outcalt, 1987; Anisimov et al., 1997; Gough & Leung, 2002;

Crepeau, 2006; Overduin et al., 2006; Hayashi et al., 2007; Guglielmin et al., 2008;

Hughes & Braithwaite, 2008; Kneisel et al., 2008; Zhang et al., 2008a).

Field sampling and surveys are conducted to monitor the presence of permafrost, the thickness of the active layer and to determine the soil characteristics. Permafrost presence can be determined by drilling boreholes into the subsurface until reaching the permafrost table; this also allows for direct measurements of the active layer thickness.

Confirmation of the presence of permafrost can be accomplished by lowering thermistor

5 probes to measure soil temperatures; permafrost is deemed to be present when temperature is at 0ºC freezing.

Vegetation and peat cover over the active layer is known to have a significant influence on both soil thermal conductivity and soil moisture content. The presence of this top layer allows further protection of the permafrost from climatic extremes

(Seppälä, 1986). Brown (1973), Seppälä (1986), Weidong & Allard (1995), Kujala, et al

(2007), Vallée & Payette (2007), and Kuhry (2008) have linked the influence of peat and vegetation on enhancing the soil thermal conductivity with moisture content in the formation of unique geologic mounds on the permafrost, known as palsas. The presences of palsas were analyzed for the relationships between soil moisture content and the thermal conductivity that governs the rate of permafrost thawing based on field measurements (Seppälä, 1986; Kujala et al., 2007; Kuhry, 2008). While complimenting traditional point-scale borehole samplings on determining permafrost, geophysical methods can be applied to detect frozen soil, ice structures and sediment layers

(Moorman et al., 2003; Kneisel et al., 2008).

2.2 Surface Vegetation and Active Layer

Zoltai & Witt (1995) determined general trends of pH for bogs, fens and peat wetlands in Northern Ontario. Fens are wetlands, region of saturated lands, that are hydrologically influenced by mineral soil deposits (Zoltai & Witt, 1995; Price &

Waddington, 2001). The pH of wet rich fens is above 7.0, basic conditions, while the pH of moderate-rich fens is acidic between pH 5.5 and 7.0 (Zoltai & Witt, 1995). Poor fens and bogs are acidic with pH generally less than 5.5 from humic acid generated by

6 decomposition of the dominant Sphagnum species (Zoltai & Witt, 1995). The surface vegetated layer above the soil column is composed of moss and lichen species, and when partially decomposed over time in bogs, peat is produced (Dunne & Leopold, 1978;

Gross et al., 1990; Zoltai & Witt, 1995; Price & Waddington, 2001). Results from the study of soil moisture content in Sphagnum species conducted by Yoshikawa et al.

(2004) suggested that soil thermal conductivity is sensitive to volumetric soil moisture content. Volumetric soil moisture content is the volume of water per unit volume of soil; this is also reflected as the in situ field capacity (Yoshikawa et al., 2004). Field capacity is the amount of water held in soil after gravitational drainage. Thermal conductivity is a measure of the ability for a medium to transfer heat energy by a gradient (Yoshikawa et al., 2004). The difference in thermal conductivity of dry and moist moss condition is about 1.5 folds; this allows moss on top of permafrost, specifically palsa features, to have a significant impact in the freezing process (Yoshikawa et al., 2004). During the freezing process, formations of ice lenses contribute to frost heaving (Guglielmin et al., 2008).

The process of frost heaving is favourable in ground material with high soil moisture content with organic content (Guglielmin et al., 2008). Water conductive porosity, interconnected pores in soils, contributes to increased soil water content that suggests organic soils can store greater volumes of soil water (Carey et al., 2007). Typical organic soils have 40 to 60% active pore space capable to hold water where active pore spaces have diameters greater than 1x10-5 metres (Carey et al., 2007). Carey et al (2007) noted that larger porosity does not imply greater hydraulic conductivity and the effects of interconnected pores can contribute to soil moisture flow. Organic matter possess greater affinity for water that increase the soil moisture content which in turn enhances the soil

7 thermal conductivity in allowing a greater freezing penetration, i.e. frost depth, and, at the same time, insulation against climatic changes in the environment (Waelbroeck, 1993;

Zoltai & Witt, 1995).

2.3 Permafrost

2.3.1 Defining Permafrost

Permafrost is defined as ground material that remains below 0ºC for at least two consecutive years, a definition based solely on temperature (Gough & Leung, 2002;

Smith & Burgess, 2002; Shur & Jorgenson, 2007). Permafrost is found below the active layer, in the cryotic layer, as the soil in a perennial frozen state (Smith & Burgess, 2002;

Gough & Leung, 2002; Shur & Jorgenson, 2007; Muller, 2008). The surface energy balance, soil moisture content and organic top layer determines the active layer depth

(Gough & Leung, 2002; Muller, 2008). The active layer depth varies throughout the season due to the freeze-thaw cycle, as a response to the thermal gradient between the atmosphere and permafrost (Hinkel et al., 2001; Smith & Burgess, 2002; Muller, 2008).

Climate factors affecting the active layer includes air temperature, annual surface temperatures, extended periods of warming, thickness of overlying organic layer and the presence of snow (Pang et al., 2009). Permafrost is classified under the Cryosol and

Gelisol soil orders due to the presence of cryogenic process such as cryoturbation and ice segregation (Bockheim et al., 2006; Juma 2006).

Shur & Jorgenson (2007) have defined permafrost in a broad sense encompassing time and climatic variation, where three conditions have been developed: the climate favourable to permafrost, climate neutral to permafrost, and climate unfavourable to

8 permafrost. Permafrost is always present where climate is favourable to permafrost and is characterized with the continuous permafrost zonation (Shur & Jorgenson, 2007).

Permafrost is present or absent in the climate neutral condition and is characterized with the discontinuous permafrost zonation (Shur & Jorgenson, 2007). There is no permafrost in regions where there is unfavourable climate condition for permafrost (Shur &

Jorgenson, 2007). Relict permafrost distributions can be observed in unfavourable climate condition where special classification zones can be characterized such as subsea and mountain permafrost (Natural Resources Canada, 2006).

Permafrost classification by Natural Resources Canada (NRCAN) is generalized into continuous, extensive discontinuous, sporadic discontinuous, isolated patches and no permafrost zones based on land surveys, borehole observations and temperature isotherms (French, 1999; Natural Resources Canada, 2006). Continuous permafrost is classified in areas dominated by 90 to 100% permafrost presence, and typically characterized in areas with mean annual temperatures less than –6 ºC (French, 1999;

Natural Resources Canada, 2006). Extensive continuous permafrost is classified in areas containing 50 to 90% permafrost presence (Natural Resources Canada, 2006). Between the 10 to 50% permafrost presence range is classified as sporadic discontinuous permafrost, and typically characterized in areas with mean annual temperatures less than

–1ºC (French, 1999; Natural Resources Canada, 2006). Less than 10% permafrost presence in an area is classified as isolated patches of permafrost with mean annual temperatures less than 0 ºC (French, 1999; Natural Resources Canada, 2006). No permafrost is classified where there is no observed presence of permafrost.

9 In order to calculate and distinguish zones of continuous and discontinuous permafrost, the Frost number (F) using only climatological data can be employed.

Continuous permafrost was calculated to have a Frost number threshold of greater than

0.67. Discontinuous permafrost would be expected at regions with Frost numbers less than 0.67 (Nelson & Outcalt, 1987). The Frost number was defined by Nelson & Outcalt

(1987) as a dimensionless ratio of freezing and thawing degree-day sums:

F = [(FDD0.5) / (FDD0.5 + TDD0.5)], (1)

where FDD is the freezing degree-days and TDD is the thawing degree-days, both in Celsius. Degree-days provide a non-linear relationship between accumulation and annual mean temperatures used in periglacial proxies for permafrost distribution (Hughes

& Braithwaite, 2008). Freezing degree-days are calculated by summing the degrees of the number of days below a threshold temperature, such as 0 degrees Celsius. For thawing degree-days, the similar approach in freezing degree-day calculation is applied with a threshold of days with temperatures greater than 0 degree Celsius. However, the definition of the Frost number threshold does not produce consistent results in the

Hudson Bay region, as seen in Gough & Leung (2002), where as the eastern sites of

Hudson Bay follows the Frost Number threshold and the western and southwestern sites of Hudson Bay do not. The Frost number in the latter instance is below the continuous permafrost threshold at odds with observations.

2.3.2 Formation and Degradation Processes

Permafrost formation occurs on all exposed surfaces in continuous permafrost zones that are controlled by climate (Shur & Jorgenson, 2007). This is known as climate-

10 driven permafrost (Shur & Jorgenson, 2007). The climate driven permafrost can be modified by the ecosystem, this is known as the climate driven, ecosystem-modified permafrost (Shur & Jorgenson, 2007). This complex formation also relies on energy balance, soil thermal properties, evapotranspiration, microclimates and incorporating spatial variation in topography and time (Shur & Jorgenson, 2007). As vegetation develops and peat accumulates, the depth of the active layer becomes saturated with water, enhancing the soil moisture content (Hinkel et al., 2001; Shur & Jorgenson, 2007).

Frost is then allowed to penetrate further into the active layer, reducing the depth (Hinkel et al., 2001; Shur & Jorgenson, 2007). At the same time, the initial active layer base above the permafrost incorporates to the cryotic layer (Hinkel et al., 2001; Shur &

Jorgenson, 2007). The freezing process from the top of the active layer down to the permafrost and up from the permafrost table in autumn is referred by Hinkel et al. (2001) as the “zero curtain regime.”

As Shur & Jorgenson (2007) suggested, permafrost degradation is pronounced in discontinuous permafrost zones due to climate change and disturbances on the surface.

Shur & Jorgenson (2007) discussed four mechanisms of degradation. First, vertical degradation can arise due to a lack of protection from the surface ecosystem, an organic insulating layer, with warmer climate and a positive ground heat flux. The second mechanism of degradation can occur by the removal of protective insulating vegetation above the active soil layer to expose the permafrost to a warmer environment (Shur &

Jorgenson, 2007). The third mechanism includes the lateral degradation of permafrost that can occur from warming and influx of heat from adjacent lakes and groundwater hydrology (Shur & Jorgenson, 2007). Finally, the degradation-aggradation of permafrost

11 adjustments can occur from shifts to the current environmental condition over the landscape that results in an overall net change in the ground heat energy balance, such as changes in snow and organic covers (Hayashi et al., 2007; Shur and Jorgenson, 2007;

Muller 2008).

2.3.3 Soil Moisture Content and Thermal Conductivity

Shur & Jorgenson (2007) suggested that permafrost without a surface organic layer is the least thermally stable. Results from Karunaratne & Burn (2004) suggested that the underlying soil thermal properties have greater influence than the influence of the surface ecosystems. Hinkel et al. (2001) noted that arctic soils, in general, possess a layer of organic material that has large porosity and high hydraulic conductivity. Soil thermal properties can be altered by the soil texture and rates of evapotranspiration by plant life that can influence the soil moisture content (Spielvogel et al., 2004). Evapotranspiration is the transfer of moisture to the atmosphere by photorespiration of vegetation and evaporation process that dominates soil moisture content (Dunne and Leopold, 1978). To calculate thermal conductivity (λ) for the upper peat and organic layers, Hayashi et al.

(2007) suggested applying the de Vries Equation:

λ = (xwλw + kaxaλa + ksxsλs) / (xw+kaxa+ksxs), (2)

where: x is the volume fraction of water (w), air (a) & solid (s),

λ is the thermal conductivity (Wm-1ºC-1), & k is a weighing factor of porosity. The de

Vries Equation accounts for the soil moisture content and porosity that heavily influences the soil thermal conductivity (Zhang et al., 2008a). The de Vries Equation allows the partitioning of the three interfaces of water, air and solid (Hayashi et al., 2007, Zhang et

12 al., 2008a). Shur & Jorgenson (2007) suggests that with thermal conductivity properties of the soil, permafrost would be expected in regions of silty and clayey soils, and seldom in regions with gravely soils.

Conduction of heat energy through the soil column and permafrost can be enhanced by an increase in water content resulting in a greater loss of heat during the winter and greater heat retention in the summer (Shur & Jorgenson, 2007). Hinkel et al.

(2001) found that increased air temperatures does not directly increase the thermal heat flux towards the permafrost through the active layer, but is a surrogate measure of the overall net energy balance entering the ground. Hinkel et al. (2001) mentioned that thermal energies, both freezing and thawing, entering the active layer can be dissipated by near-surface evapotranspiration, as a function of the soil moisture content, initially protecting the permafrost from thawing or degradation in the early spring and fall seasons allowing for a time-lag in the freezing and melting process. With warming temperatures, the increase in runoff and melt water can modify the topography through erosion and affect the underlying permafrost by increasing the soil moisture content (Thie, 1974;

Cline, 1997; Hinkel et al., 2001; Spielvogel et al., 2004; Martini, 2006; Eyles, 2006;

Wang et al., 2009). Soil moisture content can be enhanced over time by the development of drainage networks, increase in precipitation rates, decrease in evaporation rates, and changes in the soil composition (Thie, 1974; Hinkel et al., 2001; Spielvogel et al., 2004;

Martini, 2006; Wang et al., 2009). The soil moisture content is associated with the underlying soil texture as silty and clayey soils will have a higher water content yielding higher thermal conductivities, and gravel soils will have lower water content, yielding lower thermal conductivities (Peck & O‟Neill, 1995; Hinkel et al., 2001; Spielvogel et

13 al., 2004). Shur & Jorgenson (2007) observed that landscape regions of wet organic soils typically had permafrost and landscape with gravely soils had discontinuous permafrost.

The evaporative cooling effect from high moisture content serves as a buffer against temperature variation (Hinkel et al., 2001; Spielvogel et al., 2004). Over prolonged periods of time in moist conditions, insulating peat can develop to provide further buffering against temperature variation by increasing the thermal resistance, inverse of the thermal conductivity (Thie, 1974; Hinkel et al., 2001; Cheng et al., 2004; Spielvogel et al., 2004; Martini, 2006; Zhang et al., 2008b; Pang et al., 2009). Other environmental factors such as snow cover can increase thermal resistance and insulate against warming temperatures (Cline, 1997; Cheng et al., 2004; Osterkamp, 2005; Zhang et al., 2008b).

These complex thermal properties between the peat and snow layers can act to protect the permafrost, keep the permafrost table stable and contribute to permafrost aggradation

(Cheng et al., 2004; Martini, 2006; Zhang et al., 2008b; Pang et al., 2009)

Field soil moisture content and thermal conductivity can be determined using thermistor probes in soil pits (Halliwell & Rouse, 1987; Overduin et al., 2006; Hayashi et al., 2007; Shur & Jorgenson, 2007; Nicolsky et al., 2009). For soil moisture content, another common method is to employ a Time-Domain Reflectometry (TDR) probe at specific depth intervals of the active layer (Halliwell & Rouse, 1987; Pilon et al., 1989;

Hayashi et al., 2007). Neutron probes and gravimetric soil moisture content methods can be used to determine reference field values (Pilon et al., 1989; Hinkel et al., 2001;

Hayashi et al., 2007). Thermal conductivity can be determined using needle probes buried at specific intervals of the active layer and record changes as the active layer

14 thaws (Halliwell & Rouse, 1987; Overduin et al., 2006; Hayashi et al., 2007; Nicolsky et al., 2009).

2.3.4 Stefan Depth and Permafrost Table

Nixon & McRoberts (1973) derived the Frost depth calculation for estimating the depth of active layer thawing and freezing with the thermal conductivities and temperatures. The Frost depth (D) in metres, is represented by the general heat conduction (flux) equation:

0.5 D = [(2nλtTave)/(ρƒL)] , (3) where, λ, the thermal conductivity can be represented as λf, frozen thermal conductivity in the winter season, and λu, the unfrozen thermal conductivity in the summer seasons, n is the n-factor ratio between ground-surface to air temperature (dimensionless), t is the elapsed time since thawing (s), Tave is the mean temperature (ºC), ρ is density of ice

(kgm-3), ƒ is volumetric fraction of ice (dimensionless), and L is the latent heat of fusion of ice (Jkg-1; Nixon & McRoberts, 1973; Nelson, 1986; Broadridge & Pincombe, 1995;

Rees, 2006; Hayashi et al., 2007; Hughes & Braithwaite, 2008). This equation is also known as the Stefan equation (Crepeau, 2006; Hughes & Braithwaite, 2008). A simplified version of the Stefan Equation using degree-days is given as:

D = (2 λ DD/L)0.5, (4) where DD is the Degree-days, for freezing days in the winter, freezing degree-days

(FDD), and for thawing days in the summer, thawing degree-days (TDD).

To represent the summer Stefan thawing layer depth, the equation:

0.5 Du = (2 λu TDD/L) , is applied (5).

15 For Stefan freezing layer depth, the equation:

0.5 Df = (2 λf FDD/L) , is applied (6).

Criteria for a stable permafrost state, based on the Stefan depth calculations, occurs when depths of freezing (Df) is greater than the experienced depths of thawing (Du) in a soil column (Nixon & McRoberts, 1973).

2.3.5 „Thermal Offset‟

„Thermal Offset‟ is a phenomenon as arising from the difference in frozen and unfrozen soil thermal conductivities in units Watts per meter degrees Celsius (Burns &

Smith, 1987). Burns & Smith (1987) characterized „thermal offset” as when a mean annual temperature difference exists between the upper active layer and the permafrost layer. Thermal offset is determined by soil thermal conductivity that in turn is associated with soil moisture (Burns & Smith, 1987). Frozen soils as compared to unfrozen soils have greater thermal conductivities (Kujala et al., 2007). In winter, frozen soils with high soil moisture content allow for a deep downward penetration of cold energies that freezes the soil (Burns & Smith, 1987; Anisimov et al., 1997). In summer, unfrozen soils with low soil moisture content have reduced warming penetrations energies (Burns & Smith,

1987; Anisimov et al., 1997). For cold energy penetration, mean seasonal winter temperatures are applied to the Temperature of Seasonal Depth of Thawing/Freezing

(Thermal Offset) equation:

Df = Du + ΔDλ (7), where ΔDλ in metres is the thermal offset, difference in the thermal properties of the frozen, winter, Df, and thawed, summer, Du, soils from Equations 5 and 6 (Nixon &

16 McRoberts, 1973; Burns & Smith, 1987; Anisimov et al., 1997). The application of the thermal offset calculations provides a more robust method for determining permafrost thickening and degradation over time due to the inclusion of the thermal conductivity factor in the Stefan equation, Equations 3 to 6 (Anisimov et al., 1997).

2.4 Palsa

2.4.1 Defining Palsa

Palsas are geologic formations on continuous and discontinuous permafrost zones in the subarctic regions possessing a permafrost core and alternating layers of segregated ice that form lenses (Seppälä, 1986; Weidong & Allard, 1995; Kujala, et al., 2007).

Palsas have been observed in Canada, Finland, Iceland, Alaska and Siberia (Seppälä,

1986; Weidong & Allard, 1995; Kujala, et al., 2007; Vallée & Payette, 2007; Kuhry,

2008). In Canada, palsas have been documented in Northern Québec, Northern Ontario and Northern Manitoba (Brown, 1973; Weidong & Allard, 1995; Vallée & Payette,

2007). Palsas appear as thick mounds or circular-domed elevation of terrain (Brown,

1973; Seppälä, 1986; Kujala, et al., 2007; Kuhry, 2008; Figure 1). These mounds can have a height up to a few metres and diameters from tens to hundreds of metres and are carbon pools due to the vast amount of organic materials (Brown, 1973; Seppälä, 1986;

Kujala, et al., 2007; Kuhry, 2008). Luoto & Seppälä (2002) classified palsas to be typically present in flat areas adjacent to water bodies with the presence of organic materials.

Figure 1 – “Baby” Palsa in Northern Ontario, August 2007. Photo by: William Gough.

The internal core of the palsa is composed of frozen peat, silt and layers of frozen ice

(Seppälä, 1986). It should be mentioned that palsa research is limited to a few selected authors (Brown, 1973; Seppälä, 1986; Weidong & Allard, 1995; Kujala, et al., 2007;

Vallée & Payette, 2007; Kuhry, 2008).

2.4.2 Physical Properties of Palsas

Palsas are usually found in regions of high acidic peat formation typically a bog wetland (Brown, 1973; Seppälä, 2003). Kujala et al. (2007) determined physical properties of the palsa mounds, peat was collected and the pH was determined to be 3.4 and the water content was 79% of the total mass by weight. Studies on palsa formation and height by Seppälä (1986) suggested that during the summer season, the peat layer is dryer and has a lower thermal conductivity. During the fall season, peat thermal

18 conductivity increases as freezing and water content increases in the peat (Brown, 1973;

Seppälä, 1986; Kujala, et al., 2007). This increase in peat thermal conductivity allows the frost and cold to penetrate deeply into the palsa to enhance freezing of the ice lenses

(Kujala, et al., 2007; Kuhry, 2008). The presence of snowfall in the winter season tends to decrease the thermal conductivity preventing the cold penetration effect (Kuhry, 2008).

Frost heave contributes to the dome-like feature of palsa from the freezing of soil moisture in establishing the ice lenses (Seppälä, 1986; Henry, 2000; Kujala, et al., 2007;

Guglielmin et al., 2008; Kuhry, 2008). Kuhry (2008) suggest that landforms associated with permafrost include palsa hummocks, peat plateaus and polygonal peat plateaus.

These landforms contribute to modifying the topography that may further influence soil moisture by altering the local hydrology, water drainage pathways (Martini, 2006; Kuhry,

2008; Wang et al., 2009). Luoto & Seppälä (2002) suggests a complex spatial and temporal interaction where palsas should mostly occur in areas that have undergone periods of warm temperatures that provided significant soil moisture followed by seasonal freezing. Kujala et al (2007) demonstrated that the thermal conductivity could be enhanced with high moisture content (65%) for both frozen (1.5 Wkm-1) and unfrozen

(0.5 Wkm-1) soils when compared to low moisture content (56%) for frozen (0.6 Wkm-1) and unfrozen (0.2 Wkm-1) soils. Since water has a higher energy transfer rate as solid ice than in the liquid phase, the overall conductivity is greater at 1.5 Wkm-1 for frozen compared to 0.5 Wkm-1 for unfrozen soils (Kujala, et al., 2007. The frozen peat layer acts as an insulating layer during the next summer seasons to prevent thawing or heat penetration promoting growth (Kujala, et al., 2007).

19 2.4.3 “Palsa Lifting”

Palsa growth in height is referred to as „lifting of the palsa‟ by Seppälä (1986) due to the buoyancy properties of the ice core on wet peat where water is collected and stored into the core, thus increasing its volume. The height of a palsa determines the extent in which thawing can penetrate the mound. As freezing occurs downward, capillary water is collected beneath the freezing layer, this process contributes to the formation of ice lenses that segregate frozen peat layers (Brown, 1973; Seppälä, 1986; Kujala, et al., 2007;

Kuhry, 2008). The ice lens formation is also an extension of the permafrost, thus results in the reduction of the base of the active layer. Experiments in man-made palsas by

Seppälä in 1982 illustrated this effect as frost was able to penetrate 70 cm downward into the core of the palsas, and after two summers, 15-30 cm of the frost was still detectable in

October 1985 (Seppälä, 1986).

2.4.4 The Palsa Cycle

Seppälä (2003) noted the presence of Lycopodium annutinum, Huperzia selego,

Polytricum mosses and Cladonia lichens on newly developed palsas in the Finnish

Lapland. Depending on the region, palsa formation is observed in poorly drained areas such as fens and bogs are dominated by Sphagnum species (Zoltai & Witt, 1995; Seppälä,

2003). Peat formation in bogs occurs over time as partial degradation of vegetation, such as moss, into carbon organic matter (Zoltai & Witt, 1995). Seppälä (1986) suggests that in order for palsa to begin the formation process, it would need a 50 cm thick insulating layer of peat to develop first. The top layer cover then acts as an insulating layer and with

20 high moisture content, the thermal conductivity increases allowing deep frost penetration

(Seppälä, 1986).

The edges of the palsas are characterized as sharp steep edges that collect drifting snow, however, since palsa freezing occurs from above towards the core, the edges remain warmer and unfrozen (Seppälä, 1986). The collection of drifting snow by wind is also a driver for palsa formation by acting as an insulating layer (Seppälä, 1986). Thin layers of snow cover in the winter allow frost and cold to penetrate deeper into the peat than with thick layers of snow. As the wind carries away the snow layer, the frost penetration is enhanced, thus increasing the freezing of the peat. The growth of palsas is not continuous, after a maximum height (about 7m to 12m), usually characterized by formation of the sharp edges for snow drift collection and a top plateau, the frost layer can no longer increase in thickness (Seppälä, 1986). In the summer, instead of snowdrift, blowouts of sand dunes and glaciofluvial deposits of fine sands can become layered in the palsa (Seppälä, 2003).

Seppälä (2003) acknowledged that blockside erosion due to rise in height allow the formation of cracks. Enhanced by wind interactions, the edges of the palsas begin to collapse, which signifies the degradation stages, and pools of water surrounding the palsa form (Seppälä, 1986; Seppälä, 2003). Intense wind speeds above 50 m s-1 can enhance erosion and degradation of the palsa (Seppälä, 1986; Seppälä, 2003). Internally, the ice core may begin to melt causing an internal collapse of the palsa as a pond forms in its place. The formation of a circular pit in the topography usually signifies a „dead‟ palsa formation (Seppälä, 1986). However, this formation and degradation process was suggested to be cyclic as new peat can develop in the ponds and pits created by remnant

21 palsas, and over time, provide the foundation for a new palsa core for development

(Seppälä, 1986). The degradation of a particular palsa may not necessarily be attributed to climate change as suggested by Seppälä (1986) since the mechanism may be due to this cyclic process over time.

2.5 Soil Temperatures and Net Radiation

A standard method for determining the presence of permafrost is to measure the soil temperatures (Pilon et al., 1989; Mühll et al., 2002; Smith & Burgess, 2002; Kneisel et al., 2008; Nicolsky, 2009). To measure soil temperatures, thermistors are deployed in the active layer at set intervals (Pilon et al., 1989; Nicolsky, 2009). Thermistors are defined as semi-conductor probes that measure electrical resistance in relation to temperature (Pilon et al., 1989; Mühll et al., 2002; Nicolsky, 2009). Thermistors record continuous time series of temperature data onto data loggers. The data loggers record and allow the data to be downloaded later. Thermistors connected in series form a thermistor cable (Pilon et al., 1989).

Surface temperature can be determined by using an infrared thermocouple sensor or calculated by applying the Stefan-Boltzmann Equation:

4 εσTs = Qlw↑ + (1-ε)Qlw↓, (8) where ε is the emissivity, σ is the Stefan-Boltzmann Constant (5.67x10-8 Wm-2K-4), Ts is

-2 the surface temperature (Kelvin), Qlw↑ is the reflected longwave radiation (Wm ), Qlw↓ is the sky longwave radiation (Wm-2; Crepeau, 2006). Incoming and outgoing shortwave and longwave radiations can be measured using a four-component radiometer (Hayashi et al., 2007).

22 2.6 Ground Heat Flux

Halliwell & Rouse (1987) stated that buried soil heat flux plates are the standard method in measuring ground heat flux. A soil heat flux plate is composed of a thermopile, encased in an electrically insulating material that is placed between two metallic plates (Halliwell & Rouse, 1987; Wen et al., 2008). When buried in the soil layer, the heat flux passing through the plate results in a temperature difference across the thermopile that is proportional to the flux density where a voltage output from the thermopile can be measured and continuously recorded on data loggers (Halliwell &

Rouse, 1987).

Hayashi et al (2007) suggested that ground heat flux (Qg) for the energy balance of the active layer consists of three components and can be calculated from the calorimetric method:

-2 Qg = Qi + Qs + Qp, in Watts per square metre (Wm ). (9)

Qi is the latent heat used to melt ice in the active layer represented by the

equation: Qi = ρƒLΔz, (10) where ρ is density of ice (kgm-3), ƒ is volumetric fraction of ice (unit less), L is the latent heat of fusion (Jkg-1), Δz is rate of frost table depth change (m).

Qs is the heat that warms the active layer represented by the equation:

Qs = Σi CidiΔTi, (11)

where „i‟ represents the location of soil thermistor of the thermistor cable, Ci is

-3 -1 volumetric heat capacity (MJm ºC ), di is thickness (m), ΔTi is rate of daily

temperature change (ºC).

Finally, Qp is heat conducted into the permafrost layer from the upper active layer.

23 2.7 Geophysical Detection of Permafrost

With warming temperatures in polar regions, concerns of warming-induced permafrost degradation, northern expansion of infrastructures, and the movement of contaminants in the once frozen subsurface have driven the need for geophysical methods to be applied in determining the extent of permafrost (Delaney et al., 2001; Tsuji et al.,

2001; Smith & Burgess, 2002; Sorochan & Tolmachev, 2006; Kalinovich et al., 2008;

Kneisel et al., 2008; Wang et al., 2009). Geophysical methods are applied to investigate and characterize subsurface conditions over large areas. It should be noted that there is no set standard geophysical method in determining permafrost (Pilon et al., 1989; Kurfurst,

1992; Hinkel et al., 2001; Nieto & Stewart, 2002; Smith & Burgess, 2002; Mühll et al.,

2002; Moorman et al., 2003; Kneisel et al., 2008). Kneisel et al. (2008) stated that most geophysical methods for permafrost were derived from application of geophysical methods from geological survey methods and petroleum exploration techniques since the

1970s. Certain methods have advantages in determining permafrost, such as detecting boundary transitions, structures and sediment layers, but the same method will have limitations, such as depth, resolution, misidentification of ice and rock, and the scale of application. Since drilling borehole operations in permafrost is often expensive, time consuming and logistically demanding, this is one of the main reasons in employing geophysical methods (Tsuji et al., 2001; Mühll et al., 2002; Moorman et al., 2003; Saito

& Yoshikawa, 2007; Kneisel et al., 2008; Nicolsky, 2009).

24 2.7.1 Ground Temperature Borehole Logging

A classical method to determining the presence of permafrost is to measure the ground temperatures (Pilon et al., 1989; Mühll et al., 2002; Smith & Burgess, 2002;

Kneisel et al., 2008; Nicolsky et al., 2009). To measure temperatures, thermistors are deployed vertically in the subsurface usually in boreholes (Pilon et al., 1989; Kurfurst,

1992; Mühll et al., 2002; Nicolsky et al., 2009). Thermistors are semi-conductor probes that measure electrical resistance in relation to temperature (Pilon et al., 1989; Mühll et al., 2002; Nicolsky et al., 2009). Thermistors record continuous time series of temperature data onto data loggers. The data loggers sort and allow the data to be downloaded later. Thermistors can be connected in series to a Thermistor cable (Pilon et al., 1989). Installation of thermistor cables occurs as an opportunistic operation following excavation and borehole drilling operations (Mühll et al., 2002; Nicolsky et al., 2009).

This approach allows the collection of more data and reduces the expense in separate borehole drillings (Mühll et al., 2002; Nicolsky et al., 2009). Permafrost is determined to be present when ground temperatures are below 0ºC (Smith & Burgess, 2002). The boreholes are typically encased using porous polyvinyl chloride (PVC) pipes where the thermistor cable can be lowered into the subsurface (Kurfurst, 1992). However, the protective PVC pipe can act as thermal contaminator and insulator that affects the temperature measurements, this occurrence is referred to as “leaky cables” (Pilon et al.,

1989).

Borehole logging requires drilling into the subsurface (Saito & Yoshikawa, 2007;

Nicolsky et al., 2009). Three main types of drilling used in determining permafrost depths are percussion, rotary and auger drillings. Percussion drilling requires the use of

25 heavy equipment and gasoline-powered machinery at the study site, and utilizes a weight to create an impact force that bores through the subsurface material (Saito & Yoshikawa,

2007). Rotary drills utilize torque and axial forces with various drilling bits to create a borehole that displace ground material by helical flighting along the axis of rotation of the drill bit (Saito & Yoshikawa, 2007). Once the borehole is created, probes connected to loggers by a wire are placed down the boreholes. However, not all boreholes can be used due to the diameter of the hole, the presence of frozen fluids, and the stability of the borehole walls (Saito & Yoshikawa, 2007). The presences of frozen fluids act as a barrier against the probe from being lowered to the depth of the borehole. The stability of borehole walls can be reinforced by inserting wall casings (Saito & Yoshikawa, 2007).

2.8 Literature Summary

Arctic soils are characterized by an upper organic layer, followed by an active layer that varies in depth by season and underlain by permafrost that is ground material frozen for at least two years (Waelbroeck, 1993; Gough & Leung, 2002). The high moisture content of the peat and organic layer was determined to have a soil moisture range of 16 to 65% by volume and indicated that the increase of moisture content allows for greater dielectric conductance (Yoshikawa et al., 2004). Continuous permafrost is present in climate favourable conditions and in regions dominated by a negative ground heat energy balance. Gough & Leung (2002) determined inconsistencies with the Frost number thresholds for characterizing permafrost presence along the western shores of

Hudson Bay and in Northern Ontario and suggested a greater role in the thermal conductivity properties. Shur & Jorgenson (2007) suggested that freezing penetration

26 downwards into the active layer of the soil is enhanced by increased moisture content that enhanced the thermal conductivity of energy transfer. Moisture content and insulation provided by overlying vegetation and organic layers enhance the soil thermal conductivity properties that allows for greater freezing penetration (Karunaratne and

Burn, 2004; Shur and Jorgenson, 2007; Wang et al., 2009). Removal of the vegetation and organic layers reduces the insulation effect allowing for various degradation methods of permafrost to occur (Karunaratne & Burn, 2004; Shur & Jorgenson, 2007; Zhang et al., 2008b; Pang et al., 2009). Karunaratne & Burn (2004) and Shur & Jorgenson (2007) suggested that the composition of the soil could determine the presence of permafrost, as presence would be expected in regions of silty and clayey soils, and seldom in regions with gravely soils due to the textures ability to retain moisture content. Soil moisture content heavily influences the soil thermal conductivity that allows the conduction of the thermal freezing and thawing energies into the soil column (Wang et al., 2009). A thermal offset phenomenon favourable to permafrost presence occurs when freezing energies in the winter season exceeds the summer thawing energy penetration, positive heat flux, in the soil column resulting in a thickened frozen soil layer (Burns & Smith,

1987). Enhanced freezing can occur in highly saturated active layers above the permafrost, the formation of palsas can result from the development of an ice lens that cause a volumetric expansion of the soil to produce mounds (Brown, 1973; Seppälä,

1986; Kujala, et al., 2007; Kuhry, 2008). This cyclic process is influenced by vegetation, atmospheric conditions, and soil thermal conductivity, that can be enhanced by the soil moisture content, that enables downward freezing penetration into the soil, negative heat flux (Seppälä, 1986; Kujala, et al., 2007). Hayashi et al (2007) suggested that the heat

27 and mass transfer equation can be coupled to simulate the thawing and freezing depths by applying the Stefan equation based on the soil thermal conductivity, soil moisture content and atmospheric forcing.

With northern climates predicted to continue on a warming trend, the increased likelihood for environmental disturbances, such as permafrost and palsa degradation, are expected and the changes will affect local wildlife and northern communities (Seppälä,

1986; Vyalov et al., 1993; Anisimov & Nelson, 1996; Sorochan & Tolmachev, 2006;

Kujala et al., 2007; Dyck et al., 2007; Callaghan, 2008; Crompton et al., 2008). Polar bear (Ursus maritimus) habitats have been identified in Northern Ontario that is dominated by permafrost and palsas (Callaghan, 2008; Crompton et al., 2008). In spring, female polar bears display site fidelity behaviour by returning to dens that were established in the previous year (Crompton et al., 2008). This site fidelity behaviour is even prominent over feeding needs suggesting that shifts in permafrost may affect the ecology of the region causing disturbances to the site fidelity behaviour, reducing the survival fitness of cubs (Crompton et al., 2008; Dyck et al., 2008). Changes in the ecology from shifts in permafrost may affect local food sources for polar bears affecting the den locations and survival (Dyck et al., 2008).

Permafrost distribution and active layer monitoring involves high quality atmospheric, soil, and hydrological data that can be collected using the standard borehole, soil temperature and atmospheric measurements that can be complimented for larger spatial scale with modern geophysical tools. Shifts in the permafrost will pose a greater threat for engineering designs on infrastructures in aboriginal communities infrastructures and for the industrial pipelines that traverse Canada‟s North. The phase change of water

28 to ice increases the soil strength by the process of cementation, however, the degradation of permafrost can significantly weaken the strength of soil and reduce the load bearing that can prove hazardous to human infrastructures and transportation networks (Christ &

Park, 2009). With warming temperatures and seasonal frost heaving processes, the expansion and melting of the ice in frozen ground can result in both sudden and gradual changes to infrastructure foundations that can compromise the structural stability and safety of buildings (Ling & Zhang, 2004; Kim et al., 2008; Larsen et al., 2008; Christ &

Park, 2009; Duan & Naterer, 2009). Understanding and predicting the permafrost state is important in engineering protocols in order to minimize risks to human safety and for the environment (Vyalov et al., 1993; Sorochan & Tolmachev, 2006; Dyck et al., 2007;

Callaghan, 2008; Crompton et al., 2008; Kim et al., 2008; Larsen et al., 2008; Christ &

Park, 2009; Duan & Naterer, 2009).

29 CHAPTER 3: Experimental Design and Methodology

Two field-sampling campaigns were completed in mid-August of 2007 and 2008 along the shores of Hudson Bay and inland Northern Ontario. Gough and personnel from the Ontario Ministry of Natural Resources conducted sampling and fieldwork. The study area is located between 54º28.909 north to 56º47.759 north and from 83º36.585 west to

89º30.534 west from the shores of Hudson Bay to within 100 kilometres inland of

Northern Ontario (Figure 2).

Figure 2 – Location of settlements, weather stations and rivers in Northern Ontario. Map produced with Manifold V.7 GIS software with UTM projection 16

30 3.1 Location and Study Site Descriptions

The communities of Peawanuck, Ontario, and Fort Severn 89, Ontario, are located within the study area. The Indian Settlement of Peawanuck (55°00.500 N, 85°25.333 W) is located in the Kenora District; governed by the Weenusk First Nation Band, provincially by the Government of Ontario, and federally by the Government of Canada

(Figure 2). According to the 2001 Census conducted by Statistics Canada, the permanent population count for Peawanuck is 193 (Statistics Canada, 2007). An updated count by the Weenusk First Nation in 2007 showed a population of 300 (Weenusk First Nation,

2007a). The Peawanuck community is bilingual in Cree and English. Peawanuck is bordered by Polar Bear Provincial Park and located near the Winisk River.

The First Nation Reserve of Fort Severn 89 (56°00.000 N, 87°21.000 W) is located near the Severn River. Fort Severn is governed by the Cree First Nation, provincially by the Government of Ontario, and federally by the Government of Canada

(Figure 2). The permanent population for Fort Severn is 639 as reported by the Indian and

Northern Affairs Canada registration (Indian and Northern Affairs Canada, 2008). Both

Fort Severn and Peawanuck are accessible by boat in the summer season and by air service all year round. Ice roads connect the two First Nation communities during the winter season.

It should be referenced that the ghost town of Winisk (55°15.402 N, 85°12.396

W), referred as Weenusk in Cree, Ontario, was the original Indian Settlement location before the establishment of Peawanuck, Ontario (Figure 2). Winisk is located along the

Winisk River. The Winisk Flood of 1986 destroyed the settlement and resulted in the relocation and establishment of Peawanuck, Ontario, about 35 kilometres to the south.

31 Winisk is a historical military radar site. The Royal Canadian Air Force (RCAF) Station

Winisk and airfield were established in the late 1950‟s as part of the Mid-Canada Line to provide early warning radar detection against intercontinental ballistic missiles (Tsuji et al., 2001). The Department of National Defence, in the mid-1960s, decommissioned the station; however, there remain environmental concerns at this site (Tsuji et al., 2001).

3.1.1 Biogeography

The terrestrial ecozone for Fort Severn and Peawanuck, Ontario, is classified as the Hudson Plains, located north of the Boreal Plains, in between the Taiga Shield, and south of the Southern Arctic ecozone (Figure 3; Natural Resources Canada, 2007).

Figure 3 – Terrestrial Ecozones for the Hudson Bay Lowlands by Natural Resources Canada (Natural Resources Canada, 2007)

32 Fort Severn and Peawanuck are dominated by subarctic vegetation that includes open trees, shrubs, and wildflowers; this region is located in the Transitional Forest ecozone and north of the Boreal Coniferous ecozone (Figure 4; Natural Resources Canada, 2003).

Figure 4 – Forested Ecozones for the Hudson Bay Lowlands by Natural Resources Canada (Natural Resources Canada, 2003)

Peawanuck is located in the Hudson Bay Lowlands along the Winisk River, where swamps, bogs and muskeg areas are found in adjacent wet areas (Figure 2). Fort

Severn is located to the west of Peawanuck near the mouth of the Severn River (Figure

2). The wildlife in the Fort Severn and Peawanuck regions are briefly listed as: Beaver,

Black Bear, Polar Bear, Caribou, Ermine, Arctic Fox, Red Fox, Snowshoe Hares, Lynx,

Moose, Otter, Mink, Muskrats, Snowy Owl, Crow and Wolf. Water Fowl included:

33 Canada Geese, Snow Geese, Swans, Sand Hill Crane, Loons and Ducks. Along the

Hudson Bay shores, it is typical to see: Walrus, Beluga Whales, and Seal (Weenusk First

Nation, 2007b). During the 2008 summer sampling campaign, the following were observed in the study area: Caribou, Polar Bear, Eagle, Snow Geese, Loons, Whale, and

Sand Hill Crane.

3.1.2 Climate Data and Weather Stations

Weather stations located in the study area within the Hudson Bay watershed as listed in use by Environment Canada Weather Office: Fort Severn (A) and Peawanuck

(AUT; Environment Canada, 2009a; Environment Canada, 2009b). Weather station descriptions are shown in Table 1 and Figure 2.

Table 1 – Methodology: Environment Canada Weather Station Information with Climate, World Meteorological Organization (WMO) and Transport Canada (TC) ID codes. (Environment Canada, 2009a; Environment Canada, 2009b) Location Latitude Longitude Climate ID WMO ID TC ID Fort Severn (A) 56°1.200' N 87°40.800' W 6012500 71099 YER Peawanuck 54°58.800' N 85°25.800' W 6016295 71434 WWN (AUT)

Average snow depths in centimetres, mean annual precipitation in millimetres, soil and air temperatures in degrees Celsius, and permafrost zones were collected from

Environment Canada Weather Office stations in Peawanuck and Fort Severn, Ontario, and from the Atlas of Canada of the Natural Resources of Canada, respectively

(Environment Canada, 2009a; Environment Canada, 2009b; Natural Resources Canada,

2006). Weather stations were installed in the 2008 summer campaign at the 2007 sampling-site of G5a/8E3 (Shagamu) (55°41.102 N, 86°51.325 W) and near 8A1 Burnt

Point (55°14.507 N, 84°19.032 W) by the Ontario Ministry of Natural Resources to

34 provide snow depth, air and soil temperature data and wind speed. This site is situated between Fort Severn and Peawanuck, Ontario (Figure 2).

3.2 Field Experimental Design

3.2.1 Soil Temperatures and Thermistor Probes

Soil temperatures were determined using thermistor probes that were lowered into a borehole created by the hand auger. The depths to the permafrost were measured by using a graded rod. Permafrost presence was determined when soil temperature was at freezing, 0ºC; the temperatures were recorded in the field notes.

3.2.2 Point-scale Geophysical Sampling

A total of 53 soil samples were collected in the two-year sampling campaign; 20 and 33 soil samples retrieved in August of 2007 and 2008, respectively (Figure 5). Within the study area, observations were made at over 500 sites.

Figure 5 – Sampling Sites located in Northern Ontario Hudson Bay divided by Three Quadrants from both 2007 and 2008 Soil Sampling Campaigns. Map produced with Manifold V.7 GIS software with UTM projection 16

A hand auger was used to produce a borehole where soil samples from the surface, 30 and 120-centimeter depths were extracted and collected in plastic containers and double plastic Ziploc bags (Table 2). Upon reaching the permafrost, the solid state of ground prevented further auguring deeper into the subsurface, which can be confirmed by lowering and striking a graded rod in the borehole. The soil samples were transported back to the University of Toronto Scarborough campus. Helicopter support was used for transportation to the sampling locations. The depths to the permafrost were determined by lowering the graded rod into augured boreholes for measurements in centimetres.

Using Figure 2, the study area was divided into three quadrants (Figure 5).

Quadrant 1 included all the sampling sites in 2007 and 2008 that were located between

36 the provincial boundary line of Ontario and Manitoba and the western portion of the

Severn River (Figure 5; Tables 9 and 10). Quadrant 2 was divided to include all the sampling sites in 2007 and 2008 that were located between the eastern portion of the

Severn River and the western portion of the Winisk Rivers (Figure 5; Tables 9 and 10).

Quadrant 3 included all the sampling sites in 2007 and 2008 that were located between the eastern portion of the Winisk River and to the shores of James Bay (Figure 5; Tables

9 and 10). Figure 6 was produced to show the 2007 sampling campaign.

Figure 6 – Sampling Sites located in Northern Ontario - Hudson Bay for 2007 divided by Three Quadrants. Map produced with Manifold V.7 GIS software with UTM projection 16

Figure 7 was produced to show the 2008 sampling campaign.

Figure 7 – Sampling Sites located in Northern Ontario - Hudson Bay for 2008 by Three Quadrants. Map produced with Manifold V.7 GIS software with UTM projection 16

3.2.3 Sample Labelling and Identification

Each soil-sampling site from the study site was geo-referenced using a hand-held global positioning satellite (GPS) system. Soil samples retrieved from the 2007 sampling campaign were labelled with a unique identification key that corresponded with the recorded field data in the field notes. For example, Sample “B1” represented a sample from site „B‟ made on the „first‟ day of the campaign. This was conducted for all 20 samples in 2007. For the 2008 soil sampling campaign, the samples were labelled with a second identification key that corresponded to the field notes. For example, Sample

“8A1”, „8‟ represents the „month of August‟ for sampling at site „A‟ on the „first‟ day.

This was conducted for all 33 samples in 2008 (Figure 8). The labelled soil samples, site

38 coordinates, temperature data, and the depths to permafrost measurements were recorded in the field notes. Additional field data were recorded in picture documentation.

3.2.4 Field Soil Characterization

The soil properties in the field were characterized based on visual and physical observations of colour, texture, and soil moisture that were recorded in the field notes.

The presence of organic areas, such as peat layers, bogs, fens, and the lack of organics were noted in the field notes. Additional field data were recorded in picture documentation. Soil samples were collected at the point-scale resolution into containers and labelled appropriately before being transported to the University of Toronto

Scarborough campus for further in-depth analysis.

3.3 Laboratory Analytical Methodology

The soil samples retrieved from the 2007 sampling campaign were analyzed on October

4th of 2007. The samples from the 2008 soil-sampling campaign were analyzed on

October 27th of 2008. Both laboratory analyses were conducted at the University of

Toronto Scarborough campus. Laboratory methodology for soil moisture and acidity analyses was adapted from the GLOBE (2005) protocol soil techniques.

3.3.1 List of Materials

The materials required for the soil sampling campaign and laboratory analysis in

2007 and 2008 are listed in Table 2.

39 Table 2 – Methodology List of Required Materials for Laboratory Analyses: 2007 & 2008 Sampling Campaigns. 2007 Campaign 2008 Campaign 20 soil samples containers 80 Ziploc Bags 20 200 ml Erlenmeyer beakers, 33 200 ml Erlenmeyer beakers, 20 tin foil baking trays, 33 tin foil trays, 2 glass stir rods, 2 glass stir rods, 2 metal tablespoons, 2 metal tablespoons, 2 Litres distilled water, 5 Litres distilled water, 1 graduated 100mL cylinder 1 graduated 100 mL cylinder 1 TDS pH meter, 1 Symphony SB70P pH meter, 1 25mL pH 7 buffer solution, 1 25 mL pH 7 buffer solution, Baking oven, mass balance, and 1 25 mL pH 10 buffer solution, paper towels. Baking oven, mass balance (Denver Instrument MXX-2001), and paper towels

3.3.2 Laboratory Soil Characterization

In depth soil characterization of the retrieved soil samples were conducted at the

University of Toronto Scarborough campus soil laboratory. The labelled samples were transferred from the sample containers into corresponding labelled tinfoil trays (Figure

8).

Figure 8 – Labeled sample bag with associated tin foil tray container: Sample 8A1a with sandy & rocky materials. Picture was taken on 4 OCT 08 by A. Tam

40 By using a glass stir rod, the sample could be dispersed (Figure 9).

Figure 9 – Analysis of soil sample D5a: Presence of fungus and partially decomposing organic material. Picture was taken on 4 OCT 07 by A. Tam.

Observations were noted based on colour, texture, moisture content, the presence of partially decomposed vegetation, presence of rocks and pebbles, aggregation, and any unique characteristics such as fungus and moulds (Figure 9).

3.3.3 Gravimetric Soil Moisture Content

The gravimetric soil moisture content, θm, in percentage was determined using the outlined principles and procedures outlined by Juma (2006), supported by the

GLOBE (2005) protocol. The mass of the tin trays, Tm, plastic sample container, Cm, and bag, Bm, were determined and recorded using an electronic mass balance in units of grams, g. The tinfoil trays containing the soil samples were placed onto a mass balance to determine the Initial Total Mass, ITm. The initial total mass of the soil samples included

41 both the masses of the plastic sample container, Cm, and bag, Bm. To determine the soil moisture mass, Wm, the mass of the plastic container and bag were subtracted from the initial total mass (Equations 12 & 12a). In 2007 laboratory analysis, the Wm was determined using the following equation:

(ITm) - [(Cm) + (Bm)] = (Wm). (12)

For the 2008 laboratory analysis, Equation 15 was modified to determine the Wm:

(ITm) - [(Bm)] = (Wm) (12a)

The tinfoil trays were then placed into the baking oven at the University of Toronto at

Scarborough Soil Lab at 105˚C for 24 hours (1 day) before being removed from the oven

(Figure 20), the tinfoil trays and soil samples were cooled down to ambient room temperature (22°C) for 15 minutes, and the Final total mass, FTm, was recorded by the mass balance.

To determine the mass of the oven-dried soil, ODSm, the final mass of the sample and tray after drying, FTm, was subtracted by the mass of the tin tray, Tm:

(FTm) - (Tm) = (ODSm) (13)

To determine the soil moisture (Ws), the mass of the oven-dried soil was subtracted from the soil moisture mass:

[(Wm) - (ODSm)] = (Ws) (14)

To determine the water content in percentage, θm, Ws was divided by Wm then multiplied by 100:

(θm in %) = [(Ws) / (Wm)] * 100 (15)

This was repeated for all samples. The dried oven soil was collected back into the containers for storage.

42 3.3.4 Soil Acidity, Average pH Value

To calibrate the pH probe, the probe tip was washed with distilled water and immersed in a pH7 buffer solution for calibration as directed by the manufacturer‟s specifications in calibration. To determine the acidity of the soil sample, 50 grams of oven dried soil was measured and placed in a 200 ml Erlenmeyer beaker and 100 ml of distilled water was added. The solution was manually stirred with a glass-stirring rod for

5 minutes before being left to settle for 15 minutes. After 15 minutes, the pH probe was lowered into the solution for two minutes, and the pH value was recorded. Three trials were conducted per each soil sample. The pH values were converted to the concentration of Hydrogen, [H+]:

pH = -log[H+] , [H+] = [1/(10^pH)]. (16)

The arithmetic average of the concentration of Hydrogen of each 3 trials (Trial1,

Trial2, Trial3) per sample was calculated and recorded:

{[([H+] Trial1) + … + ([H+] Trial3)] / 3} = (mean [H+]). (17)

Finally, using Equation 16, the mean concentration of Hydrogen was converted back to the mean pH value. This was repeated for all samples. The solutions were safely disposed in the soil laboratory waste bins.

3.3.5 Soil Moisture Content Loss Test

A control test for water content loss by evaporation of the soil samples in the plastic bag containment was conducted for 35 days (5 weeks) from March 4thto April 8th,

2008 using 9 control samples where plastic bags were filled with water and placed at various locations around the University of Toronto Scarborough campus.

43 A mass water balance approach was applied for the soil moisture content control test. The mass of the plastic containment bag, Mbag, was determined using an electronic mass balance. Using a graduated 100 mL cylinder, 50 mL of ordinary water from the laboratory was poured and sealed in the plastic bags then placed on the mass balance to determine the total mass, Mbw. The mass of water, Mw, in grams was determined by the equation:

[(Mbw) – (Mbag)] = (Mw). (18)

To convert Mw, in grams, to a volume in millilitres, Vw, the density of water at

23ºCelsius (0.9975 g/mL) can be used:

[(Mw) (g) / (0.9975 g/mL)] = (Vw). (19)

This process was repeated nine times for 9 control samples. The 9 control samples were labelled with a unique identification key that corresponded with the laboratory notes. For example, Sample “T1”, „T‟ represents the “Test” sample designation while „1‟ refers to

„Location #1‟. Initial leak test of the test samples were conducted and recorded to determine if the containment was compromised. Three test samples had one-level of containment, a seal single layer plastic bag with 50 mL of water. The next three test samples had a two-level containment, a sealed single plastic bag with 50 mL of water within a sealed outer plastic bag. The last three test samples were given three-level containment, a sealed single plastic bag with 50 mL of water within a sealed inner plastic bag sealed in an outer plastic bag. One test sample of each level of containment was placed around the University of Toronto Scarborough campus for 5 weeks. Test samples

T1, T4 and T5 were placed in the University of Toronto Scarborough campus soil laboratory, Science Wing Room 313, to simulate water loss over the given period. Test

44 samples T2, T6 and T9 were placed in Science Wing Room 653, to simulate water loss over the given period in a faculty office setting. Test samples T3, T7 and T8 were placed in University of Toronto Scarborough Foley Hall Residence, to simulate water loss over the given period in a storage setting. After the 5 weeks, the mass of the test samples,

M5wks, were determined using the electronic mass balance.

The change in mass water, ΔMw, difference could be calculated from:

[(M5wks)-(Mbw)] = (ΔMw), (20)

To convert the change in mass water, in grams, to a volume loss, Vloss, in millilitres, the density of water at 23ºCelsius (0.9975 g/mL) can be used:

[(ΔMw) (g)/ (0.9975 g/mL)] = (Vloss). (21)

To finally determine the percentage of water lost, WL%, after five weeks, the following can be applied:

[(Vloss)/(Vw)]*100 = (WL%). (22)

3.4 Stefan Depths and Permafrost Table Calculations

The Stefan depths were determined using Equation 3. The depth to permafrost, d, were extracted from field notes and data provided by Gough. Average depths to permafrost were calculated using the collected field data on permafrost depth with an arithmetic average approach. When the calculated seasonal Stefan depth of freezing exceeds the seasonal Stefan depth of thawing (Du < Df), the resulting positive thermal offset represents the theoretical thickness of a frozen layer of soil that has persisted over the summer thawing season, and has survived into the next freezing cycle (Burns &

45 Smith, 1987; Duan & Naterer, 2009). When the thermal offset conditions of Df < Du, there is a loss of frozen ground at the frost table (Burns & Smith, 1987).

3.5 Thawing and Freezing Degree-Days Calculations

Thawing and freezing degree-days (TDD, FDD, respectively) were calculated using temperature data collected from the weather station in Peawanuck, Ontario. The temperature data prior to 1986 were collected from the Winisk, Ontario weather station.

Following the destruction of Winisk and the relocation of the community to Peawanuck in 1986, all temperature data after 1986 were obtained from the present day weather station Peawanuck (AUT). In calculating thawing degree-days, the cumulative number of days above 0ºC was counted for a single year record. For the freezing degree-days, the cumulative count of the number of days below 0ºC was counted for a single year interval.

For a one-year interval, this calculation requires 12 months of temperature data. Twelve month was chosen from the beginning of July from the previous year to the end of June of the next year. A thawing degree-day calculation example for the year of 1992 would be to count the number of days above 0ºC starting from July 1st of 1991 ending on June

30th of 1992 and then determine the sum of the number of count of days above 0ºC. This was repeated for calculating freezing degree-days.

46 3.6 Geographical Information Systems

Geographical Information Systems (GIS) was used to produce a geographical map of the sampling area based on degree-decimal location coordinates. The location coordinated were geo-reference using hand held Global Positioning Satellite (GPS) device conducted by personnel from the Ontario Ministry of Natural Resources. A map of the Hudson Bay region was also produced in GIS Manifold System software version 8 and drawings from ESRI Data and Maps Volume One. The Universal Transverse

Mercator (UTM) coordinate system was applied as the map projection. UTM zones 16 and 17 were utilized for the GIS map projection. GIS was used to extract distances from the sample sites to the nearest shore of Hudson Bay using the query function and the software reported distances in units of metres.

47 CHAPTER 4: Results

4.1 Climate and Environmental Data

Both climate and environmental data were collected for the Fort Severn and

Peawanuck, Ontario, sites. The mean annual precipitation for the Hudson Bay lowlands was determined to range from 401 to 600 millimeters (Natural Resources Canada, 2006).

The mean maximum snow depth in the Hudson Bay lowlands was determined to range from 30-49 centimetres (Natural Resources Canada, 2006). The subsurface stratigraphy of Fort Severn and Peawanuck is continuous permafrost (Figure 10; Natural Resources

Canada, 2006).

Figure 10 – Subsurface stratigraphy classification of Northern Ontario and Hudson Bay by Natural Resources Canada (Natural Resources Canada, 2006)

48 A summary of the minimum and maximum winter (January) and summer (July) daily temperatures for Fort Severn and Peawanuck are shown in Table 3.

Table 3 – Results: Elevation and Annual Temperature Ranges in Northern Ontario communities from Environment Canada. (Environment Canada, 2009a; Environment Canada, 2009b). Location Relief Minimum Maximum Minimum Maximum Elevation Daily January Daily July Daily July (metre) January Daily Temperature Temperat Temperature Temperature – Summer ure – – Winter – Winter (ºC) (ºC) Summer (ºC) (ºC) Fort Severn 15.80 m -34 to -30 -24 to -20 6 to 10 16 to 20 Peawanuck 52.70 m -29 to -25 -24 to -20 6 to 10 16 to 20

4.2 Soil Characterization (2007-2008)

Using GIS software and GPS coordinates for the sample sites recorded in the field notes, Figures 5 to 7 were produced to include sample site locations from the shore of

Hudson Bay to approximately 100 kilometers inland.

Soil characteristics of the retrieved soil samples and over 500 site observations revealed soils of the Cryosols and Histosols orders which typically have permafrost presence within the first two-metres in depth (Juma, 2006). Site descriptions from the field notes revealed extensive peat formations and organic matter content in the poorly drained soils. Further laboratory analyses of the soil samples are shown in Table 6.

Distances from the sampled sites to the nearest shore of Hudson Bay were extracted to

Tables 4 and 5. The results of soil characterizations from August 2007 and 2008 are shown in Tables 4 and 5, respectively. There were 20 sites and soil characterizations for

2007 and 33 for 2008 totaling 53 characterizations during the two-year sampling campaign (Tables 4 and 5).

49 Table 4 – Results: Site & Soil Characterizations from 2007 Soil Sampling Campaign with Distances from the Shores of Hudson Bay to the Sample Sites. Distance to Sample Hudson Bay ID Latitude Longitude (m) Site & Soil Characteristics Site was heavily vegetated. Soil sample was aggregated with the presence of organic matter (woody stems, roots and moss). Sample appeared light brown/gray colour and a gritty clay texture. No detectable B1 55°15.405 -85°12.394 10000 odour. Situated in grassy vegetation. Some aggregation present in soil sample. Presence of organic matter (fine roots). Sample appeared light brown in colour, clayey texture with moderate moisture. Gravel was present at 100 cm depth. No detectable B2 55°20.032 -85°27.129 9341 odour. Soil sample was not well aggregated. Presence of organic matter (fine roots) with high moisture content. Soil appeared dark- brown colour. Presence of gravel. Strong B3 55°20.032 -85°25.673 8134 musky odour. Sample site located on a palsa. Hummocky Tundra terrain with the presence of a "baby palsa." Presence of organic matter (partial decaying grasses and fibrous roots). Soil sample was well aggregated and dry. No B4 55°11.745 -85°39.212 29136 detectable odour. Presence of organic matter (twigs). Mostly decomposing plant organic material. Soil appeared dark and very moist. No detectable odour. Soil contained presence of B5 55°02.865 -85°51.121 49826 three miniscule worm-like organisms. Site was situated on a palsa adjacent to a pond. Other ponds were observed in the area. Sample was well aggregated with high organic matter content. Soil sample had presence of organic matter (fine roots). No B6 54°56.772 -86°06.884 69600 detectable odour.

50 Site was located in a vegetated fen near a palsa (15-20 metres wide). A dried mudflat south of the palsa was observed adjacent to the sampling site. An area with trees is located 20 metres to the north of the palsa. Presence of organic matter (decomposing leaves, stems, and pod husks). Husks appeared white internally and dark brown externally. Soil colour appeared dark brown with organic matter and very moist conditions. Presence of fine sediments. No C2c 55°04.860 -84°15.321 21258 detectable odour. Sample site was located on a steep terrain adjacent to a palsa and ponds with adjacent trees. Soil colour appeared light brown. Presence of organic matter (peat, fungus, molds, and roots). The soil sample was dry. C3 54°54.146 -84°10.322 41836 No detectable odour. Sample site was located on the coast of Hudson Bay in a fen at the north aspect of a coastal ridge. Willows were observed at the site. There was presence of organic matter (moss and fibrous roots with a spongy texture). Sample appeared dark brown in colour and dry. Presence of fine particulate matter with weathered and rounded pebbles that appeared white & black. Gravel was observed at a depth of 10 cm. No detectable C8 55°16.289 -83°50.593 500 odour. Sample site was located at the centre of a palsa plateau. Adjacent area to the east was relatively treeless. Palsa fens are located to the south, west and north of the sample site. Palsa centre was 90 cm in height. A new palsa formation was observed (3 m wide by 20 m long) and dark in appearance to the north. Presence of organic matter (dense fibrous roots, decaying leaves, fungus, moss and mold). Sample had a clayey texture. No D1 54°56.873 -83°46.804 31719 detectable odour

51 Sample site was located at the centre of a palsa surrounded by a moat. Standing water was present to the east, west and northern edges. Soil samples showed presence of organic matter (woody stems, roots, leaf litter, and dark-brown coloured peat). Moderate moisture content. No detectable D2 55°06.382 -83°48.716 15233 odour. Sample site was located 3 m into a fen. Soil sample showed presence of organic matter (fibrous roots, decaying plant matter, leaf litter, and fungus with a spongy texture). D4l 55°00.503 -83°12.043 21606 The sample was moist. No detectable odour. Sample site was located on a coastal plain with the presence of trees. Samples were retrieved from a central palsa. Presence of organic matter (white moss, fungi, partial decaying grass, twigs, woody stems, and roots). The sample appeared light brown in colour. There was presence of weathered D5a 54°50.442 -83°03.364 31420 and rounded pebbles. No detectable odour. Sample site was located at the centre of a palsa. Standing water was observed to the northern edge of the palsa. A 1-metre depression with standing water in the palsa was speculated as a thaw slump. Presence of organic matter (long fibrous roots, plant stems, peat and decomposing organic E1 56°21.871 -89°30.534 64315 matter). No detectable odour. Sample site was located 25 m in a fen and on a 0.5 m tall palsa. Presence of organic matter (decaying bark and twigs). Soil sample appeared to have a sandy and grainy texture that had a light reddish-orange E2 56°30.401 -89°18.550 44307 colour. No detectable odour. Sample site was located 1 m from the southern edge of a fen. Presence of organic matter (roots, grasses, decaying bark, leaves and twigs). Soil sample appeared light E2a 56°30.401 -89°18.550 44307 brown in colour. No detectable odour.

52 Sample site was located in hummocky lichen woodland with a large palsa plateau. Forested area was well developed. Presence of soil organic matter (roots, stems, and peat). Presence of weathered and rounded black pebbles. The soil appeared light brownish-yellow colour with an orange horizon. The soil had a sandy texture. No E6 56°26.585 -88°36.857 21074 detectable odour. Sample site was located in a dried fen with gravel edges. Samples were taken 2.5, 5 and 10 metres into the fen. Soil samples showed presence of organic matter (dense root networks with a spongy characteristic, grasses, leaves, and woody stems). Soil had an overall dark-brown colour. Sample had a presence of fine sediments. Clayey soil was observed in the sample site. Strong foul E10 56°22.395 -87°54.609 500 odour was present. Sample site was located 2 km from the Hudson Bay coast on a beach ridge. Presence of organic matter (decaying thick root systems). Sample contained rocks and pebbles. Soil colour appeared to have a mixture of dark & light shades of brown. Sample was dry and had a sandy texture. F8 55°13.126 -84°41.726 2046 No detectable odour. The sample site was in a fen field at the centre of an emerging palsa. Soil sample contained presence of organic matter (dense roots, white mold, decaying twigs and grasses). Soil was primarily organic matter. G5a 55°41.102 -86°51.325 21289 No detectable odour.

Table 5 – Results: Site & Soil Characterizations from 2008 Soil Sampling Campaign with Distances from the Shores of Hudson Bay to the Sample Sites. Sample Distance to ID Latitude Longitude Location Coast (m) Soil & Site Characteristics Sampling at Burnt Point near a fence post in a fen. Presence of sand with round weathered gravel. Gravel had white and black colours. No organic matter content was observed. Sandy and 8A1 55°14.507 -84°19.002 Coastal 2842 silty soil texture. No detectable

53 odour. Whales were observed in Hudson Bay from this location.

Sample site was located to the north of a grass area on a beach ridge near a fen along the coast. Site had high moisture content. Sandy and clayey soils were observed with weathered pebbles. No organic matter content was 8A2 55°36.618 -85°48.648 Coastal 367 observed. No detectable odour. Sample site was dominated by a hummocky palsa with an emerging palsa to the west. Peat and moss were observed at the 8A3 55°27.630 -85°58.379 Inland 19329 site. No detectable odour. Sample site was located on a beach ridge. High soil moisture content. Gravelly soil texture. Rounded and weathered gravel stones with black and white colours. No organic matter content was observed. No detectable odour. A polar bear 8B1 55°28.982 -85°59.529 Inland 18421 was observed. Sample site was located on a beach ridge near the coast. Site had high moisture content. Sandy soil was observed in the upper 10 cm with weathered pebbles. Gravelly soil was observed at a depth of 2 m. No organic matter content was observed. No 8B2 55°52.162 -86°47.037 Coastal 90 detectable odour. Sample site was located on a beach ridge near the coast and a fen. Sandy and clayey soil textures were noted. Site had high moisture content. No organic matter content was observed. No 8B3 55°55.436 -87°11.034 Coastal 940 detectable odour.

54 Adjacent to 2007 site “E10”. Sample site was located on a beach ridge and near a fen. A few trees were noted in the area. Soil from the beach ridge was sandy and gravelly with weathered pebbles. Soil from the beach ridge had high soil moisture content. Soil from the fen was dominantly clayey. Whales and a mink were observed in the area. No 8B4 56°22.281 -87°54.601 Coastal 500 detectable odour. Adjacent to 2007 site “C8”. Sample site was located on a beach ridge near the south of a fen. High soil moisture content. Soil in the beach ridge had a gravelly soil texture. Soil in the fen was dominantly clayey. No 8C1 55°16.296 -83°50.592 Coastal 655 detectable odour. The site had shrub vegetation without any tall trees and located on a beach ridge. Site had high moisture content with ponds and large puddles. Clay soil was detected under an upper peat layer. Below the clay soil, sandy soil was observed. No detectable odour. A Greater Yellow Leg was 8C2 55°11.730 -83°17.420 Coastal 1468 observed in the area. Sample site was located on a beach ridge dominated with grasses and shrubs. No trees were in the area. Surface soils had a gravelly and sandy texture with black and white pebbles. Site had high soil moisture content. No 8C3 55°12.499 -82°57.808 Coastal 1339 detectable odour. Site was located on a beach ridge dominated by gravelly and sandy soils. No presence of organic matter. Site had high soil moisture content. No odour 8C4 55°02.715 -82°51.658 Coastal 8765 detected. Site was located at the shores of 8C5 54°48.174 -82°12.008 Coastal 85 James Bay on sandy dunes and

55 beach known as Hook Point. Site was moderately vegetated dominated in sandy soils. Site had high soil moisture content. No detectable odour. Site was located on a beach ridge near a palsa and fen. The surface was dominated in peat. Weathered and rounded gravel were observed at the surface. Soil below the gravel was clayey. Site had high soil moisture content. No detectable odour. An eagle 8D1 55°43.908 -86°29.256 Coastal 6388 nest was observed in the area. Site was located on a beach ridge near a fen. Trees were observed in the fen. Surface soil was dominantly sandy and clayey. Wet gravel was observed at 8D2 56°25.104 -88°09.957 Coastal 7631 greater depths. Sample site was located on a beach ridge near a fen. Clayey and sandy soils were observed near the fen with pebbles. No 8D3 56°35.560 -88°25.510 Coastal 560 detectable odour. Site was located on a beach ridge dominated by sandy and clayey soils. Site had high soil moisture 8D4 56°47.266 -88°57.621 Coastal 5680 content. No detectable odour. Adjacent to 2007 site “E6”. Site 8D5 56°26.550 -88°36.048 Inland 21074 was located in lichen woodland. Site was located on a palsa plateau dominated in peat. Some trees were observed in the area and remnants of a fen. The site had high soil moisture content with the presence of bogs. Clayey soil was observed below the peat 8E1 55°37.780 -87°33.988 Inland 37800 layer. No detectable odour. Site was located in lichen woodland with a pond to the southwest. Low trees and shrubs were observed in the area. Site had high moisture content. No 8E2 55°31.322 -86°58.361 Inland 39841 detectable odour. 8E3 55°41.111 -86°51.326 Inland 21289 Adjacent to 2007 site “G5a”. Site

56 was located on a palsa with an emerging palsa nearby and surrounded by a fen. The site has low vegetations and no trees. Site had high soil moisture content. Nearby fuel barrel cache was damaged due to vandalism. Site was located near Winisk, Ontario, near the coast. Site was well vegetated by grass. Surface soil layer was dominated by organic material underlain by 8E4 55°15.623 -85°12.639 Coastal 50 clay. No detectable odour. Site was located in a fen dominated by lichen. Presence of an old palsa was observed. Soil 8F1 55°46.94 -87°22.559 Inland 17663 had high moisture content. Site located in lichen wooden. Site was observed to have been a burned area with some surviving trees. Gravel was observed at a 8F2 55°30.075 -86°36.199 Inland 30768 depth of 45 cm. Adjacent to 2007 site “F8”. Site was located on a beach ridge dominated by sandy and clayey soils. Gravelly soils were observed below the surface layer. Site had high soil moisture 8G1 55°13.124 -84°41.727 Coastal 2040 content. No detectable odour. Site was located in a shallow Polar Bear den on a ridge of hummocky organic material. Sedges and low growth vegetable 8G2 55°02.797 -83°06.238 Inland 12407 was observed in the area. Site was located in a Polar Bear den and 20 metres from a beach ridge and fen. Sandy soil was observed at the site. Standing water was observed at the fen. A Boreal Chorus Frog (Pseudacris maculata) was identified at the 8G3 55°02.541 -83°04.724 Inland 11151 site. Hummocky surface soil was dominated by sphagnum. Clayey soil was observed below the 8G4 54°38.784 -83°03.361 Inland 53321 organic layer. Soil had high

57 moisture content. Site was located in lichen woodland on a ridge. Clayey soil was observed at the site. Bird nest was observed to the south of the ridge. Polar Bear tracks and a hole possibly excavated by a Polar Bear were observed. Soil 8H1 54°42.897 -84°06.587 Inland 58298 had moderate moisture content.

4.3 Laboratory Analysis Results (2007-2008)

4.3.1 Soil Moisture Content and Soil Acidity

The results from the laboratory analysis work were completed on October 4th of

2007 for the gravimetric soil moisture content and soil acidity from the samples retrieved from Northern Ontario and Hudson Bay (Figure 6). The gravimetric soil moisture content and soil acidity results are summarized in Table 6.

Table 6 – Results: 2007 Laboratory Analysis for Gravimetric Soil Moisture Content and Acidity for Northern Ontario Results: Northern Ontario - August 2007 Gravimetric Sample Soil Moisture Identification Content Soil Acidity SID θm (%) pH Average B1 31.9 7.09 B2 63.2 6.90 B3 93.9 6.02 B4 72.0 5.75 B5 94.0 5.95 B6 73.2 3.71 C2c 92.7 5.40 C3 71.9 4.16 C8 22.9 6.06 D1 81.6 4.24 D2 78.8 4.75 D4l 92.5 6.06 D5a 81.1 3.99 E1 31.1 3.50

58 E10 94.2 6.06 E2 10.2 6.84 E2a 56.1 5.47 E6 5.6 5.79 F8 28.6 5.79 G5a 76.9 5.34

The majority of the samples was composed of organic material such as peat or soils with fibrous roots and partially decomposed moss. The overall results showed high soil moisture condition in which eighteen (18) of the twenty (20) samples had gravimetric soil moisture content, θm, greater than 20% (Table 6). Fourteen (14) of the 20 samples had gravimetric soil moisture content, θm, greater than 50% soil moisture content (Table

6). The samples were acidic overall with a mean pH of 4.41 (STD = 1.06; Table 6).

Average pH was calculated using the methodology outlined in 3.3.4 Soil Acidity,

Average pH Value.

The samples from the 2008 soil-sampling campaign were analyzed on October

27th of 2008 for the gravimetric soil moisture content and soil acidity from the samples retrieved from Northern Ontario and Hudson Bay (Tables 7 & 8). The analysis and results were divided based on coastal and inland regions of the sample area (Figure 7).

The results are shown in Tables 7 & 8.

The results from the analysis of the twenty-three (23) coastal samples along

Hudson Bay showed drier gravimetric soil moisture, θm, conditions in which twenty-two

(22) of the 23 samples were less than 30% soil moisture content (Table 7). Fourteen (14) of the 23 samples had soil moisture contents greater than 10% soil moisture content and only three (3) of the 23 samples had soil moisture contents greater than 20% soil moisture content (Table 7). The highest coastal soil moisture content was 37.5% at site 8C2 in

59 2008 (Table 7). The mean pH for the coastal samples was 7.14, slightly basic (STD =

0.05; Table 7).

Table 7 – Results: 2008 Laboratory Analysis for Gravimetric Soil Moisture Content and Acidity for Sampling Sites along the Shores of Hudson Bay. Results: Shores of Hudson Bay - August 2008 Gravimetric Sample Soil Moisture Identification Content Soil Acidity SID θm (%) pH Average 8A1 15 7.1 7.11 8A1 30 5.7 7.10 8A1 65 5.5 7.15 8A1 120 14.2 7.14 8A2 9.3 7.12 8A2 18 25.7 7.18 8B1 6.6 7.17 8B2 8.6 7.07 8B3 12.6 7.13 8B4 10 10.0 7.17 8B4 PF 15.6 7.18 8C1 12.6 7.08 8C2 37.5 7.09 8C3 9.7 7.09 8C4 10.1 7.08 8C4 137 15.4 7.18 8C5 7.6 7.33 8D2 15.9 7.12 8D3 10.8 7.08 8D4 20.1 7.17 8G1 0 9.4 7.15 8G1 116 16.4 7.15 8G1 PF 14.9 7.17

Results from the analysis of the ten (10) inland soil samples from Northern

Ontario showed higher soil moisture content, θm, conditions in which six (6) of the 10 soil samples were greater than 20% soil moisture content and only two (2) of 10 samples with less than 15% soil moisture content (Table 8).

60 Table 8 – Results: 2008 Laboratory Analysis for Gravimetric Soil Moisture Content and Acidity for Sampling Sites inland in Northern Ontario. Results: Inland Northern Ontario - August 2008 Gravimetric Sample Soil Moisture Identification Content Soil Acidity SID θm (%) pH Average 8D5 6.5 7.02 8E1d 21.5 7.39 8E2a 91.0 6.00 8F1a 92.1 6.76 8F2a 12.5 7.14 8F4a 47.4 7.09 8G4a160 19.4 7.50 8G4asfc 95.4 5.37 8H1a10 77.1 6.00 8H1a100 18.5 7.48

The mean pH for the inland samples was 6.17, therefore slightly acidic (Table 8). The highest inland soil moisture content value was 95.4% at site 8G4 in 2008 (Table 8).

4.3.2 Measured Depths to Permafrost

Point-scale depths to permafrost were measured at twenty (20) sites along the shores of Hudson Bay and inland in Northern Ontario using a graded rod (Figure 6). This was conducted in August of 2007; the results for the depths to permafrost and the location of each sample site in the designated quadrants are shown in Table 9.

61 Table 9 – Results: Depths to Permafrost for 2007 Sampling Site and Classified by Quadrants

Average Depths to Sample Permafrost Quadrant ID (cm) on Map B1 68 2 B2 N/A 2 B3 N/A 2 B4 35 2 B5 N/A 2 B6 37.5 2 C2c 39 3 C3 47 3 C8 10 3 D1 52 3 D2 42 3 D4l 86 3 D5a 37 3 E1 49 1 E10 58 1 E2 33 1 E2a 40 1 E6 N/A 1 F8 52 3 G5a 48 2

In August of 2008, point-scale depths to permafrost were measured at twenty-eight (28) sites along the shores of Hudson Bay and inland in Northern Ontario using a graded rod

(Figure 7). Depth to permafrost was confirmed using a thermistor probe to determine the minimum and mean soil temperatures. The results of the mean depths to permafrost, soil temperatures and the location of each sample site in the designated quadrants are shown in Table 10.

62 Table 10 – Results: Depths to Permafrost for 2008 Sampling Site and Classified by Quadrants Average Site Soil Site Soil Sample Average Site Depth to Temperature Temperature Quadrant ID permafrost (cm) (ºC) (min ºC) on Map 8A1 119.67 5.27 1.82 3 8A2 125.5 3.56 1.58 2 8A3 48.17 1.1 0.14 2 8B1 108 1.9 1.9 2 8B2 85 1.83 1.58 2 8B3 114.5 0.9 0.9 2 8B4 96.25 1.47 1.47 1 8C1 110.75 2.07 1.26 3 8C2 95 8.2 8.2 3 8C3 93 5.58 4.96 3 8C4 99 4.31 3.19 3 8C5 182 1.77 1.77 3 8D1 39 0 0 2 8D2 149.5 3.98 2.01 1 8D3 99 0.46 0 1 8D4 142 0.09 0.09 1 8D5 175 10.5 10.5 1 8E1 140.8 1.11 0.29 2 8E2 256 2.6 2.6 2 8E3 83.82 0.96 0.18 2 8E4 193.5 5.38 5.17 2 8F1 145.67 6.6 4.86 2 8F2 175 10.87 10.87 2 8G1 140.5 0.72 0.48 3 8G2 49.89 0.65 0.23 3 8G3 53.71 2.87 0.87 3 8G4 147.67 2.62 2.36 3 8H1 166 2.96 2.39 3

The mean depths to permafrost were calculated from Tables 9 & 10 according to the map quadrants where each site was located and the results are shown in Table 11.

63 Table 11 – Results: Yearly Average Depths to Permafrost per Quadrant Average Depths to Permafrost (cm) Year Quadrant on Map --- 1 2 3 2007 45.0 47.13 45.63 2008 132.35 126.25 114.29

4.4 Freezing and Thawing Degree-Days (1989-2007)

4.4.1 Results from 1989 to 2002

The freezing and thawing degree-days from 1989 to 2002 were calculated from temperature data collected from the northern community weather station at Peawanuck,

Ontario. The results are shown in Figures 11 and 12 and the statistical data were shown in

Tables 12 and 13.

Results: Peawanuck Degree Days (1989 - 2002)

2000 1800 1600 1400 1200 1000

800 Degree Days Degree 600 400 200 0 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

Thawing Degree Days Freezing Degree Days

Figure 11 – Results: Freezing and thawing degree-days for Peawanuck, Ontario, from 1989-2002

The thawing degree-days appear to have generally increased between the years of

1989 to 2002 with slight decreases in 1992, 1995, 2000 and 2002; test of significance using regression analysis with a 95% confidence interval was performed, and the p-value of 0.106 suggests that the observed trend is not statistically significant (R2 = 0.216; r =

0.465; Figure 11; Table 12).

Table 12 – Results: Statistical Analysis of the 1989 – 2002 Peawanuck Degree-Days Peawanuck Degree Days Thawing Freezing 1989 - 2002 Degree Days Degree Days STD 164 297 MEAN 1433 1192 R2 0.216 0.660 p-value (95% CI) 0.106 0.000

The peak thawing degree occurred in 2001 at 1798 thawing degree-days. The freezing degree-days appear to have generally decreased between the years of 1989 to 2002; test of significance using regression analysis with a 95% confidence interval was performed, and the p-value of 0.000 suggests that the observed trend is statistically significant (R2 =

0.660, r = -0.812; Figure 11; Table 12). From 1989 to 2000, the number of freezing degree days decreased from 1614 to 557 freezing degree-days (Figure 11). There was an increase in freezing degree-day from 2000 to 2001, 557 to 1105 freezing degree-days respectively (Figure 11). As shown in Figure 11, the number of freezing degree days per year in the late 1980s and early 1990s exceeded the number of thawing degree-days for the same year. From 1993 onwards, the thawing degree-days per year exceed the freezing degree-days per year. As the thawing degree-days in Peawanuck increased, there was a decrease in the freezing degree-days.

65 4.4.2 Results from 2004 to 2007

The freezing and thawing degree-days from 2004 to 2007 were calculated from temperature data collected from the Peawanuck weather station (Figure 12).

Results: Peawanuck Degree Days (2004 - 2007)

2000 1751 1800 1718 1659 1600 1439 1400 1232 1200 1025 1054 1000

800 722 Degree Days 600 400 200 0 2004 2005 2006 2007 Year

Thawing Degree Days Freezing Degree Days

Figure 12 – Results: Freezing and thawing degree-days for Peawanuck, Ontario, from 2004-2007

The thawing degree-days appear to have generally increased between the years of

2004 (1025 thawing degree days) to 2007 (1659 thawing degree days) with a peak increase in 2005 at 1751 thawing degree-days; test of significance using regression analysis with a 95% confidence interval was performed, and the p-value of 0.301 suggests that the observed trend is not statistically significant (R2 = 0.491; r = 0.701;

Figure 12; Table 13).

66 Table 13 – Results: Statistical Analysis of the 2004 - 2007 Peawanuck Degree-Days Peawanuck Degree Days Thawing Freezing 2004 - 2007 Degree Days Degree Days STD 345 303 MEAN 1538 1112 R2 0.491 0.006 p-value (95% CI) 0.301 0.920

The freezing degree-days appear to have slightly increased between the years of

2004 (1054 freezing degree day) to 2007 (1232 freezing degree days) with a peak decrease in 2006 at 722 freezing degree-days; test of significance using regression analysis with a 95% confidence interval was performed, and the p-value of 0.920 suggests that the observed trend is not statistically significant (R2 = 0.006, r = 0.077;

Figure 12; Table 13). As shown in Figure 12, in 2004, freezing degree-days per year exceeded the thawing degree-days per year, and, by 2005, the thawing degree-days per year had exceeded the freezing degree-days.

Statistical regression analysis, using 95% confidence interval, was performed for the entire 1987 to 2007 (excluding 2003) degree-days. Regression analysis for the thawing degree-days from 1989 to 2007 (excluding 2003) had a p-value of 0.101 suggesting the trend was not statistically significant, with standard deviation of 195.552 and R2 value of 0.173. Regression analysis using 95% confidence interval showed that freezing degree-days from 1989 to 2007 (excluding 2003) had a p-value of 0.014 suggesting that the trend is statistically significant, with standard deviation of 248.453 and R2 value of 0.314. Overall, the number of thawing degree days did not change

67 significantly between 1987 and 2007 whereas there was a significant decrease in the number of freezing degree days over the same period.

4.5 Stefan Depth and Permafrost Table Results (1989-2007)

The Stefan depth to the permafrost table and thermal offset were calculated using the degree-days from Figures 11 & 12 with Equations 4, 5, 6 and 7 for the periods between 1989 to 2002 and 2004 to 2007. The Stefan depth for freezing, Df, and thawing,

Du, layers were used to calculate the thermal offset in determining the permafrost state.

Various soil thermal conductivity (λ) values for various substrates dominating Arctic soils were considered in calculating the results, such as sand (porous, non-porous), clay and peat soils. The soil thermal conductivities of Du (λu) reflect dry theoretical summer conditions of 0% soil moisture content, representing a lesser thermal offset effect (Figure

13; Nixon & McRoberts, 1973). The soil thermal conductivities of Df (λf) were adjusted by 1.5 times the values of Du to represent the thermal offset effect of moist soils of 20% soil moisture content (Figure 13; Nixon & McRoberts, 1973; Kujala et al., 2007).

Figure 13 - Thermal conductivity to water content for fine-grained soils, both frozen and thawed soils (Nixon & McRoberts, 1973).

Since palsas have more organic matter and higher soil moisture content (30% soil moisture content), the soil thermal conductivity was adjusted by 1.75 times the dry value to represent an enhanced thermal offset effect (Figure 13; Nixon & McRoberts, 1973;

Kujala et al., 2007).

69 4.5.1 Porous Sandy Soils (1989 to 2007)

For Arctic soils dominated by porous sand (porosity >0.33) and given the degree- day conditions from Figures 11 and 12 from 1989 to 2007, the thermal offset results were calculated from the Stefan depths using Equations 4, 5, 6 and 7 (Figure 14 & Table 14).

Thermal Offset in Sand (Porosity >0.33) 1989 - 2007

0.500 0.400 0.300 0.200 0.100 0.000 -0.1001988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 -0.200

Thermal Offset Df - Du (m) -0.300 -0.400 Year

Thermal Offset Df - Du (m)

Figure 14 – Thermal Offset for Sand (Porosity >0.33) Compositions 1989-2007

Table 14 – Results: Stefan Depths for Porous Sand (Porosity >0.33) Soil Compositions (1989-2002) Stefan Depth - Permafrost Table (1989 - 2002) Sand (Porosity >0.33) λ(F) = 1.99x1.5, λ(U) = 1.99 Thermal Offset Year Df (m) Du (m) Df - Du (m) 1989 1.579 1.157 0.422 1990 1.551 1.184 0.368 1991 1.486 1.231 0.255 1992 1.438 1.091 0.347 1993 1.419 1.198 0.221 1994 1.434 1.239 0.194 1995 1.354 1.147 0.207 1996 1.461 1.217 0.244 1997 1.328 1.243 0.085 1998 1.109 1.309 -0.200 1999 1.166 1.258 -0.092

70 2000 0.927 1.176 -0.249 2001 1.306 1.360 -0.054 2002 1.277 1.171 0.106

From 1989 to 1997, the depth of annual freezing of Arctic soils dominated by porous sand generally exceeded the depth of annual thawing leading to a positive thermal offset value (Table 14). This favoured permafrost conditions to freezing, interannual accumulation, by a mean of 0.260 metres (STD = 0.103) over the 9-year span (Table 14).

After 1998, the depth of annual thawing exceeded the depth of annual freezing leading to a negative thermal offset value, permafrost unfavorable conditions, by a maximum of 0.249 metres of thawing in 2000 in arctic soils dominated by porous sand

(Table 14).

For Arctic soils dominated by porous sand from 2004 to 2007 and given the degree-day conditions from Figure 12, the thermal offset results showed depth of annual freezing of Arctic soils dominated by porous sand generally exceeded the depth of annual thawing leading to a positive thermal offset value (Table 15).

Table 15 - Results: Stefan Depths for Porous Sand (Porosity >0.33) Soil Compositions (2004-2007) Stefan Depth - Permafrost Table (2004 - 2007) Sand (Porosity >0.33) λ(F) = 1.99x1.5, λ(U) = 1.99 Thermal Offset Year Df (m) Du (m) Df - Du (m) 2004 1.276 1.027 0.249 2005 1.490 1.343 0.148 2006 1.056 1.330 -0.274 2007 1.379 1.307 0.072

This favoured permafrost conditions for freezing by a mean of 0.49 metres (STD

= 0.227) over 4 years from 2004 (Table 15). In 2006 and onwards, the depth of annual

71 thawing exceeded the depth of annual freezing leading to a negative thermal offset value, loss of permafrost, of 0.274 meters of thawing in porous sandy arctic soils (Table 15).

4.5.2 Non Porous Sandy Soils (1989 to 2007)

In Arctic soils dominated by non-porous sand (porosity <0.33) and given the degree-day conditions from Figures 11 and 12 from 1989 to 2007, the thermal offset results were calculated using Stefan depths and Equations 4, 5, 6 and 7 (Figure 15; Table

16).

Thermal Offset in Sand (Porosity <0.33) 1989 - 2007

0.400

0.300

0.200

0.100

0.000 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 -0.100

-0.200 Thermal Offset Df - Du (m) -0.300 Year

Thermal Offset Df - Du (m)

Figure 15 – Thermal Offset for Sand (Porosity <0.33) Compositions 1989-2007

72 Table 16 – Results: Stefan Depths for Non-Porous Sand (Porosity <0.33) Soil Compositions (1989- 2002) Stefan Depth - Permafrost Table (1989 - 2002) Sand (Porosity <0.33) λ(F) = 0.787x1.5, λ(U) = 0.787 Thermal Offset Year Df (m) Du (m) Df - Du (m) 1989 0.993 0.728 0.265 1990 0.976 0.744 0.231 1991 0.934 0.774 0.160 1992 0.905 0.686 0.218 1993 0.892 0.753 0.139 1994 0.902 0.779 0.122 1995 0.852 0.721 0.130 1996 0.919 0.765 0.153 1997 0.835 0.781 0.054 1998 0.697 0.823 -0.126 1999 0.733 0.791 -0.058 2000 0.583 0.740 -0.157 2001 0.821 0.856 -0.034 2002 0.803 0.737 0.067

From 1989 to 1997, the depth of annual freezing of non-porous sandy arctic soils generally exceeded the depth of annual thawing leading to a positive thermal offset value

(Table 16). This favoured permafrost conditions to freezing, interannual accumulation, by a mean of 0.164 metres (STD = 0.065) over the 9-year span (Table 16).

After 1998, the depth of annual thawing exceeded the depth of annual freezing leading to a negative thermal offset value, permafrost unfavorable conditions, by a maximum of 0.157 metres of thawing in 2000 in non-porous sandy soils (Table 16).

For arctic non-porous sandy soils and given the degree-day conditions from

Figure 12 from 2004 to 2007, the thermal offset results showed depth of annual freezing generally exceeded the depth of annual thawing leading to a positive thermal offset value

(Table 17).

73 Table 17 – Results: Stefan Depths for Non-Porous Sand (Porosity >0.33) Soil Compositions (2004- 2007) Stefan Depth - Permafrost Table (2004 - 2007) Sand (Porosity <0.33) λ(F) = 0.787x1.5, λ(U) = 0.787 Thermal Offset Year Df (m) Du (m) Df - Du (m) 2004 0.802 0.646 0.157 2005 0.937 0.844 0.093 2006 0.664 0.836 -0.172 2007 0.867 0.822 0.045

This favoured permafrost condition to freezing by a mean of 0.031 metres (STD = 0.143) over the four years (Table 17).

In 2006, the depth of annual thawing of Arctic soils dominated by non-porous sand exceeded the depth of annual freezing led to a negative thermal offset value, loss of permafrost, of 0.172 meters of thawing (Table 17).

4.5.3 Clay Soils (1989 to 2007)

For Arctic soils dominated by clay and given the degree day conditions from

Figure 11 from 1989 to 2002, the thermal offset results were calculated using Equations

4, 5, 6 and 7 (Figure 16; Table 18).

74 Thermal Offset in Clay 1989 - 2007

0.300 0.250 0.200 0.150 0.100 0.050 0.000 -0.0501988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 -0.100

Thermal Offset Df - Du (m) -0.150 -0.200 Year

Thermal Offset Df - Du (m)

Figure 16 – Thermal offset for Clay Compositions 1989-2007

Table 18 – Results: Stephan Depths for Clay Soil Compositions (1989-2002) Stefan Depth - Permafrost Table (1989 - 2002) Clay λ(F) = 0.755x1.5, λ(U) = 0.755 Thermal Offset Year Df (m) Du (m) Df - Du (m) 1989 0.972 0.713 0.260 1990 0.956 0.729 0.226 1991 0.915 0.758 0.157 1992 0.886 0.672 0.214 1993 0.874 0.738 0.136 1994 0.883 0.763 0.120 1995 0.834 0.707 0.128 1996 0.900 0.750 0.150 1997 0.818 0.765 0.053 1998 0.683 0.806 -0.123 1999 0.718 0.775 -0.057 2000 0.571 0.725 -0.154 2001 0.805 0.838 -0.033 2002 0.787 0.721 0.065

75 From 1989 to 1997, the depth of annual freezing of clay soils generally exceeded the depth of annual thawing leading to a positive thermal offset value (Table 18). This favoured permafrost conditions to freezing, interannual accumulation, by a mean of 0.160 metres (STD = 0.063) over the 9-year span (Table 18).

After 1998, the depth of annual thawing exceeded the depth of annual freezing for clay soils leading to a maximum negative thermal offset value, permafrost unfavorable condition, of 0.154 metres of thawing in 2000 (Table 18).

For clayey soils and given the degree-day conditions from Figure 12 from 2004 to

2007, the thermal offset results showed depth of annual freezing of clay soils generally exceeded the depth of annual thawing leading to a positive thermal offset value (Table

19).

Table 19 – Results: Stefan Depths for Clay Soil Compositions (2004-2007) Stefan Depth - Permafrost Table (2004 - 2007) Clay λ(F) = 0.755x1.5, λ(U) = 0.755 Thermal Offset Year Df (m) Du (m) Df - Du (m) 2004 0.786 0.633 0.153 2005 0.918 0.827 0.091 2006 0.651 0.819 -0.169 2007 0.849 0.805 0.044

This favoured permafrost condition to freezing by a mean of 0.030 metres (STD = 0.140) since 2004 (Table 19).

In 2006, the depth of annual thawing for Arctic soils dominated by clay soils exceeded the depth of annual freezing, leading to a negative thermal offset value, loss of permafrost, of 0.169 meters of thawing (Table 19).

76 4.5.4 Peat and Organic Materials (1989 to 2007)

In Arctic soils dominated by peat with other organic matter and given the degree- day conditions from Figure 11 from 1989 to 2002, the thermal offset results were calculated using Equations 4, 5, 6 and 7 (Figure 17; Table 20).

Thermal Offset in Peat 1989 - 2007

0.250

0.200

0.150 0.100

0.050

0.000

-0.0501988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Thermal Offset Df - Du (m) -0.100

-0.150 Year

Thermal Offset Df - Du (m)

Figure 17 – Thermal Offset for Peat Compositions 1989-2007

From 1989 to 1997, the depth of annual freezing of peat generally exceeded the depth of annual thawing leading to a positive thermal offset value (Table 20). This favoured permafrost conditions to freezing, interannual accumulation, by a mean of 0.109 metres (STD = 0.043) over the 9-year span (Table 20).

77 Table 20 – Results: Stefan Depths for Peat Compositions (1989-2002) Stefan Depth - Permafrost Table (1989 - 2002) Peat λ(F) = 0.352x1.5, λ(U) = 0.352 Thermal Offset Year Df (m) Du (m) Df - Du (m) 1989 0.664 0.487 0.177 1990 0.652 0.498 0.155 1991 0.625 0.518 0.107 1992 0.605 0.459 0.146 1993 0.597 0.504 0.093 1994 0.603 0.521 0.082 1995 0.570 0.482 0.087 1996 0.614 0.512 0.103 1997 0.558 0.523 0.036 1998 0.466 0.551 -0.084 1999 0.491 0.529 -0.039 2000 0.390 0.495 -0.105 2001 0.549 0.572 -0.023 2002 0.537 0.493 0.045

After 1998, the depth of annual thawing exceeded the depth of annual freezing for

Arctic soils dominated by peat leading to a maximum negative thermal offset value, permafrost unfavorable condition of 0.105 metres of thawing in 2000 (Table 20). In

Figure 12 from 2004 to 2007, the thermal offset results were calculated using Equations

4, 5, 6 and 7 (Table 21).

Table 21 – Results: Stefan Depths for Peat Compositions (2004-2007) Stefan Depth - Permafrost Table (2004 - 2007) Peat λ(F) = 0.352x1.5, λ(U) = 0.352 Thermal Offset Year Df (m) Du (m) Df - Du (m) 2004 0.537 0.432 0.105 2005 0.627 0.565 0.062 2006 0.444 0.559 -0.115 2007 0.580 0.550 0.030

78 The depth of annual freezing of Arctic soils dominated by peat generally exceeded the depth of annual thawing leading to a positive thermal offset value by a mean of 0.021 metres (STD = 0.095) since 2004 (Table 21). In 2006, the depth of annual thawing for Arctic soils dominated by clay soils exceeded the depth of annual freezing leading to a negative thermal offset value, loss of permafrost, of 0.115 meters of thawing

(Table 21).

In palsa areas dominated in peat material with high soil moisture content and given the degree-day conditions from Figures 11 and 12 from 1989 to 2007, the thermal offset results were calculated using Equations 5, 6, 7 and 8 (Figure 18; Table 22).

Thermal Offset in Palsas (Dense Peat) 1989 - 2007

0.300

0.250

0.200

0.150

0.100

0.050

0.000

Thermal Offset Df - Du (m) 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 -0.050

-0.100 Year

Thermal Offset Df - Du (m)

Figure 18 – Thermal Offset for Palsa (Dense peat) Compositions 1989-2007

Table 22 – Results: Stefan Depths for a Palsa Formation (1989 – 2007) Stefan Depth - Permafrost Table (1989 - 2007) Peat λ(F) = 0.352x1.75, λ(U) = 0.352 Thermal Offset Year Df (m) Du (m) Df - Du (m) 1989 0.717 0.487 0.230 1990 0.705 0.498 0.207 1991 0.675 0.518 0.157 1992 0.653 0.459 0.194 1993 0.644 0.504 0.141 1994 0.651 0.521 0.130 1995 0.615 0.482 0.133 1996 0.664 0.512 0.152 1997 0.603 0.523 0.081 1998 0.504 0.551 -0.047 1999 0.530 0.529 0.001 2000 0.421 0.495 -0.074 2001 0.593 0.572 0.021 2002 0.580 0.493 0.088 2004 0.580 0.432 0.148 2005 0.677 0.565 0.112 2006 0.480 0.559 -0.080 2007 0.626 0.550 0.077

From 1989 to 2002, the depth of annual freezing of peat generally exceeded the depth of annual thawing leading to a positive thermal offset value (Table 22). This favoured permafrost conditions to freezing by a mean of 0.101 metres (STD = 0.094) over the 14-year span (Table 22). In 1998 and 2000, the depth of annual thawing exceeded the depth of annual freezing for Arctic soils dominated by peat leading to a negative thermal offset value, permafrost loss of 0.047 and 0.074 metres, respectively, from thawing (Table 22).

80 4.6 Soil Moisture Content Loss Test (2008)

The results from a soil moisture control loss test using nine (9) control soil containment samples were accomplished to simulate the loss of soil moisture over a five

(5) week period was conducted for the 2008 sampling campaign from March to April

2009.

The results showed an mean loss of 4.4 millilitres of moisture from samples in double and triple containment (Table 23). All samples showed decreasing results in water volume, the least being from T5 with a loss of -2.8 millilitres and the most with T6 at -6.9 millilitres over 5 weeks (Table 23).

Table 23 – Results: Soil Moisture Content Loss Test (2008) After-5 Initial Water Weeks Change in Water Volume Control Mass Mbw Water mass Water Density at Loss ID (Total) (g) M5wks (g) Mass (g) 23C (g/mL) (mL) T1 54.2 50.9 -3.3 0.9976 -3.3 T2 54.2 50.8 -3.4 0.9976 -3.4 T3 54.0 48.5 -5.5 0.9976 -5.5 T4 54.1 50.4 -3.7 0.9976 -3.7 T5 63.8 61.0 -2.8 0.9976 -2.8 T6 53.5 46.6 -6.9 0.9976 -6.9 T7 54.1 48.0 -6.1 0.9976 -6.1 T8 53.9 49.9 -4.0 0.9976 -4.0 T9 63.8 60.0 -3.8 0.9976 -3.8 MEAN 56.2 51.8 -4.4 --- -4.4 STD 4.3 5.1 1.4 --- 1.4

81 CHAPTER 5: Discussion

5.1 Soil Characterization

The soil samples retrieved from the study sites were visually analyzed and described based on visible characteristics of the soil, the composition, presence of soil organic matter, and with analyses on acidity and the gravimetric soil moisture content.

Acidity and soil moisture content (SMC) measurements from 2007 and 2008 have revealed acidic to neutral conditions (pH ~ 4 to 7) and variation in soil moisture content

(SMC ranged between 20 to 60%). Characterization of the accompanying soil sampling sites revealed the presence of soil organic matter, living and decomposing plant residues, and various moss and lichen compositions. Inland samples had low acidic pH values, the presence of soil organic matter, and the soil was dominantly clayey. Soil samples near the shores of Hudson Bay contained sandy soil and were slightly basic having a higher pH value.

The majority of the analyzed samples collected from the inland sampling sites in

Northern Ontario from 2007 and 2008 contained high contents of organic matter (Tables

4 and 5). Sphagnum and partially decomposed plant material was the major composition of the samples. Plant materials discovered included decomposing stems, roots, and leaves. Inorganic materials found in the samples were rocks and mineral sediments

(Tables 4 and 5). Samples found with high organic matter content, based on the site descriptions, had a lower pH value (pH of 4.41 from the 2007 campaign and pH of 6.17 from the 2008 campaign); suggesting acidic conditions (Tables 6, 7 and 8). Decomposing organic materials can release organic acids in moist conditions (Zoltai & Witt, 1995).

Gravimetric soil moisture content was higher for samples and sites with abundant organic

82 material located in clayey and silty soils. High gravimetric soil moisture content

(SMC~60%) conformed to high moisture conditions observed in the wet Hudson Bay lowland area, as there were abundant vegetation and organic material that can lead to a greater affinity for water in soils (Tables 6 and 8). The presence of peat formations,

Sphagnum, grasses and ideal soil compositions provide favourable conditions for the inland soils to retain soil moisture content. A relatively high soil moisture conditions for an inland site was observed at B5 with a gravimetric soil moisture content of 94% and pH~6 being ~50 km inland from the nearest Hudson Bay shore (Tables 5 and 7). Site B5 was highly organic which can withhold water molecules in the soil pore space (Seppälä,

2003). Based on the field notes provided from Gough, most of the samples with acidic conditions were extracted from sites situated in fens and bogs (Tables 4 and 5). Zoltai &

Witt (1995) suggested that fens and bogs have relatively low pH due to high degradation rates of organic matter contents in which supports the findings of the site soil characterizations.

The majority of the analyzed soil samples collected along the Hudson Bay coastal sites in Northern Ontario were dominated by sandy and gravelly soils (Tables 4 and 5).

There were little traces of soil organic matter. The observed organic material was observed from samples retrieved near the soil surface composed of primarily partially decomposed plant matter. The plant materials discovered included decomposing stems, roots, and peat. The dominant inorganic materials found in the samples were rocks and sediments ranging from sizes of pebbles (~ 10 mm in diameters) to gravel (~30 mm). The observed rocks were rounded and smoothed due to the processes of weathering and erosion from the shore and atmospheric actions. This area also experiences seasonal

83 freezing and thawing cycles. The sediments were unsorted resulting in conglomerate of different sizes, shapes and colours. The low gravimetric soil moisture content (~20%) for the coastal samples, in comparison to the inland gravimetric soil moisture content, can be attributed to the poor water retaining ability of sand and gravel with the lack of abundant organic material and clay minerals (Eyles & Miall, 2007; Tables 6 and 7). Without decomposing soil organic matter to produce humic acids, the coastal samples resulted in a higher mean pH value of 7.14 then compared to the inland pH of 6.17; basic conditions

(Tables 6 and 8). Weathering and chemical erosion of rocks, parent material and glacial sediments can produce a moderate base (Eyles & Miall, 2007).

Highly organic soils with high soil moisture contents can undergo considerable frost heaving by the formation of ice lenses that expand the soil volume (Guglielmin et al., 2008; Kuhry, 2008). The observation of palsas in the Hudson Bay Lowlands provides direct evidence to support frost heaving and the formation of ice lenses. However the presence of excess soil moisture content for palsa development suggests warmer conditions in the area followed by sufficient seasonal cooling to provide freezing, this imply significant changes per season in the thickness of soils due to heaving and melting that can modify the topography (Thie, 1974; Gross et al., 1990; French, 1999; Henry,

2000; Spielvogel et al., 2004; Kim et al., 2008; Larsen et al., 2008; Wang et al., 2009).

84 5.2 Freezing and Thawing Degree-Days

The freezing and thawing degree-days were determined using actual weather data from Peawanuck weather station in Northern Ontario. The threshold in determining freezing and thawing was set at 0ºC. As shown in Figure 11, in the span of 14 years from

1989 to 2002 the number of freezing degree-days had decreased with statistical significance (r = -0.812, R2 = 0.660; p-value = 0.000; Table 12). The lowest number of freezing degree-days was calculated at 557 for the year of 2000 (Figure 11). For the thawing degree-days with minor variation was observed over the 14-year span (p-value =

0.106; STD = 163.93; Table 12). The thawing degree-days increased to a peak number of days of 1,798 calculated for the year of 2001 before decreasing near the mean thawing degree-days for 2002 (Figure 11 & Table 12).

The freezing and thawing degree-days was calculated for a second interval of 4 years from 2004 to 2007, this was due to the incomplete temperature data provided by the

Peawanuck weather station during 2003 (Figure 12); this is further discussed in Section

5.8 Sources of Error & Uncertainties. As shown in Figure 12, in the span of 4 years from

2004 to 2007 the number of freezing degree-days had slightly increased, however this was not statistically significant (r = 0.077, R2 = 0.006; p-value = 0.920; Table 13). The lowest number of freezing degree-days was calculated at 722 for the year of 2006 (Figure

12). A sharp increasing trend was observed for the thawing degree-days from the years

2004 to 2005 with minor variation afterwards, however this was not statistically significant (p-value = 0.105; Figure 12). The thawing degree-days had increased to a peak number of days of 1,751 calculated for the year of 2005 before slightly decreasing to 1,659 thawing degrees days for year of 2002 (Figure 12 & Table 12).

85 An analysis of the degree-day trends for Peawanuck, Northern Ontario has shown that since 1993, the numbers of thawing degree-days have exceeded the numbers of freezing degree-days, suggesting a warming trend in the region (Figure 11). With increased number of thawing degree-days and decreased number of freezing degree-days

(T-test two-tailed p-value = 0.002; Figures 11 and 12), climatic and environmental conditions have become unfavourable for permafrost presence. As this region is located in the southern portion of the Arctic and parts in the Subarctic, the permafrost state in the region is likely and most susceptible to be in decline. This degradation of permafrost would be amplified in surface areas without vegetation and organic layers that could provide insulation against thawing energies.

5.3 Stefan Depth and Permafrost Table

The Stefan depth of freezing (Df) and thawing (Du) were used to calculate the thermal offset (Df - Du) to provide an estimate of the thickness of the active layer and permafrost with projections of the permafrost table (Tables 14 to 21). In the winter season, dominated by negative ground heat flux, the freezing energies can penetrate down the soil column represented by the Stefan depth of freezing derived from freezing degree- day with temperatures less than 0°C. This provided a seasonal estimate of the depth of soil susceptible to freezing. In the spring-summer seasons, thawing of the active layer begins when sufficient incoming solar radiation and geothermal heats allows for a positive ground heat flux state (Ling & Zhang, 2004; Carey et al., 2007; Hayashi et al.,

2007). The geothermal heating at the permafrost base is not discussed in this thesis.

Heating from the atmosphere will first remove the insulating snow cover from the surface

86 before thawing the active layer (Muller, 2008; Zhang et al., 2008b). The depth of thawing is determined with the Stefan depth of thawing calculation.

In areas south of the subarctic, it is typical to have a negative thermal offset (Du >

Df) condition (Burns & Smith, 1987; Duan & Naterer, 2009). This represents seasonal freezing during the winter season followed by a complete thawing of the soils in the summer season. When the seasonal Stefan depth of thawing does not exceed the seasonal

Stefan depth of freezing (Du < Df), the resulting positive thermal offset represents the theoretical thickness of a frozen layer of soil that has persisted over the summer thawing season, and has survived into the next freezing cycle (Burns & Smith, 1987; Duan &

Naterer, 2009). Since permafrost is defined as permanently frozen soils that remain frozen for at least two consecutive years, this layer of frozen soil must persist through a second summer-thawing cycle (Gough & Leung, 2002; Shur & Jorgenson, 2007; Muller,

2008). If the positive thermal offset (Du < Df) condition persists over two warming seasons, the soil state would be classified as the development of permafrost or permafrost present (Burns & Smith, 1987; Duan & Naterer, 2009). In regions with continuous permafrost zones, such as in the Arctic, positive thermal offset conditions will lead to the thickening of the permafrost layer (Burns & Smith, 1987; Duan & Naterer, 2009).

Negative thermal offset conditions in the Arctic will lead thinning of the permafrost layer and the development of thicker summer active layers; the permafrost table represents the interface at which the extent of the depth of thawing ends and meets the permafrost layer

(Burns & Smith, 1987; Muller, 2008; Duan & Naterer, 2009). In discontinuous permafrost zones such as in the Subarctic, negative thermal offset conditions can result in the disappearance of permafrost.

87 The Stefan depths calculation, using Equation 4 required the soil thermal conductivity (λ). Soil thermal conductivity is strongly influenced by the soil moisture content and the type of soils. Calculations of Stefan depths were categorized based on the typical composition of Cryosols that dominated by sand (porous and non porous), clay, and an organic top layer, peat. Theoretical dry soil conductivities (0% soil moisture content) were assigned to the four categories as follows: porous sand (λ = 1.99), non- porous sand (λ = 0.787), clay (λ = 0.755) and peat (λ = 0.352). The thermal conductivities for moist (20% soil moisture content) and frozen soils were increased by a factor of 1.5 to the dry soil conductivities (Nixon & McRoberts, 1973; Kujala et al., 2007). The dry soil thermal conductivities, representing warm summer soil conditions, were applied in the

Stefan Equation to calculate depth of thawing (Du) (Equation 5). The enhanced thermal conductivities for moist and frozen soils represented the winter conditions in calculating the Stefan depth of freezing (Df) equation (Equation 6). The generalized soil conductivities were applied, as there were no accessible previous soil investigations conducted in study area. Peat was identified as a thermal insulator resulting as having the least conductivity. The greatest conductivity was assigned to porous sand due to the large porosity (typically 33%) and high soil water capacity (Dunne & Leopold, 1978; Price &

Waddington, 2000).

The study area is located in the continuous permafrost zone (along the shores of

Hudson Bay) and in the region of discontinuous permafrost (further inland in Northern

Ontario). The thermal offset values can be applied as an annual change to permafrost thickness (Burns & Smith, 1987; Natural Resources Canada, 2006). In general, the results of the thermal offsets showed positive thermal offset conditions favourable to

88 permafrost in the years from 1989 to 1997, 2002 to 2005 and 2007; the remaining years

(excluding 2003) showed negative thermal offset values (Tables 14 to 22). The greatest thermal offset was experienced in the porous sandy soils due to the high soil conductivity value (Tables 14 and 15). The least thermal offset was experienced by organic peat layer due to the low soil conductivity value and thermal insulating properties (Tables 20 and

21).

5.4 Permafrost Presence

Using the Stefan depth calculations for permafrost (Equation 4) and the degree- days, extracted from weather station data, from 1989 to 2007 (Figures 11 and 12), the thermal offset was calculated to determine the change in permafrost thickness. Actual depths to permafrost were measured during the 2007 and 2008 field sampling campaigns

(Figure 5). Mechanically in 2007 field campaign, permafrost was deemed present when a graded metal rod could no longer be drilled into the subsurface (Figure 6). Difficulties can arise in differentiating the impact of the rod on the permafrost table or with a buried obstruction, such as a rock or an ice lens (Mühll et al., 2002). The presence of permafrost in 2008 was determined using thermistor probes that were lowered into an augured borehole (Figure 7). The thermistor measured ground soil temperature and recorded the temperature range on a data logger. When the soil temperature was reported near or at

0°C, the sample site was deemed to be permafrost present (Smith & Burgess, 2002;

Nicolsky et al., 2009).

Annual depth to permafrost measurements provides monitoring information of the active layer thickness and the state of the permafrost at the study sites (Nicolsky et al.,

89 2009). Using this information, trends can be used to assessment the future state of permafrost for the region such as estimating the mean reduction of permafrost and the extension of the active layer (Anisimov & Nelson, 1996; Nicolsky et al., 2009; Pang et al., 2009). Averaged depths to permafrost were calculated from the measured sampling points located in each of the three quadrants in Table 11 to represent the western, central and eastern portion of Northern Ontario and the shores of Hudson Bay (Tables 10-12). A significant annual variation between the mean depth to permafrost of August 2007 and

2008 was observed (Figure 5; Table 11). In 2007, the depth to permafrost ranged between

40 to 50 centimetres while in 2008 the depth to permafrost ranged between 110 to 140 centimetres from the surface (Table 11; Figures 11 and 12). The results of 2008 were roughly three times greater than the depths measured in 2007 which could be explained due to different sampling strategies as there was a focus in the coastal regions for 2008 and inland for 2007; the coastal sites were dominated by sandy soils and the inland sites contained greater organic material content. As observed in the 2008 results of the three quadrants in Table 11 and Figure 7, there was a decrease in the depths to permafrost from west to east, Quadrants 1 to 3, suggesting asymmetrical thawing of the active layer and permafrost. The depth to permafrost measurements suggests thicker active layer developments were experienced in Quadrant 1, an enhanced thawing event. In Quadrant

3, the influence of the peat and organic material may have insulated and reduced the thawing energies on the active layer and permafrost. In comparison to the 2007 mean depth to permafrost results in Table 11, Quadrant 3 experienced less thawing than compared to Quadrant 2. A direct explanation of these trends for Quadrant 3 was not investigated for this thesis and further research in area should be conducted.

90 Based on the descriptions listed in Table 4 and 5, highly vegetated areas and high organic matter in the soil composition was documented as distance progressed inland with the sample sites. The highly organic layer of peat and vegetation above the active layer could provide thermal insulating benefits (Thie, 1974; Hinkel et al., 2001; Cheng et al., 2004; Spielvogel et al., 2004; Martini, 2006; Zhang et al., 2008b; Pang et al., 2009).

Based on the results in Table 8, the high organic composition observed at the sample sites could provide thermal insulation for permafrost against heat energy penetrations through the active layer and reduced the severity of thawing in the summer. In the winter, an upper snow layer above the soil provides an additional thermal insulation that can prevent freezing energies, increase thermal resistance, from entering the soil column to enhance the permafrost (Cline, 1997; Cheng et al., 2004; Osterkamp, 2005; Zhang et al., 2008b).

Lowland areas in bogs and fens have significant organic matter and soil moisture that allowed well-aggregated conditions to further retention of soil water in the soil pores

(Juma, 2006; Carey et al., 2007; Kim et al., 2008; Kuhry, 2008). However, as established with Shur & Jorgenson (2007), an increase in soil moisture content could result in an increase in thermal conductance of energy with respect to different soil compositions.

Near the shores of Hudson Bay, active layer thawing depth were seen to be higher than inland, this can be attributed to the low organic matter content, sandy soil composition with moderate moisture conditions near the body of water (Table 7 and

Figure 5). Without the high organic matter composition, a thermal insulating layer cannot be effectively established over the active layer. Sandy and moist soils enhance the soil

91 conductivity and allow further penetration of heat energy into the soil column resulting in a greater Stefan depth of thawing (Tables 14 to 17).

Acidity in the inland soils ranges from pH of 5 to 7 and remains acidic conditions of the soil samples in Tables 6 & 8 could be attributed to the organic matter content in

Tables 4 & 5 possibly due to the production of organic and humic acids. Since the study area is located on the Canadian Shield as the parent bedrock material, there is little capacity for chemical dissolution to provide buffer conditions for the soils (Eyles &

Miall, 2007).

Thermal offset calculations from the degree-days observed at Peawanuck revealed permafrost to be in a fluctuating state of freezing and degradation with high degradation rates to have occurred from 1998 to 2001 before recovering to a positive thermal offset.

In the summer months, permafrost unfavourable conditions exist as air temperatures are above freezing allowing the growth of the active layer (Shur & Jorgenson, 2007). Over winter, permafrost growth by incorporation of the active layer base can occur when conditions favour permafrost development (Shur & Jorgenson, 2007). Overall, there was a negative thermal offset in 2006, resulting in a reduction of permafrost thickness by a minimum of 0.115 metres in peaty soil and a maximum of 0.274 metres in sandy soils

(Tables 16 and 21). With further studies on thermal offset in this region, prediction of the permafrost fate along the shores of Hudson Bay and in the Northern Ontario region can be projected.

92 5.5 Palsa Presence

Shallow active layers above the permafrost were observed in palsas with highly acidic and moist characteristics due to the organic matter content (Figure 19). In moist conditions, thermal conductance can be enhanced for heat transfers to the soil column.

For the palsas observed in July and August of 2007 and 2008, the organic top layer of

Sphagnum species and peat formations served as an insulating layer that prevented further energy penetration from the atmosphere to the soil. Based on the field notes, palsas were situated in fens, bogs and peat lands that are high in moisture and organic matter (Tables 4 and 5). Soil samples collected from palsas contained higher soil moisture contents. The thick organic layers did protect against permafrost degradation by reducing the severity of heat energy penetration (Figure 19; Tables 6 & 21). The layer of organic material can enhance freezing of soil moisture in the winter causing the expansion and raised soil column to form the circular mounds (Kujala et al., 2007;

Kuhry, 2008). Palsa acidity ranges more broadly from a pH of near 3 to a pH of 7 (Tables

4 and 6). The analysis of the freezing and thawing degree-days showed a change in the

1990s where the number of thawing degree-days has exceeded the freezing degree-days suggesting unfavourable climatic conditions for permafrost and palsas. However, even in the summer, palsas are able to remain intact and present in the landscape possibly due to the enhanced organic peat layer protection.

Due to limitation on literature surrounding the interactions of palsas in nature, the exact purposes of these features remain understudied and not well understood. Palsas may have an ecological role in the habitat of Polar bears. Field notes from both 2007 and

2008 have reported disturbed palsa, possibly due to polar bear activity in the region in

93 search of den locations or for cooling purposes near the permafrost (Figures 19 & 21).

Female polar bears are known to exhibit site-fidelity behaviour for dens in Northern

Ontario (Crompton et al., 2008). With climate change and shifts in the terrain with melting permafrost, the impact on inland polar bear food sources may lead to changes in feed behaviour (Dyck et al., 2007; Callaghan, 2008). Dyck et al (2007) cautions that impacts on polar bears from climate change is still not well understood as there are many interconnected factors that can affect distribution, feeding behaviour, body mass and survival; however, it should be noted that early breakup of sea ice experienced in Hudson

Bay may be a major factor in polar bear survival (Gagnon & Gough, 2005; Stirling et al.,

2008).

5.6 Addressing Research Question 1

• 1. Can the distribution of permafrost in Northern Ontario be rationalized using the

relationship between soil moisture content and the frozen and unfrozen soil

thermal conductivities, “the thermal offset” as hypothesized by Gough and Leung

(2002)?

By establishing relationships of soil thermal conductivity with soil moisture content and thermal offset trends over time, using the Equation 7 from Burns & Smith

(1987), the presence of permafrost can be predicted. The presence of permafrost will ultimately depend on the climate conditions that are favourable for permafrost formation

(Shur & Jorgenson, 2007). Continuous and discontinuous permafrost zonation can be determined using the Frost number calculation from Equation 1 as suggested by Nelson

& Outcalt (1987); however, as shown in Gough & Leung (2002), there were

94 discrepancies between calculated Frost Numbers with field observations in the Hudson

Bay Lowlands. The application of the thermal offset approach includes the soil moisture effect that has shown support to the field observations (Tables 14 to 21; Gough & Leung,

2002). This research furthers the understanding of the presence of continuous permafrost in Canada‟s subarctic region of Northern Ontario due to the thermal offset phenomenon while calculations of Frost numbers and observations in southeastern Hudson Bay show discontinuous permafrost. By using degree-days in this research in establishing the Stefan depths of thawing and freezing, this allows the thermal offset to be calculated. Unlike the

Frost number, which aids in permafrost zone classification, the thermal offset allows estimations on the direct changes to permafrost thickness. With available permafrost thickness measurements and the thermal offset, a timeframe could be estimated using projected climate scenarios to predict the fate of permafrost for a region. Since freeze- thaw degree-days requires temperature data collected at weather stations, issues pertaining to data quality arise from the use of transposed data from neighboring locations to remote sites that lack a permanent weather station. This remains an academic issue, as these temporal and spatial variations in temperature can lead to misrepresentations in theoretical calculations that may not be represented with real world observations, as seen in the application of the Frost number by Gough & Leung (2002).

Based on this research and the data provided, the thermal offset was calculated for the Peawanuck region using various values of soil thermal conductivities based on dominant arctic soil compositions. Temperature data was provided from a pre-existing weather station at Peawanuck, Ontario, for this undertaking. Temperature data allowed the calculations of the degree-days required for the Stefan depths equation that ultimately

95 allows for assessing the presence of permafrost through the thermal offset approach. To determine the fate of permafrost and its future presence in this subarctic region both climatological and environmental factors must be considered in order to represent the complexities of natural system. Long-term monitoring of permafrost is necessary since the behaviour of permafrost is seasonally and temporally dynamic, permafrost can thicken over one winter, so that variation can lead to new depths to permafrost in the following summer or completely melt. Important environmental factors that should be considered are thermal insulation by organic matter and vegetation that can enhance and protect permafrost thickness, prolonging permafrost presence. Biological activity is an important factor that is difficult to assess, such as polar bears disturbances of the upper and active layers that can have impacts on permafrost insulation (Figure 19). Inorganic factors will have strong influences on the energy conductance of the soils above the permafrost, such as soil composition, moisture content, and acidity. The resulting complexity of the question proposed for this research has shown that with simplification of nature, estimations and trends of permafrost presence and extent can be determined for a region. The trend of the calculated thermal offset for Peawanuck, Ontario, suggested a weak negative trend from the shores of Hudson Bay and inland into Northern Ontario; this suggests greater permafrost shifts are likely to occur near the shores of Hudson Bay where soils are dominant porous with sands and gravel, and where vegetation and organic insulation and protection is weaker; less soil moisture also weakens the thermal offset effect. Further inland in peaty and clayey soils, the thermal offset of permafrost showed a weak negative trend suggesting events favourable to thawing however, the severity is reduced due to the protective insulation layers of organic material and peat. For accurate

96 results, long-term monitoring, installation of weather stations in remote areas, and geophysical methods in surveying permafrost should be adapted to provide better resolution and include variables from all the physical factors influencing the permafrost.

5.7 Addressing Research Question 2

• Does the presence of palsas affect the thermal conductivity of soil from the

surface cover down to the permafrost?

The presence of palsas can affect the thermal conductivity of soil, from the surface cover down to the permafrost, due to the high organic matter presence that has affinity for soil moisture and provides a thermal insulation effect. The formation of palsas resulted from the enhancement of the permafrost core from favourable conditions, such as the insulating properties of vegetation and organic matter layers. Peat and mosses prevent thermal conductance of heat energy in the summer air to the permafrost and prevents permafrost degradation. The same process can enhance the cold penetration into the palsa, via thermal offset, in the fall and winter seasons. If there is no insulating snow cover, the enhanced cold penetration can freeze additional soil moisture and strengthen the palsa formation. Based on the reviewed studies and the site characteristics conducted from soil samples of palsas, there is evidence that suggests that the characteristics of the thick organic layers above the active layer in a palsa does decrease thermal conductivity of heat energy from the surface to the permafrost. In comparison of thermal offset results for 2006 in Table 20, peat soil (-0.115 m), and Table 22, palsa formation (-0.080 m), the additional organic material and soil moisture enhances the soil thermal conductivity by a factor 1.75 (thermal offset effect) for the Stefan freezing depth allowing for a greater cold

97 penetration (0.480 m for palsa in comparison to 0.444 for peat soils) that reduces the impact of the summer thawing penetration. Since only a few authors dominate the scientific literature on palsas in general, further studies are crucial and necessary to determine the role and thermal dynamics of palsas in the arctic. It should be noted that from the field study, palsas may have a significant ecological role for polar bears as evidence have suggested that polar bears have be attempting to construct habitats and dens near and on palsas (Figure 19).

5.8 Sources of Error and Uncertainties

Traditional permafrost delineation methods involved drilling boreholes. Since subsurface materials, such as the organic layer and unconsolidated sediment layers, are not homogenous in nature, it is difficult to auger boreholes in moist soil conditions as the integrity of the borehole walls may collapse. Utilizing an auger can generate heat in the borehole along the walls and this may thermally contaminate the thermistor readings leading to inaccurate soil temperature results. With this important error, soil temperatures close 0ºC, up to 4ºC, were accepted as permafrost present.

The data collected from boreholes in the study area provided point-scale resolution specific to the sampling site. The combination of multi-borehole data in this analysis for the quadrants extrapolated the results between boreholes to produce data on a regional scale. Since permafrost presence is site specific, up scaling to a larger scale reduces the resolution of site-specific characteristics, and this up scaling technique assumes a homogenous subsurface approach.

98 Sources of error for laboratory analytical methodology could be due to a time difference between soil collection and laboratory analysis work in which there was a month disjunction from August to October. A soil moisture control loss test of 9 control samples was accomplished to simulate the loss of soil moisture through the sampling containments over a one month period was conducted for the 2008 sampling campaign.

The results showed a mean loss of 4 millilitres of moisture from samples in single, double and triple containment (Table 23). To rectify this error, an addition of a correction factor of 7% was added to the measured gravimetric soil moisture values, also in millilitres, and then converted to gravimetric soil moisture content in unit percentage.

Observation of the soil characteristics was extremely difficult to visually identify as soil or peat due to partial decomposition; vegetation and fungus species proved difficult to identify due to partial fragments and decomposition.

The gravimetric soil moisture content was conducted since this accepted method allows for simple and direct measurements without bulk density information. Few soil sample containments did leak and this may have altered the gravimetric soil moisture content. Since the soil samples were not filled to the volume of the sample containers and with the time difference, the bulk density of the soil could not be determined to convert gravimetric soil moisture content to the volumetric soil moisture content.

In calculating the degree-days of freezing and thawing, temperature data from

1986 to 2007 was acquired from weather stations in the study area (Figure 2). Incomplete yearly temperature data sets were examined and years with extreme gaps in data, greater than 30 missing days, were omitted from the calculation. Temperature data sets from

1986 to mid-1988 and 2003 were incomplete and omitted (Figures 11 and 12). To ensure

99 full data sets, missing days up to five consecutive days were corrected using linear regression from the beginning and the end of the month. Individual missing days were corrected using an arithmetic mean value of the temperature on the day before and after.

While determining the Stefan depths and thermal offset, the quality of degree-day data was limited to the quality of the extracted temperature data. Uncertainty in the temperature data could influence the final results of the thermal offset calculations. The thermal offset calculation required values for soil conductivity, which could not be determined at the time of soil sampling. Generalized soil thermal conductivities were applied based on the literature review for Arctic soils and peat. With additional field data on the soil composition and site characteristics, an accurate soil thermal conductivity could be achieved by applying the de Vries Equation (Equation 2) that could be utilized in the thermal offset estimations.

Using Geographical Information Systems (GIS), errors of significant digits may have led to some inaccuracies in determining distances between the sample sites and the

Hudson Bay shore based on the map produced (Figures 5, 6 and 7). Electronic maps of the Northern Ontario region used for this study were was geo-referenced from 1984 and compiled in 1992. The study area and sampling region spanned over two Universal

Transverse Mercator coordinate systems, the UTM 16 and 17. UTM 16 was selected as the projection in generating the map figures. Slight geographical shifts to the actual sampling locations may have occurred with this selected projection.

100 5.9 Potential Research Impacts on Society

The results from this undertaking established data for permafrost presence to be estimate based on soil moisture content, temperature data and soil thermal conductivity properties. Incorporating the results of this research in establishing physical relationships of soil thermal conductivity in the development and degradation of permafrost can allow models and predictions in the fate of permafrost. The region of Northern Ontario along

Hudson Bay is situated at the southern edge of the sub-Arctic zone. With climate warming, this region is at the frontline of environmental change as shift in physical properties of the permafrost can result in destabilizing structures erected on the permafrost and palsa formation and degradation which is a significant safety risk for northern communities of Canada (Vyalov et al., 1993; Sorochan & Tolmachev, 2006).

An ongoing concern in Arctic regions and northern communities pertains to delineating and predicting the movement of contaminants in contaminated sites located in continuous and discontinuous permafrost states (Delaney et al., 2001; Tsuji et al., 2001;

Kalinovich et al., 2008). With changes to the underlying permafrost, sites such as the relic radar station at Winisk still possess potential subsurface contamination concerns

(Tsuji et al., 2001). The transitional layers between the active layer and permafrost table forms finger-like grooves and channels (Eyles & Miall, 2007; Kalinovich et al., 2008).

With thawing of the active layer, the permafrost table becomes asymmetric (Delaney et al., 2001; Kalinovich et al., 2008). Since permafrost is considered impermeable, these finger-like grooves and asymmetric topography will influence the flow paths for contaminants resulting in difficulties in delineating contaminated sites, especially, since the permafrost table can have considerable temporal and spatial variability within one

101 freezing and thawing cycle of a year (Delaney et al., 2001; Tsuji et al., 2001; Eyles &

Miall, 2007; Kalinovich et al., 2008).

As Canada continues to develop northwards with the sub-Arctic being the forefront of climate change, permafrost research can provide predictions and assessments in determining the impacts of shifting ground. The processes of frost heaving and the degradation of permafrost are continuing concerns to existing and future building foundations and transportation infrastructures, which can be destabilized and cause risks to human health and safety (Sorochan & Tolmachev, 2006; Eyles & Miall, 2007; Pang et al., 2009). In the physical process of freezing soil water into ice, volumetric expansion occurs in the soil with an increase in mechanical strength that can be compromised by melting, and further exacerbated by resulting melt water (Eyles, 2006; Duan & Kim et al., 2008; Duan & Naterer, 2009; Pang et al., 2009). Impacts can lead to ground subsidence, settlement and infrastructure foundation failures that can cost significant amount of damages and expenses for constructions, repairs, renovations and planning

(Ling & Zhang, 2004; Eyles, 2006; Sorochan & Tolmachev, 2006; Duan & Kim et al.,

2008; Jin et al., 2008; Larsen et al., 2008; Naterer, 2009). Permafrost predictions and models have economical importance for civil construction and engineering of oil and gas pipelines, for military infrastructure developments in Canada‟s Arctic regions, and for transportation networks. Continuing permafrost research can further develop adaptation methods by planners and engineers to improve the quality of life, reduce risks, and improve safety for Canada‟s First Nation peoples and northern communities.

102 CHAPTER 6: Conclusion

6.1 Permafrost

The dominant physical processes governing permafrost presence were identified as: climate and environmental conditions, ground heat flux, and soil thermal conductivity properties (Nixon & McRoberts, 1973; Burns & Smith, 1987; Halliwell & Rouse, 1987;

Nelson & Outcalt, 1987; Hinkel et al., 2001; Gough & Leung, 2002; Mühll et al., 2002;

Smith & Burgess, 2002; Cheng et al., 2004; Yoshikawa et al., 2004; Overduin et al.,

2006; Carey et al., 2007; Hayashi et al., 2007; Shur & Jorgenson, 2007; Kujala et al.,

2007; Kneisel et al., 2008; Muller, 2008; Zhang et al., 2008a; Duan & Naterer, 2009;

Nicolsky et al., 2009; Wang et al., 2009). Changes in these processes can either favour permafrost formation, aggradation, or degradation. This supports the hypothesis presented by Gough & Leung (2002), the analyses of the soil samples provided and the literature reviewed suggest evidence that soil thermal conductivity has shown to play a substantial role in permafrost presence in the Hudson Bay region. Both evidence from the laboratory analyses and site descriptions in support of Shur & Jorgenson (2007) suggests that soil moisture content can influence and enhance the conduction of energy through the soil column. Since soil thermal conductivity is not a factor in the Frost number and the rate of permafrost thawing equations, the use of Stefan Equation in determining the thermal offset is appropriate for determining the state of permafrost (Burns & Smith,

1987). The Stefan depths utilize the number of freezing and thawing degree-days and include the soil thermal conductivity that can be influenced by soil moisture content and by soil compositions (Nixon & McRoberts, 1973; Nelson, 1986; Hayashi et al., 2007;

Hughes & Braithwaite, 2008). The complex interactions of soil organic matter enhances

103 soil moisture and acidic conditions, and that the layers of organic matter can provide unique insulating effects that can protect and favour permafrost presence (Zoltai & Witt,

1995; Yoshikawa et al., 2004; Carey et al., 2007). Since 1993, there has been a shift in

Northern Ontario favouring a decreasing trend in freezing degree-days (p-value = 0.000;

Table 12).

This research concludes that permafrost is present in the Northern Ontario areas dominated by organic materials such as peat with clayey soils. The organic material and clayey soils provides high soil moisture content that enhances the soil thermal conductivities during the winter to favour the freezing process while the organic layer in the summer provides insulation against the thawing energies. At the shoreline of Hudson

Bay, the thin layer of organic material with sandy soils provide an enhanced soil thermal conductivity that allows greater extents of thawing in the summer and freezing in the winter; however, since the shore areas are located further north and experiences a cooler climate than in the southern lands allowing for permafrost favourable conditions. Overall, permafrost in the Hudson Bay Lowlands and shores are expected to remain present. With continuing warming trends, it is not unreasonable to conclude the possibility that there may be a future shift at the southern extent of the subarctic in Northern Ontario to be reclassified from being a continuous permafrost zone to the discontinuous permafrost state, and a further shift of the current discontinuous permafrost zone in the south to the sporadic permafrost state. Future studies in the southern extent of the subarctic should monitor for indicators of permafrost degradation as referenced in French (1999) for: (1) increase in active layer thickness, (2) increases in permafrost degradation, and (3) evidence of slope and active layer failures.

104 6.2 Palsas

Based on observations in the field, this research has incorporated palsas into this research. Thermal offset results have shown that soils high in organic matter content can reduce the soil thermal conductivities to provide a layer of insulation for the permafrost below; this process has permitted the formation of palsa features on the arctic terrain

(Table 23; Seppälä, 2003; Kuhry, 2008). The exact role and characteristics of palsas have not been widely studied in Northern Ontario; however, observations of these unique formations have shown ecological and habitat significances for Polar Bears in the region

(Brown, 1973). The dominant physical processes governing the presence of palsas were identified as thermal conductivity of peat, snow cover and wind speed (Brown, 1973;

Seppälä, 1986; Seppälä, 2003; Kujala, et al., 2007; Vallée & Payette, 2007; Kuhry,

2008). The results from this research concluded that peat layers have the least soil thermal conductivity in comparison to sand and clay soil compositions allowing the peat layer to provide insulation against thawing energies in the summer. The presence of snow cover in the winter and winds proves detrimental to the presence of palsas as snow cover insulates against freezing energies in the winter from thickening the underlying permafrost (Seppälä, 1986). Wind actions deposits snow against the palsas and can provide additional erosion actions against the palsas reducing the structural stability favouring degradation (Brown, 1973; Seppälä, 1986; Kuhry, 2008; Zhang et al., 2008b).

Since Polar Bears tend to establish dens or utilize palsas for cooling purposes in the summer, it is possible for Polar Bears to assist in the degradation process by the removal of the insulating peat layer and by exposing the permafrost to the atmosphere. Changes in the permafrost can alter the landscape and drainage network affecting food sources for

105 biota and change population distributions (Dyck et al., 2007; Callaghan, 2008; Crompton et al., 2008). With continuing warming trends, it is not unreasonable to conclude that in discontinuous and sporadic permafrost zones, the most likely location to observe permafrost would be in areas dominated in organic material and sites beneath palsas

(Brown, 1973).

6.3 Recommendations for Further Research

Further research on the physical properties of permafrost in the Arctic region will allow accurate models to predict the presence and potential degradation of permafrost.

With the aforementioned statement, continuous research as part of a long term climate and permafrost monitoring program and network is recommended to establishing a continuous and accessible database of permafrost measurements for Northern Ontario.

Long term monitoring of the climate conditions can be accomplished by the deployment and installation of portable weather stations within the study area that are connected to data loggers to record continuous air and soil temperature measurements. A second recommendation for further research is the application of geophysical methods and tools to compliment field investigations and soil sampling campaigns to provide better resolution of the active layer thickness, depths to permafrost, soil moisture contents and actual permafrost thickness data. The use of geophysical methods and tools allow measuring physical properties on a broad spatial scale and the collected data can be applied to Geographical Information Systems (GIS) to produce maps, regional distributions and models of permafrost. This can provide a better understanding of the permafrost state for civil engineering projects in the northern First Nation communities.

106 Finally, a third recommendation for further research is to focus on the dynamic ecological and environmental importance of palsas in Northern Ontario and to map the distribution of palsa features with GIS. Since palsa-polar bear interactions have been observed at palsas, possibly in search of a den or for cooling purposes, detailed assessments and research should be conducted to provide better knowledge of the impacts of climate change on polar bears in this region (Figures 19 & 21). Further research in permafrost and palsas will not only benefit the academic community but also for those currently residing in Canada‟s Arctic and Subarctic regions where transportation, resources, and infrastructures depends on understanding the state of permafrost.

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114 APPENDIX – Additional Figures

Figure 19 – Excavated Palsa located in a vegetated region in Northern Ontario. Digital photo taken by William Gough, July-August, 2007. Note: Exposed internal core of the palsa, possibly due to Polar Bear activity in the region

Figure 20 – Soil Samples baking in the oven at 105˚C for gravimetric soil moisture content analysis: oven drying in the Science Wing Room 313 Laboratory. Picture was taken on 4 OCT 08 by A. Tam.

115

Figure 21 – Three male polar bears in Northern Ontario, August 2007. Digital photo was taken by William Gough.

116