Arctic Ecology

The Arctic is often portrayed as being isolated, but the reality is that the connectivity with the rest of the planet is huge, be it through weather patterns, global ocean circulation, and large-scale migration patterns to name but a few. There is a huge amount of public interest in the ?changing Arctic?, especially in terms of the rapid changes taking place in ecosystems and exploitation of resources. There can be no doubt that the Arctic is at the forefront of the international environmental science agenda, both from a scientific aspect, and also from a policy/environmental management perspective.

This book aims to stimulate a wide audience to think about the Arctic by highlighting the remarkable breadth of what it means to study its ecology. Arctic Ecology seeks to systematically introduce the diverse array of ecologies within the Arctic region. As the Arctic rapidly changes, understanding the fundamental ecology underpinning the Arctic is paramount to understanding the consequences of what such change will inevitably bring about.

Arctic Ecology is designed to provide graduate students of environmental science, ecology and climate change with a source where Arctic ecology is addressed specifically, with issues due to climate change clearly discussed. It will also be of use to policy-makers, researchers and international agencies who are focusing on ecological issues and effects of global climate change in the Arctic.

About the Editor

David N. Thomas is Professor of Arctic Ecosystem Research in the Faculty of Biological and Environmental Sciences, University of Helsinki. Previously he spent 24 years in the School of Ocean Sciences, Bangor University, Wales. He studies marine systems, with a particular emphasis on sea ice and land-coast interactions in the Arctic and Southern Oceans as well as the Baltic Sea. He also edited a related book: Sea Ice, 3^rd Edition (2017), which is also published by Wiley-Blackwell.

Preface xiii

List of Contributors xv

1 What Is the Arctic? 1
Kjell Danell

1.1 Setting the Scene 1

1.2 In Which Ways Is the Arctic Different? 2

1.3 How Was the Arctic Discovered? 3

1.4 How Large Is the Arctic? 4

1.5 What Is in the Arctic? 4

1.5.1 Arctic Haze and Ice Fog 4

1.5.2 Aurora Borealis 5

1.6 Climate and Weather 5

1.7 Ice and Snow 6

1.8 Permafrost, Polygons, Pingos, and Palsas 6

1.9 Animals, Plants, and Fungi 7

1.10 Arctic Ecosystems 9

1.10.1 Terrestrial Ecosystems 10

1.10.2 Freshwater Ecosystems 12

1.10.3 Marine Ecosystems 14

1.10.4 Humans 15

1.11 Which Natural Resources and Ecosystem Services does the Arctic Offer? 17

1.12 Biotic Changes in the Arctic 19

References 22

2 Arctic Ecology – A Paleoenvironmental Perspective 23
Michael Pisaric and John P. Smol

2.1 Introduction 23

2.2 The Distant Past 25

2.2.1 Bones, DNA, and Megafauna 26

2.2.2 Beringian Biota 27

2.2.3 Ancient DNA 29

2.3 Rings and Things: Examining Paleoenvironmental and Paleoclimatic Change Using Dendrochronology 30

2.3.1 Dendrochronology in Action: Examples from the Field 32

2.4 Lake Sediments: Continuous Archives of Environmental Change 33

2.5 Paleolimnology and Arctic Climate Change 37

2.5.1 Subfossil Pollen, Stomata, and Macrofossils for Tracking Vegetation Change 38

2.5.2 Charcoal and Past Wildfires 39

2.5.3 Using Past Assemblage Changes in Lake Biota to Reconstruct Past Climatic Trends 39

2.5.4 Using Paleolimnology to Study the Source and Fate of Contaminants 43

2.5.5 Linking Paleolimnology and Archeology: Tracking the Limnological Effects of Early Peoples in the Arctic 48

2.6 Concluding Remarks 49

References 50

3 Climate Change in the Arctic 57
Edward Hanna, Joseph E. Nolan, James E. Overland, and Richard J. Hall

3.1 Introduction to Arctic Climates – Datasets Available for Analyzing Climate Change 57

3.2 Atmospheric Aspects of Arctic Climate Change: Arctic Amplification and Global Warming, Changes in Air Temperature and Precipitation, and Changes in Atmospheric Circulation 59

3.3 Oceanic Aspects of Arctic Climate Change, Including Surface and Deep Ocean Circulation Changes 61

3.4 Climate Change Impacts on Arctic Sea Ice and Greenland Ice Sheet – The Unprecedented Recent Decline in Late Summer Sea-Ice Cover and Record Greenland Ice Sheet Surface Melt and Mass Loss 65

3.5 Feedbacks in the Arctic Climate System and Global Impacts – the Ice/Albedo Feedback and Ice Insulation Feedbacks – the “Warm Arctic, Cold Continents” Hypothesis 71

3.6 Concluding Remarks 73

References 75

4 Arctic Permafrost and Ecosystem Functioning 81
Torben R. Christensen

4.1 Permafrost and Ecosystems in the Arctic 81

4.2 Permafrost Shapes the Landscape 83

4.2.1 Permafrost Specific Landforms and Their Importance for Ecosystems 83

4.2.2 Permafrost Specific Landforms and Effects of a Changing Climate 86

4.3 The Biology of Permafrost 87

4.3.1 Microbes 87

4.3.2 Vegetation 88

4.4 Ecosystem Function – Carbon Cycling in Permafrost Environments 91

4.4.1 General Carbon Cycling 91

4.4.2 Methane Emissions 92

4.5 Concluding Remarks 94

References 95

5 Arctic Tundra 103
John Hobbie, Gaius Shaver, Toke Thomas Høye, and Joseph Bowden

5.1 Distribution and Description of Arctic Tundra 103

5.2 Tundra Organisms: A Typical Food Web 105

5.3 Flora and Fauna: Diversity and Communities 106

5.4 Primary Production and Organic Matter Stocks in the Low and High Arctic 110

5.5 Primary Production and Organic Matter Stocks 112

5.6 Adaptations to the Arctic Tundra 112

5.6.1 Plant Adaptations 112

5.6.2 Microbial Activity and Soil Carbon and Nitrogen 115

5.6.3 Invertebrates: Diversity, Freeze-Tolerance, and Freeze-Avoidance 116

5.6.4 Vertebrates of the Tundra: Wintertime Survival Strategies 117

5.7 Reproductive Strategies 118

5.8 Populations and Communities of the Tundra 120

5.8.1 Diversity and Interactions: The Case of Beringia 120

5.8.2 Development of Arctic Tundra Food Webs: Complexity, Insects 121

5.8.3 Belowground Arctic Food Web: Bacteria, Mycorrhizal Fungi, Nitrogen, and Carbon Cycling 122

5.9 Tundra Ecosystem Analysis 123

5.9.1 Why Nutrient Limitation? 123

5.9.2 Nitrogen Budget: Pools of Nitrogen, Rates of Transport, and Transformations 124

5.9.3 Carbon Budget: Pools, Gross Photosynthesis and Respiration, Accumulation and Feedbacks 126

5.9.4 Insights from Manipulation Experiments: Control of Net Primary Production and Herbivory by Nutrients, Light, and Heat 126

5.10 Expected Future Changes and Responses in Arctic Tundra 128

5.10.1 Effects of Increased Shrubs 128

5.10.2 Pest Outbreaks, Changes in Phenology and Species Interactions 129

References 130

6 Ecology of Arctic Glaciers 133
Alexandre M. Anesio and Johanna Laybourn-Parry

6.1 Introduction 133

6.2 The Biodiversity and Food Webs of Glacial Habitats 136

6.2.1 Ice Shelves 136

6.2.2 Supraglacial or Cryolakes 138

6.2.3 Cryoconite Material, Cryoconite Holes, and Wet Ice Surfaces 139

6.2.4 Snow on the Surface of Ice 141

6.2.5 Life Within Ice 141

6.2.6 Life in Subglacial Environments 143

6.3 Quantification of Microbial Processes in Glaciers and Export of Material to Adjacent Ecosystems 144

6.3.1 Supraglacial Habitats: Ice Shelf Lakes, Ponds, Cryoconites 144

6.3.2 Subglacial Habitats 149

6.4 Anthropogenic Impacts 151

References 152

7 Ecology of Arctic Lakes and Ponds 159
Erik Jeppesen, Kirsten S. Christoffersen, Milla Rautio, and Torben L. Lauridsen

7.1 Introduction 159

7.2 Physical and Chemical Characteristics of Arctic Lakes and Ponds 160

7.3 Biological Communities and Production 162

7.3.1 Phytoplankton and Phytobenthos 162

7.3.2 Macrophytes 164

7.3.3 Microbial Loop 165

7.3.4 Zooplankton and Zoobenthos 165

7.3.5 Fish 168

7.3.6 Food Webs 169

7.4 Global Climate Change and Arctic Lakes 171

References 174

8 Ecology of Arctic Streams and Rivers 181
Alexander D. Huryn

8.1 Introduction 181

8.1.1 What Is an Arctic River? 181

8.2 A Primer on Stream Ecology: General and Arctic Perspectives 183

8.2.1 The Longitudinal Dimension 184

8.2.2 The Vertical Dimension 202

8.2.3 The Lateral Dimension 207

8.3 Concluding Remarks 209

References 211

9 Ecology of Arctic Pelagic Communities 219
Malin Daase, Jørgen Berge, Janne E. Søreide, and Stig Falk-Petersen

9.1 Introduction 219

9.2 The Arctic Marine Highways: The Transpolar Drift and the Interconnected Current Systems 220

9.3 Members and Key Players of Arctic Pelagic Communities 224

9.3.1 At the Base – Primary Producers and Microbial Communities 224

9.3.2 In the Middle – Resident Consumers and Life Strategies of Arctic Zooplankton 229

9.3.3 At the Top – Pelagic Predators 239

9.4 A Lipid-Driven Food Chain 241

9.5 Effects of Climate Change 242

9.5.1 Timing 243

9.5.2 Changes in Species Distribution 243

References 246

10 Ecology of Arctic Sea Ice 261
C. J. Mundy and Klaus M. Meiners

10.1 Introduction to Sea Ice 261

10.2 Types of Habitats 262

10.3 Food Webs and Carbon Flow 264

10.4 Physical Environment 268

10.5 Colonization of Sea Ice and Winter Survival 270

10.6 Adaptations to and Relationships with Environmental Conditions 272

10.6.1 Temperature and Salinity 272

10.6.2 Space and Permeability 275

10.6.3 Light 276

10.7 Climate Change and the Ice-Associated Ecosystem 278

References 279

11 Ecology of Arctic Shallow Subtidal and Intertidal Benthos 289
Paul E. Renaud, Jan Marcin Węsławski, and Kathleen Conlan

11.1 Introduction 289

11.2 The Physical Environment 290

11.2.1 Temperature 290

11.2.2 Light 290

11.2.3 Waves 291

11.2.4 Ice Cover 291

11.2.5 Freshwater Discharge and Salinity 293

11.3 Biomes 294

11.3.1 Origins and Distribution of Sediments 294

11.3.2 Soft-Sediment Communities 295

11.3.3 Hard Substrate 297

11.3.4 Vegetated Substrate 300

11.4 Disturbance Regimes and Succession 302

11.4.1 Ice Scour 302

11.4.2 Strudel Scour 304

11.4.3 Natural Gas Seepage and Petroleum Extraction 305

11.4.4 Large-Mammal Feeding Pits 305

11.4.5 Recolonization of Arctic Benthos 306

11.4.6 Human Impacts 307

11.5 Trophic Interactions 308

11.5.1 Feeding Strategies in Arctic Shallow Benthos 308

11.5.2 Food Sources for Benthic Fauna 309

11.5.3 Benthos as a Food for Top Predators in the Arctic 310

11.5.4 Carbon and Nutrient Cycling 314

11.6 Reproduction in Coastal Benthos 315

11.7 Effects of Global Climate Change on Shallow Arctic Benthos 316

11.7.1 Reduced Ice Cover 319

11.7.2 Documented Effects on Natural Systems in the Intertidal Zone 319

11.7.3 Coastal Erosion 319

References 320

12 Ecology of Arctic Shelf and Deep Ocean Benthos 325
Monika Kędra and Jacqueline M. Grebmeier

12.1 Introduction 325

12.2 The Physical Environment 326

12.2.1 Light 327

12.2.2 Temperature 327

12.2.3 Sea Ice 328

12.2.4 Sediment Characteristics 328

12.3 Biodiversity, Community Structure, and Functioning of Shelf and Deep Sea Benthos 330

12.3.1 Benthic Definitions 330

12.3.2 Brief Overview of Major Taxa in Benthic Communities 331

12.3.3 Biodiversity 335

12.3.4 Functional Diversity 337

12.3.5 Arctic Commercial Benthic Species 338

12.4 Productivity and Food Webs of Shelf and Deep Sea Benthos 339

12.4.1 Primary Production and Food Sources 339

12.4.2 Pelagic–Benthic Coupling 341

12.4.3 Benthic Community Structure and Food Webs 343

12.4.4 Benthic Communities as a Food Source for Benthic-Feeding Upper Trophic Levels 346

12.5 Impact of Global Climate Change on Shelf and Deep Sea Benthic Communities 348

References 349

13 Fat, Furry, Flexible, and Functionally Important: Characteristics of Mammals Living in the Arctic 357
Niels M. Schmidt, Olivier Gilg, Jon Aars, and Rolf A. Ims

13.1 Introduction 357

13.2 The Mammal Assemblage in the Arctic Today 358

13.2.1 Terrestrial Mammals 358

13.2.2 Herbivores 358

13.2.3 Predators 359

13.2.4 Marine Mammals 360

13.3 Arctic Mammals and Adaptations to Life in the Arctic 366

13.3.1 Fur, Fat and Extremities 367

13.3.2 Behavioral Adaptations to Life in the Arctic 368

13.4 The Role of Mammals in Arctic Ecosystems 369

13.4.1 Removal of Plant Material by Terrestrial Herbivores 371

13.4.2 Transport of Nutrients and Seeds by Arctic Mammals 372

13.4.3 Mammal Predator–Prey Dynamics 374

13.5 The Future for Arctic Mammals in a Changing Climate 374

13.6 Concluding Remarks 377

References 377

14 Ecology of Arctic Birds 385
Anthony D. Fox

14.1 Introduction: The Bird Species and Their Feeding Ecology 385

14.2 Traveling to Breed 386

14.3 Long Distance Migrations 388

14.4 Reproduction 389

14.5 Survival 394

14.6 Population Change 396

14.7 Climate Change 397

14.8 Endangered Species 399

14.9 Concluding Remarks 402

References 403

15 Arctic Ecology, Indigenous Peoples and Environmental Governance 409
Mark Nuttall

15.1 Introduction 409

15.2 The Impacts of Social and Environmental Change 410

15.3 Traditional Ecological Knowledge and Wildlife Management 413

15.4 Arctic Ecology and Community-Based Monitoring 415

15.5 Indigenous Peoples and Environmental Policy: The Case of the Inuit Circumpolar Council 418

15.6 Concluding Remarks 419

References 420

Index 423

About the Editor

DAVID N. THOMAS is Professor of Arctic Ecosystem Research in the Faculty of Biological and Environmental Sciences, University of Helsinki. Previously he spent 24 years in the School of Ocean Sciences, Bangor University, Wales, where he is now an Honorary Professor. He studies marine systems, with a particular emphasis on sea ice and land-coast interactions in the Arctic and Southern Oceans as well as the Baltic Sea. He also edited a related book: Sea Ice, 3rd Edition (2017), which is also published by Wiley-Blackwell.