The spotlight is on the Arctic region. Crumbling glaciers, thawing permafrost and the vanishing sea ice cover are phenomena frequently discussed in the media. They are clear signs of the intense warming of the Arctic ecosystem. The dramatic decline in sea ice has consequences not only for the microorganisms, plants, animals and peoples that live there, but also for the climate at the middle latitudes. Inspired by their years of scientific research and experience in the field, the authors present unique photographic material and discuss the processes and the impact of climate warming in the polar region.
The polar bear is the symbol par excellence of the unique sea ice ecosystem. The authors explore the life, past and future of this top predator. Can this super-specialist still adapt? Is its survival threatened or not?
The Future Polar Bear provides the necessary tools to put media reports about the Arctic, climate change, sea ice and the Polar Bear into context.
About the authors 9
Foreword by Robert Christopherson 11
Acknowledgements 13
1. Introduction: The lure of the icy seascapes 17
2. The Arctic’s geography in a nutshell 23
An ocean surrounded by land 23
Where are the Arctic’s boundaries? 25
The meaning of the Arctic Circle 26
How big is the Arctic area? 27
3. The Arctic climate 31
Less solar radiation, more reflection 31
The radiation balance and the supply of heat 32
The more northernly, the colder and dryer 33
Where do we find the lowest temperatures? 35
4. Climate change in the Arctic 39
Why is the increase in temperature more evident in the Arctic? 39
Climate change and the Arctic people 42
The influence of changes in the Arctic on the climate at lower latitudes 43
Is what is happening in the Arctic really that bad? 45
5. The sea ice 49
About water 50
How sea water freezes 50
From ice crystal to first-year pack ice 52
Multi-year pack ice 53
Movements of sea ice in space and time 57
Temperature gradient and salt concentrations in the ice 58
Open water amid sea ice: the polynya 60
Freshwater mountains in the sea: icebergs 61
6. Algae and grazers in the sea ice ecosystem 65
A piece of ice alive with all kinds of beings 65
Single-celled life as the basis of the sea ice ecosystem 66
The growth and production of algae in the sea ice 68
Sea ice algae also need nutrients 69
The ice algae bloom and their release from the melting ice 69
Sea algae play a role in atmospheric processes 70
The grazers of the sea ice algae 70
Two separate algae blooms fuel the grazing animals 71
Zooplankton as a link between algae and higher trophic levels 71
Calanus copepods as bulk food for fish, birds, whales 72
Copepods as food for the Little Auk 75
A small fish with a great influence: the Polar Cod 76
A companion to warming: the acidifcation of the ocean 79
7. How do birds and mammals cope with the cold? 83
Stay or go 83
Heat production and brown fat 84
The difficult balance between heat loss and production 86
Thermal bridges and insulation 86
Sea mammals need a thick fat layer 87
A heat exchanger 87
Body volumes and surfaces 88
The meanings of colours 89
Hibernation? 89
8. Sea ice loss and Arctic seabirds 93
Arctic ice-associated seabirds 93
The Spectacled Eider 94
Least Auklet 94
Crested Auklet 95
The Black Guillemots of Cooper Island 96
Brünnich’s Guillemots 100
The elusive Ivory Gull 101
Ross’s Gull: the mystery of the Arctic 104
9. Impacts of declining sea ice on Arctic marine mammals 109
Walrus: the tooth walker 109
Lack of sea ice 111
Ringed seals 113
Bearded seals 115
Harp seals 117
Moving north? 119
Whales of the Arctic sea ice 119
Bowhead Whale 120
Beluga or White Whale 121
The Narwhal: unicorn of the ice 122
Reduced sea ice: more assaults 122
10. Apex predator: the Polar Bear 127
Taxonomy 128
The early years 129
Speciation is underway 131
The ‘ice bear’ cometh 132
Fossil record, classifcation and taxonomy 133
Surviving the earlier warmer periods 137
11. Population ups, downs & whereabouts 147
Where do Polar Bears live in this seasonal landscape? 149
The subpopulation regions: the bears’ home ranges 151
Roaming the regions 153
Svalbard Archipelago in the Barents Sea 154B
Bears of the Greenland pack ice 158
Hudson Bay: the best-studied Polar Bears in the Arctic 159
The Beaufort sea and the Chukchi Sea Polar Bears 166
12. Reproduction, denning & cub rearing 173
The mating season 174
Pregnant bears move ashore and make dens 178
Declining and unstable pack ice 180
Birthing and external pregnancy 184
Leaving the den and the hunt for food 186
Mother bear as teacher 189
13. Hunting strategies and food 197
Top of the menu: seals 197
Hunting methods on the ice 198
The still hunt 199
Stalking on the ice 201
Aquatic stalking 203
Sense of smell 206
Hunt timing issues 206
Alternative food sources 209
Potential food trapped in the ice 211
Bears stranded on land where living is not easy 213
Food at a dead end 218
14. Additional assaults on the Polar Bear 223
Contamination 223
Why is a threatened species still harvested? 227
The Future Polar Bear: a reflection 231
References 234
Louis Beyens and Rinie van Meurs each have more than thirty years of experience in the polar regions as scientists and expedition guides. Beyens is a professor emeritus at the University of Antwerp and specializes in polar ecosystems. As an expedition leader, Van Meurs is fascinated by the animal life in the sea ice and is a passionate follower of the polar bear.