Antarctic Ecosystems: An Extreme Environment in a Changing World

Since its discovery Antarctica has held a deep fascination for biologists. Extreme environmental conditions, seasonality and isolation have lead to some of the most striking examples of natural selection and adaptation on Earth. Paradoxically, some of these adaptations may pose constraints on the ability of the Antarctic biota to respond to climate change. Parts of Antarctica are showing some of the largest changes in temperature and other environmental conditions in the world. In this volume, published in association with the Royal Society, leading polar scientists present a synthesis of the latest research on the biological systems in Antarctica, covering organisms from microbes to vertebrate higher predators. This book comes at a time when new technologies and approaches allow the implications of climate change and other direct human impacts on Antarctica to be viewed at a range of scales; across entire regions, whole ecosystems and down to the level of species and variation within their genomes. Chapters address both Antarctic terrestrial and marine ecosystems, and the scientific and management challenges of the future are explored.  

Table of Contents:
Contributors, xi INTRODUCTION: ANTARCTIC ECOLOGY IN A CHANGING WORLD, 1 Andrew Clarke, Nadine M. Johnston, Eugene J. Murphy and Alex D. Rogers Introduction, 1 Climate change, 2 The historical context, 3 The importance of scale, 3 Fisheries and conservation, 4 Concluding remarks, 6 References, 6 PART 1 TERRESTRIAL AND FRESHWATER HABITATS, 11 1 SPATIAL AND TEMPORAL VARIABILITY IN TERRESTRIAL ANTARCTIC BIODIVERSITY, 13 Steven L. Chown and Peter Convey 1.1 Introduction, 13 1.2 Variation across space, 16 1.2.1 Individual and population levels, 16 1.2.2 Species level, 18 1.2.3 Assemblage and ecosystem levels, 20 1.3 Variation through time, 25 1.3.1 Individual level, 26 1.3.2 Population level, 27 1.3.3 Species level, 29 1.3.4 Assemblage and ecosystem levels, 29 1.4 Conclusions and implications, 30 Acknowledgments, 31 References, 31 2 GLOBAL CHANGE IN A LOW DIVERSITY TERRESTRIAL ECOSYSTEM: THE MCMURDO DRY VALLEYS, 44 Diana H. Wall 2.1 Introduction, 44 2.2 The McMurdo dry valley region, 46 2.3 Above–belowground interactions, 46 2.4 The functioning of low diversity systems, 50 2.5 Effects of global changes on coupled above–belowground subsystems, 51 2.6 Temperature change: warming, 52 2.7 Temperature change: cooling, 54 2.8 Direct human influence: trampling, 54 2.9 UV Radiation, 55 2.10 Concluding remarks, 56 Acknowledgements, 56 References, 56 3 ANTARCTIC LAKES AS MODELS FOR THE STUDY OF MICROBIAL BIODIVERSITY, BIOGEOGRAPHY AND EVOLUTION, 63 David A. Pearce and Johanna Laybourn-Parry 3.1 The variety of antarctic lake types, 63 3.2 The physical and chemical lake environment, 66 3.3 The microbial diversity of antarctic lakes, 66 3.3.1 Methods for exploring Antarctic lake biodiversity, 67 3.3.2 Microbial groups, 69 3.3.3 Protists, 70 3.3.4 Crustacea, 72 3.4 Biogeography, 74 3.4.1 Spatial variation and the global ubiquity hypothesis, 74 3.4.2 Temporal variation and palaeolimnology, 75 3.5 Evolution, 76 3.5.1 Prokaryote physiology, 76 3.5.2 Eukaryote physiology, 77 3.6 Future perspectives, 78 3.7 Acknowledgement, 78 References, 78 PART 2 MARINE HABITATS AND REGIONS, 91 4 THE IMPACT OF REGIONAL CLIMATE CHANGE ON THE MARINE ECOSYSTEM OF THE WESTERN ANTARCTIC PENINSULA, 93 Andrew Clarke, David K. A. Barnes, Thomas J. Bracegirdle, Hugh W. Ducklow, John C. King, Michael P. Meredith, Eugene J. Murphy and Lloyd S. Peck 4.1 Introduction, 93 4.1.1 The oceanographic setting, 96 4.1.2 The historical context, 97 4.2 Predicted environmental changes along the western antarctic peninsula, 98 4.3 Environmental variability and ecological response, 100 4.3.1 Biotic responses to climate change: some general points, 102 4.4 Responses of individual marine species to climate change, 102 4.4.1 Acclimation and evolutionary responses to environmental change in antarctic marine organisms, 104 4.5 Community level responses to climate change, 106 4.6 Ecosystem level responses to climate change, 107 4.7 What biological changes have been observed to date?, 109 4.8 Concluding remarks, 110 Acknowledgements, 110 References, 111 5 THE MARINE SYSTEM OF THE WESTERN ANTARCTIC PENINSULA, 121 Hugh Ducklow, Andrew Clarke, Rebecca Dickhut, Scott C. Doney, Heidi Geisz, Kuan Huang, Douglas G. Martinson, Michael P. Meredith, Holly V. Moeller, Martin Montes-Hugo, Oscar Schofield, Sharon E. Stammerjohn, Debbie Steinberg and William Fraser 5.1 Introduction, 121 5.2 Climate and ice, 123 5.2.1 Surface air temperature, 123 5.2.2 Sea ice, 123 5.2.3 Climate co-variability, 125 5.3 Physical oceanography, 127 5.4 Nutrients and carbon, 130 5.4.1 Nutrients and UCDW intrusions, 130 5.4.2 Carbon cycle, 131 5.4.3 Dissolved organic carbon, 132 5.4.4 Sedimentation and export, 133 5.5 Phytoplankton dynamics, 134 5.5.1 Seasonal scale dynamics, 134 5.5.2 Role of light, 134 5.5.3 Role of nutrients, 136 5.5.4 Annual variability in phytoplankton, 137 5.6 Microbial ecology, 138 5.7 Zooplankton, 140 5.7.1 Community composition and distribution, 140 5.7.2 Long-term trends and climate connections, 142 5.7.3 Grazing and biogeochemical cycling, 142 5.8 Penguins, 143 5.8.1 Contaminants in penguins, 145 5.9 Marine mammals, 146 5.10 Synthesis: food webs of the wap, 147 5.11 Conclusions, 148 Acknowledgements, 149 References, 149 6 SPATIAL AND TEMPORAL OPERATION OF THE SCOTIA SEA ECOSYSTEM, 160 E.J. Murphy, J.L. Watkins, P.N. Trathan, K. Reid, M.P. Meredith, S.L. Hill, S.E. Thorpe, N.M. Johnston, A. Clarke, G.A. Tarling, M.A. Collins, J. Forcada, A. Atkinson, P. Ward, I.J. Staniland, D.W. Pond, R.A. Cavanagh, R.S. Shreeve, R.E. Korb, M.J. Whitehouse, P.G. Rodhouse, P. Enderlein, A.G. Hirst, A.R. Martin, D.R. Briggs, N.J. Cunningham and A.H. Fleming 6.1 Introduction, 160 6.2 Oceanography and sea ice, 163 6.2.1 Upper-ocean circulation and characteristics in the Scotia Sea, 163 6.2.2 Physical variability and long-term change, 167 6.3 Nutrient and plankton dynamics, 168 6.4 Krill in the scotia sea food web, 171 6.4.1 Krill distribution in the Scotia Sea, 171 6.4.2 Krill growth and age in the Scotia Sea, 173 6.4.3 Krill reproduction and recruitment in the Scotia Sea, 174 6.4.4 Krill – habitat interactions in the Scotia Sea, 177 6.4.5 Krill population variability and change in the Scotia Sea, 180 6.4.6 Krill in the Scotia Sea food web, 183 6.5 Food web operation, 184 6.5.1 Trophic links, 184 6.5.2 Spatial operation of the food web, 189 6.6 Ecosystem variability and long-term change, 192 6.7 Concluding comments, 195 Summary, 196 Acknowledgements, 197 References, 197 7 THE ROSS SEA CONTINENTAL SHELF: REGIONAL BIOGEOCHEMICAL CYCLES, TROPHIC INTERACTIONS, AND POTENTIAL FUTURE CHANGES, 213 Walker O. Smith, Jr., David G. Ainley, Riccardo Cattaneo-Vietti and Eileen E. Hofmann 7.1 Introduction, 213 7.2 Physical setting, 214 7.3 Biological setting, 219 7.3.1 Lower trophic levels, 219 7.3.2 Mid-trophic levels, 225 7.3.3 Fishes and mobile predators, 226 7.3.4 Upper trophic levels, 227 7.3.5 Benthos, 229 7.4 Food web and biotic interactions, 230 7.5 Conclusions, 232 7.5.1 Uniqueness of the Ross Sea, 232 7.5.2 Potential impacts of climate change, 233 7.5.3 Conservation and the role of commercial fishing activity in the Ross Sea, 234 7.5.4 Research needs and future directions, 235 Acknowledgements, 235 References, 235 8 PELAGIC ECOSYSTEMS IN THE WATERS OFF EAST ANTARCTICA (30 E–150 E), 243 Stephen Nicol and Ben Raymond 8.1 Introduction, 243 8.2 The region, 245 8.2.1 The east (80 E–150 E), 245 8.2.2 The west (30 E–80 E), 247 8.3 Ecosystem change off east antarctica, 251 Summary, 251 References, 252 9 THE DYNAMIC MOSAIC, 255 David K.A. Barnes and Kathleen E. Conlan 9.1 Introduction, 255 9.2 Historical and geographic perspectives, 256 9.3 Disturbance, 257 9.3.1 Ice effects, 258 9.3.2 Asteroid impacts, 260 9.3.3 Sediment instability and hypoxia, 261 9.3.4 Wind and wave action, 261 9.3.5 Pollution, 262 9.3.6 UV irradiation, 263 9.3.7 Volcanic eruptions, 263 9.3.8 Trawling, 264 9.3.9 Non-indigenous species (NIS), 264 9.3.10 Freshwater, 265 9.3.11 Temperature stress, 265 9.3.12 Biological agents of physical disturbance, 266 9.4 Colonisaton of antarctic sea-beds, 266 9.4.1 Larval abundance, 266 9.4.2 Hard substrata, 266 9.4.3 Soft sediments, 269 9.5 Implications of climate change, 276 9.6 Conclusion, 279 Acknowledgements, 280 References, 281 10 SOUTHERN OCEAN DEEP BENTHIC BIODIVERSITY, 291 A. Brandt, C. De Broyer, B. Ebbe, K.E. Ellingsen, A.J. Gooday, D. Janussen, S. Kaiser, K. Linse, M. Schueller, M.R.A. Thomson, P.A. Tyler and A. Vanreusel 10.1 Introduction, 291 10.2 History of antarctic biodiversity work, 293 10.3 Geological history and evolution of the antarctic, 294 10.3.1 Indian Ocean, 294 10.3.2 South Atlantic, 294 10.3.3 Weddell Sea, 295 10.3.4 Drake Passage and Scotia Sea, 296 10.4 Benthic composition and diversity of meio-, macro- and megabenthos, 296 10.4.1 Meiofauna, 297 10.4.2 Macrofaunal composition and diversity, 299 10.4.3 Megafaunal composition and diversity, 304 10.5 Phylogenetic relationships of selected taxa, 308 10.5.1 Foraminifera, 308 10.5.2 Isopoda, 308 10.5.3 Tanaidacea, 309 10.5.4 Bivalvia, 310 10.5.5 Polychaeta, 310 10.5.6 Cephalopoda, 310 10.6 Biogeography and endemism, 311 10.6.1 Porifera, 311 10.6.2 Foraminifera, 311 10.6.3 Metazoan meiofauna, 311 10.6.4 Peracarida, 312 10.6.5 Mollusca, 312 10.6.6 Echinodermata, 313 10.6.7 Brachiopoda, 313 10.6.8 Polychaeta, 313 10.6.9 Bryozoa, 313 10.7 Relationship of selected faunal assemblages to environmental variables, 313 10.7.1 Large-scale patterns with depth, 313 10.7.2 Patterns influenced by other environmental or physical factors, 317 10.7.3 Isopoda, 318 10.8 Similarities and differences between antarctic and other deep-sea systems, 318 10.8.1 The environment, 318 10.8.2 A direct comparison between the deep sea of the SO and the World Ocean, 319 10.8.3 Dispersal and recruitment between the SO and the rest of the world, 320 10.8.4 The special case of chemosynthetically-driven deep-sea systems, 320 10.9 Conclusions, 321 Acknowledgements, 321 References, 323 11 ENVIRONMENTAL FORCING AND SOUTHERN OCEAN MARINE PREDATOR POPULATIONS, 335 Phil N. Trathan, Jaume Forcada and Eugene J. Murphy 11.1 Climate change: recent, rapid, regional warming, 335 11.2 Using oscillatory climate signals to predict future change in biological communities, 337 11.3 Potential for regional impacts on the biosphere, 338 11.4 Confounding isues in identifying a biological signal, 339 11.5 Regional ecosystem responses as a consequence of variation in regional food webs, 340 11.6 Where biological signals will be most apparent, 340 11.7 The southwest atlantic, 341 11.8 The indian ocean, 344 11.9 The pacific ocean, 345 11.10 Similarities between the atlantic, indian and pacific oceans, 346 11.11 What ENSO can tell us, 347 11.12 Future scenarios, 349 References, 349 PART 3 MOLECULAR ADAPTATIONS AND EVOLUTION, 355 12 MOLECULAR ECOPHYSIOLOGY OF ANTARCTIC NOTOTHENIOID FISHES, 357 C.-H. Christina Cheng and H. William Detrich III 12.1 Introduction, 357 12.2 Surviving the big chill – notothenioid freezing avoidance by antifreeze proteins, 358 12.2.1 Freezing challenge in frigid Antarctic marine environment, 358 12.2.2 Historical paradigm of teleost freezing avoidance, 360 12.2.3 Paradigm shift I: the ‘larval paradox’, 360 12.2.4 Paradigm shift II: liver is not the source of blood AFGP in notothenioids, 362 12.2.5 Gut versus blood – importance of intestinal freeze avoidance, 363 12.2.6 Non-hepatic source of plasma AFGP, 364 12.2.7 Alterations in environments and dynamic evolutionary change in notothenioid AFGP gene families, 364 12.2.8 Summary comments – antifreeze protein gain in Antarctic notothenioid fish, 367 12.3 Haemoprotein loss and cardiovascular adaptation in icefishes – dr. no to the rescue?, 367 12.3.1 Vertebrates without haemoglobins – you must be kidding!, 367 12.3.2 Haemoprotein loss in icefishes: an evolutionary perspective, 368 12.3.3 Cellular correlates of haemoprotein loss, 370 12.3.4 The icefish cardiovascular system, 371 12.3.5 Compensatory adjustment of the icefish cardiovascular system in a regime of reduced interspecific competition? Enter Dr. NO, 371 12.3.6 Haemoproteins, NO metabolism, and icefish evolution, 372 12.3.7 Icefishes and erythropoietic gene discovery, 372 12.3.8 Summary comments: haemoprotein loss in Antarctic icefishes, 374 12.4 Concluding remarks, 374 Acknowledgements, 374 Dedication, 374 References, 374 13 MECHANISMS DEFINING THERMAL LIMITS AND ADAPTATION IN MARINE ECTOTHERMS: AN INTEGRATIVE VIEW, 379 Hans O. P€ortner, Lloyd S. Peck and George N. Somero 13.1 Introduction: climate-dependent evolution of antarctic fauna, 379 13.2 Phenomena of thermal specialization and limitation, 382 13.2.1 Molecular and membrane aspects, 383 13.2.2 Genomic aspects: gene expression and loss of genetic information, 390 13.2.3 From molecular to systemic aspects: thermal limitation, 393 13.2.4 From molecular to systemic aspects: thermal adaptation of performance capacity, 397 13.2.5 Ecological implications, 399 13.2.6 Integration of phenomena: concepts, results and perspectives, 405 Acknowledgements, 409 References, 409 14 EVOLUTION AND BIODIVERSITY OF ANTARCTIC ORGANISMS, 417 Alex D. Rogers 14.1 Introduction, 417 14.2 The antarctic biota, 418 14.3 The break-up of gondwana and the evolution of the southern hemisphere biota, 420 14.3.1 Vicariance versus dispersal, 420 14.3.2 Dispersal mechanisms, 421 14.4 The evolution and biodiversity of the terrestrial sub-antarctic and antarctic biota, 423 14.4.1 Plants, 423 14.4.2 Animals, 427 14.5 The marine environment, 432 14.5.1 Biogeography and macroevolution, 432 14.5.2 Notothenioid fish, 432 14.5.3 Birds, 435 14.5.4 Marine invertebrates, 436 14.5.5 The molecular ecology and phylogeography of the marine biota, 437 14.5.6 Patterns of genetic variation in marine species, 448 14.6 Antarctica: a climatic crucible of evolution, 450 14.7 The historical constraints on adaptation to present climate change, 453 14.8 Future directions for research, 453 References, 454 PART 4 CONSERVATION AND MANAGEMENT ASPECTS, 469 15 BIOGEOGRAPHY AND REGIONAL CLASSIFICATIONS OF ANTARCTICA, 471 P. Convey, D.K.A. Barnes, H.J. Griffiths, S.M. Grant, K. Linse and D.N. Thomas 15.1 Introduction, 471 15.2 Historical background, 474 15.2.1 Physical regions in the marine environment, 474 15.2.2 Smaller-scale regionalization within the Antarctic marine environment, 474 15.2.3 Physical regions in the littoral environment, 475 15.2.4 Physical regions in the terrestrial environment, 475 15.3 Data availability, 476 15.4 Different realms in the marine and terrestrial environments, 477 15.4.1 Pelagic realm, 477 15.4.2 Sea ice, 478 15.4.3 Benthic realm, 479 15.4.4 The terrestrial environment, 479 15.4.5 Biogeographical patterns in the terrestrial environment, 480 15.4.6 Biogeographic patterns in the marine environment, 481 15.5 Overview, 485 Acknowledgements, 486 References, 486 16 CONSERVATION AND MANAGEMENT OF ANTARCTIC ECOSYSTEMS, 492 Susie M. Grant, Pete Convey, Kevin A. Hughes, Richard A. Phillips and Phil N. Trathan 16.1 Introduction, 492 16.2 Legal frameworks for conservation and management, 495 16.2.1 Early regulation of marine living resource harvesting, 495 16.2.2 The Antarctic Treaty System, 497 16.2.3 Other (non-ATS) agreements and tools relevant to conservation and management, 500 16.3 Conservation and management measures, 502 16.3.1 Pollution and local disturbance, 502 16.3.2 Biosecurity and non-native species, 505 16.3.3 Conservation and management of marine living resources, 505 16.3.4 Conservation of other individual species, 507 16.3.5 Protected areas, 509 16.4 Conservation science and monitoring, 512 16.5 Future challenges, 515 16.6 Conclusions, 520 Acknowledgements, 521 References, 521 Index, 526