polar ecology. bhopal, india minamata, japan chernobyl, ussr toxic events
TRANSCRIPT
“Sea ice is a key component in structuring polar environments. Beside its important role as a platform for marine mammals and birds, it serves as a habitat for a unique highly specialized community of bacteria, algae, protozoa and metazoa, which contribute to the biogeochemical cycles of the Arctic and Antarctic seas.’’
Not uniformocean heat storageLight blue constant Yellow to white most rapid riseSlow down in the sub-polar gyreThermohaline circulation weakening?Major Extinctions
Warming water and melting land ice : mean sea level up 4.5 cm from1993 to 2008
Antarctic vs Arctic Ocean • 50 to 70 degrees S• 35-38 million sq km• Narrow shelf, few islands• Shelf 400-600 m• Open to 3 oceans• Circumpolar current• Vertical mixing high• Nutrient high continuously• High primary productivity• Little to no freshwater input • Salinity 34 ppt• High seasonal ice pack• Low benthos disturbance
• 70 to 80 degrees N• 14.6 million sq km• Broad shelf, archipelagos• Shelf 100-500 m• At Fram & Bering Straits• Transpolar• Little vertical mixing• Seasonally depleted• Moderate primary productivity• Extensive fluvial input• Salinity 31 ppt• Ice pack seasonally low• Extensive bottom disturbance
FIG. 1. Polyacrylamide gel of fluorescently labeled AFGPs from Antarctic notothenioid Dissostichus mawsoni (Dm) and Arctic cod Boreogadus saida (Bs) and the amino acid compositions of the three size groups of Arctic cod AFGPs. The two polar fishes show comparable size heterogeneity, especially AFGP 6-8
Convergent evolution of antifreeze glycoproteins in Antarcticnotothenioid fish and Arctic cod(repetitive sequenceygene duplicationysequence convergenceytrypsinogen)LIANGBIAO CHEN, ARTHUR L. DEVRIES, AND CHI-HING C. CHENG*
Number of fish species between Antarctic and Arctic
• Chondrichthyes• Salmoniformes• Myctophiformes• Gadiformes• Cottidae• Liparidae• Zoarcoidei• Nototheniodei• Pleuronectiformess
• 11 vs 26• 0 vs 32• 35 vs 7• 21 vs 44• 0 vs 44• 31 vs 17• 22 vs 67• 95 vs 0• 4 vs 28
Marine Mammals
• Mammals that use the sea in their natural history
• Has evolved 5-8 times• Extant groups
– Ceataceans– Sirineans– Pinnipeds– Sea Otter : Mustelidae, Enhydra lutris– Polar Bear : Ursidae, Ursus maritimus
Living at sea
• Can’t respire in water
• Heat loss greater
• Locomotion in denser medium
• Hearing: asymmetrical skull
• Low visibility
• Time spent in water varies with species
• Lack of freshwater
Adaptations
• Polar bears: not adapted for diving
• Sea otters: not accomplished divers
• Pinnipeds: great diving capabilities
• Sirenians: totally aquatics, decent diver
• Cetaceans: Most derived
Suborder Pinnipedia
• Otariidae (eared seals, 16 spp)– Shallow divers
• Odobenidae (walrus, 1 spp)
• Phocidae (true seals, 19 spp)
Order Cetacea60 to ~200,000 kg
• Baleen whales (mysticetes, 13 spp)– Balaenopteridae: 8 spp of rorqual whales– Balaenidae: 3 spp of right whale & bowhead– Neobalaenidae: 1 spp pygmy right whale– Eschrichtiidae: 1 spp gray whale
• Toothed whales (odontocetes, 70 spp)
Toothed whales (odontocetes)
• 10 families, 70 spp
• Physeteridae: sperm whale
• Monodontidae: beluga & narwhal
• Delphinidae: 35 spp dolphins, killer whale
• Phocoenidae: 6 spp porpoises