The Effects of Global Warming on Marine Ecosystems at the Poles PERIL AT THE POLES By: Amber Mueller Global Warming: the increase in the average temperature of the Earth’s near-surface air and oceans due to the increase of greenhouse gasses in the atmosphere, and its projected continuation The Poles: Includes: the Arctic – Arctic Ocean, parts of Canada, Greenland, Russia, the U.S(Alaska), Iceland, Norway, Sweden, and Finland And the Antarctic – Surrounded by the Southern Sea Protected by the Antarctic Treaty The Cryosphere: Portions of the Earth’s surface where water is in solid form Importance? Ice reflects sunlight, keeping temps BUT when the ice melts, water absorbs 4 times as much light, heating the ice in the water and thus heating the poles and destroying the Cyosphere Water, Water, EVERYWHERE! The Southern Ocean Semi-frozen ice in combo with salt water edge promotes remarkable growth of microscopic plankton = base of ecosystem Thrive under ice (only) I RULE YOU Food source for Krill ALL! The Great Southern Ocean Krill cash cow ($$$) 60-70% of southern hemisphere krill pop Before 1939- stable krill pop Since 1976- nearly 40% decrease per decade Chain of Life… Increase of Jelly-like Salps modest dietary needs devoid of nutrients not a food source to any marine birds or mammals Say Goodbye.. “Penguins, albatrosses, seals and whales are prone to krill shortages”- Atkinson Ice and Krill sea ice volume was stable between 1840 and 1950 began decreasing after that -20% krill pop numbers coincided climate change is a profound threat to the most productive ocean in the world. Impact? Emperor penguin population is half of what it was thirty years ago Adelie penguins have declined 70%. Impact… southern right whales need to feed on winter krill in order to have energy to swim to mating grounds humpback whales, seals, and penguins will be on the verge of extinction A Sea of Jelly Salps!!! The Arctic: Home of about 4 million better studied Winters in Alaska are 4-5 degrees warmer than they were 30 years ago Visible Changes Atlantic hair grass is growing at higher altitudes spruce bark beetle killed 40 million trees in southern Alaska Worst insect destruction in NA history Forest Encroachment Overall decrease in population of Birds and Mammals The Spruce Beetle: Population is usually controlled by cold winters Mild temperatures allow the species to survive and destroy More Bugs… Spruce budworms are also a threat female budworms lay 50% more eggs at 77 degrees than at 59 degrees. The Arctic Climate Impact 2004- the Arctic Climate Impact Assessment As the forest encroaches northward to the Arctic Sea the tundra will be destroyed Predicted that at least 50% of suitable habitat will be lost by the end of the century Bye Bye Birdie Several hundred million birds migrate to the treeless tundra to breed When the tundra is gone great flocks will be destroyed The Collard Lemming Represent winter endurance and resilience superbly adapted to life in cryosphere Only rodents whose coat turns white in winter and claws turn to two-pronged shovels for snow tunneling habitat the tundra they will go extinct by end of century Impact on Caribou: increase in rain causes lichens (their food source) to freeze over changed snowfall patterns kill calves as they try to migrate numbers have dropped from plentiful 26,000 in 1961 to 1,000 in 1997 The Ringed Seal most abundant mammal in far north yet if the temp isn’t cold enough for snow to fall they cant make their dens cant breed many have left for Siberia leaving the polar bears to starve More Seals… Harp seals are similar the number of ice free years often exceeds the female reproductive life Gulf of St. Lawrence population is almost extinct with no hope of recovery. Ringed, ribbon, bearded seals, and walrus all live under the same threat The Great Nanuk can survive at the harshest of temperatures Have been spotted within 100 miles from the true North pole! Only thing that stops them is lack of food Polar Bears: long term study of 1,200 individuals average of 15% skinnier than a decade ago feeding season has become too short potential food has migrated Each year starving females give birth to fewer cubs Polar Bear Breeding Twenty years ago a mother could support triplets and about half of all cubs born survived Now the survival ratio is 1:20 Increasing winter rains collapse dens killing mothers and cubs More Threats: Early break up of ice can separate denning and feeding areas b/c most cubs can’t swim far enough Who Cares? Usually a healthy, well fed polar bear eats the fat off a seal, leaving the rest to the arctic fox, the raven, Thayer’s and ivory gulls some parts of the year these animals depend solely on polar bears scraps Chain, Chain, Chain… Ivory Gulls have decreased in pop 90% over last 20 years due to habitat disappearance and lack of food What does all of this Mean? The Arctic Realm will be replaced by polar deserts and encroaching forests more forests = more heat they will trap (ice reflects light, trees absorb light ) which will heat the planet ever more swiftly Going, Going, Gone The Cryosphere will vanish and with it all the animals of the Arctic and Antarctic will become extinct. UNLESS WE DO SOMETHING ABOUT IT!
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