The Global 200 : a representation Approach to Conserving the Earth’s Distinctive Ecoregions
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- Temperate Shelf and Seas
PolarLow temperatures, low salinity, and extensive ice are typical of the polar ocean. Ice cover may be present in the form of extensive sheets or drift ice and icebergs carried by polar currents. This ice cover does not prevent light from penetrating waters below the surface. Thus, cold temperatures do not seem to limit diversity, but productivity may be limited by the lack of nutrients due to the cold temperatures. Ice provides important habitat in the form of breeding platform from which seals breed and search for food. Polar bears in the Arctic, and penguins in the Antarctic, also rely on the ice for habitat. Warm water upwellings create breaks in the ice. Not only are the corresponding ice-free areas nutrient-rich, but also they are often predictable year-to-year, providing habitat and access to food for seabirds and mammals.In terms of species assemblages, both the Arctic and Antarctic support resident and migratory mammals and birds, but the Arctic Ocean is characterized by a diversity of fish species while the Southern Ocean is not. Antarctica’s benthic (bottom dwelling) community has greater species richness and higher levels of endemism—including several species of “bloodless fish”—but fewer phyla are represented than in the Arctic. Crabs, sharks, most benthic fish and snails, large clams, and amphipods are present in the Arctic but missing from Antarctic Seas. AntarcticA ntarctic Peninsula & Weddell Sea [196] Geographic Location: Antarctic Peninsula & Weddell Sea Biodiversity Features: The Weddell Sea supports a rich marine ecosystem, where huge quantities of krill provide food for diverse populations of fish and marine mammals. The Weddell Sea also supports thriving colonies of penguins that lay their eggs and raise their young on the Antarctic Peninsula. The most diverse and productive Antarctic marine ecosystem Selected Species: Species include king penguin (Aptenodytes patagonicus), emperor penguin (A. forsteri), Weddell seal (Leptonychotes weddellii), crabeater seal (Lobodon carcinophagus), humpback whale (Megaptera novaeangliae), Southern right whale (Eubalaena australis) minke whale (Balaenoptera acutorostrata) and hourglass dolphin (Lagenorhynchus cruciger). Over 200 species of fish from various groups are known to live in Antarctica. The most numerous are species belonging to the Notothenioidei suborder. Within this suborder and endemic to Antarctic waters are the families of Nototheniidae, Harpagiferidae, Artedidraconidae, Bathydraconidae, and Channichthyidae—“bloodless fishes” that function with an absence of hemoglobin. General Threats: Overfishing, global warming, the weakening of the ozone layer, and pollution pose the greatest threats to the region. ArcticB ering Sea [197] – Canada, Russia, United States Geographic Location: Northern Pacific Ocean and western Arctic Ocean Biodiversity Features: The Bering Strait and associated islands are critical to marine life migrating to and from summering grounds in the Chukchi Sea and elsewhere in the Arctic Ocean. The region supports huge seabird populations, including nearly 2 million murres and auklets, and is home to one of the largest salmon runs in the world. There are also extensive kelp forests and eelgrass beds in coastal lagoons. One the most diverse and richest subpolar and polar marine ecosystems in the world Selected Species: The strait is used by 14 species of marine mammals, such as the endangered bowhead (Balaena mysticetus), several species of seals (Family, Phocidae), sea lions (Family Otariidae), and the Pacific walrus (Odobenus rosmarus). Salmonids include sockeye salmon (Oncorhynchus nerka), chinook (O. tshawytscha), steelhead (O. mykiss), and chum (O. keta). Other characteristic species include the red king crab (Paralithodes camtschatica) and yellowfin sole (Limanda aspera). General Threats: Overfishing, global warming, coastal mining, and pollution from shipping are the major threats to the region. B arents-Kara Sea [198] – Norway, Russia Geographic Location: Arctic Ocean north of Norway and Russia Biodiversity Features: These waters are highly productive, allowing inland tundra to be occupied by breeding seabirds; nesting colonies of migrating seabirds abound. Arctic terns breed here, before traveling 36,000 km to winter in Antarctica. Abundant marine mammal populations occur in this ecoregion. The ecoregion includes the Franz-Josef-Land nature reserve, the largest marine protected area on the Northern Hemisphere. One of the two richest and most productive regions of the Arctic Ocean Selected Species: Birds include little auk (Alle alle), barnacle goose (Branta leucopsis), pink-footed goose (Anser brachyrhynchus), Sabine's gull (Xema sabini), and white-billed diver (Gavia adamsii). Arctic cod (Boreogadus saida), flatfish (Order, Pleuronectiformes), smelt (Family, Osmeridae), polar bear (Ursus maritimus), bearded seal (Erignathus barbatus), walrus (Odobenus rosmarus), and narwhal (Monodon monoceros) live here. General Threats: Oil and gas development and fisheries impacts pose severe threats to the region. Radioactive materials dumped in the Barents-Kara Seas may have severely impacted the ecosystem, resulting in the deaths of millions of sea stars, shellfish, seals, porpoises and fishes. Temperate Shelf and SeasTemperate Shelf and Seas are highly productive regions supporting resident as well as migratory species during various life cycle stages. The relative shallowness of these regions (the continental shelf extends to an average maximum depth of 150 meters) leads to seasonal stratification of the water column based on temperature. Seasonality, the mixing of fresh and oceanic waters, and tides create temperate shelf and sea environments that are highly variable. Fish aggregations reflect seasonal abundance of phytoplankton and are highly localized. Freshwater from coastal rivers mixes with saline ocean water further contributing to habitat variability. Coastal currents tend to move organic matter along coastlines enhancing the large-scale drifting phenomenon. Tidal action also increases turbidity while facilitating the exchange of nutrients from the sea bottom into the water column. Many fish species seek out enclosed bays and estuaries, or migrate into freshwater streams to spawn. Estuaries, bays and lagoons in these regions provide abundant food supplies for numerous marine species as well as important breeding and nursery habitats. Highly productive benthic communities support an abundance of larger predators, such as tuna. Directory: downloads downloads -> Northern England’s set-jetting locations downloads -> Dynatest 3031 lwd light Weight Deflectometer downloads -> Forth coming competitive exams downloads -> Brush High School Morning Announcements Friday, September 05, 2014 all school downloads -> Year 9 The Arts — Music downloads -> Years 7 and 8 standard elaborations — Australian Curriculum: Music draft downloads -> Chris Young sets 2016 “I’m Comin’ Over” Tour headlining dates downloads -> Slavery and Abolition: the Plymouth Connection Introduction downloads -> Summer Assignment Download 2.75 Mb. Share with your friends:
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