Big changes in the Bering Sea.Global warming global warming, the gradual increase of the temperature of the earth's lower atmosphere as a result of the increase in greenhouse gases since the Industrial Revolution. is causing the Bering Sea Bering Sea, c.878,000 sq mi (2,274,020 sq km), northward extension of the Pacific Ocean between Siberia and Alaska. It is screened from the Pacific proper by the Aleutian Islands. The Bering Strait connects it with the Arctic Ocean. to heat up. Warmer waters mean that ice is melting earlier and faster than in the past. Look at the diagram below to see how a decline in sea ice is affecting life in the Bering Sea. A FROZEN WORLD Ice is vital to animals in the Bering Sea. Not only does it provide many of them with a resting place, but the ice also gives rise to a specific food chain--one that supports bottom-feeding species, like crabs and gray whales. 1) Walruses, seals, and seabirds rely on sea ice. Ribbon seals (Zool.) a North Pacific seal (Histriophoca fasciata). The adult male is dark brown, conspicuously banded and striped with yellowish white. See also: Ribbon , for instance, never go ashore: They give birth and rear their pups on the ice. Without sea ice, ribbon seals could become extinct. 2) Sea ice acts like a nursery for algae algae (ăl`jē) [plural of Lat. alga=seaweed], a large and diverse group of primarily aquatic plantlike organisms. These organisms were previously classified as a primitive subkingdom of the plant kingdom, the thallophytes (plants that (plantlike organisms that make their own food using photosynthesis). In early spring, algae bloom under the ice. 3) Since the water is so cold, only a few tiny animals like copepods are around to eat the algae. 4) The algae die and fall to the seafloor. There, they are eaten by crabs and other small creatures, which in turn feed walruses and other bottom-feeders. A THAWING SEA A sea with little ice puts animals that rely on ice for resting places at risk. It also nurtures a food chain that supports species that are different from the ones now found in the Bering Sea. Species like cod and orcas thrive in these warmer waters. 1) When seawater seawater Water that makes up the oceans and seas. Seawater is a complex mixture of 96.5% water, 2.5% salts, and small amounts of other substances. Much of the world's magnesium is recovered from seawater, as are large quantities of bromine. never freezes--or melts early--seals and walruses have fewer places to give birth. Forced into deeper waters farther north where ice remains, walruses can't dive deep enough to reach clams. 2) Without ice as a nursery, algae bloom in open waters in late spring. 3) In warmer waters, tiny animals like copepods are plentiful. They eat the algae and flourish. The tiny animals provide food for small fish like pollock and cod. Orcas feed on these fish. 4) Less food reaches the seafloor for crabs to eat. There is less food for bottom-feeding animals like walruses. it's your choice 1. The Bering Sea is located--of the Aleutian Islands Aleutian Islands (əl  `shən), chain of rugged, volcanic islands curving c.1,200 mi (1,900 km) west from the tip of the Alaska Peninsula and approaching Russia's Komandorski Islands. . A west B east C north D south 2. Which of the following are NOT affected by a decline in sea ice? A walruses B polar bears polar bear, large white bear, Ursus maritimus, formerly Thalarctos maritimus, of the coasts of arctic North America. Polar bears usually live on drifting pack ice, but sometimes wander long distances inland. C ribbon seals D cheetahs 3. A female walrus nurses her calf for roughly--years of its life. A two B four C six D eight 4. --are a polar bear s primary prey. A Adult walruses B Ringed seals ringed seal n. An Arctic seal (Phoca hispida) having white, ring-shaped markings on the sides of the body. C Gray whales D Snow crabs ANSWERS IT'S YOUR CHOICE 1. c 2. d 3. a 4. b |
|
||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion