Reading Five: Ocean Communities


Reading Five: Ocean Communities

whale.jpgImpact: Shrinking habitats for cold-water species

In the Bering Sea, we can already see rapid climate change. The temperature of the bottom water is warming substantially, forcing cold-water species northward an/or reducing their numbers. Habitat is also shrinking for ice algae and other microscopic life that live in, on, under and around sea ice.

Impact: Reduced access to food
Some species, like Arctic Cod, might like warmer waters. One important source of the cod’s diet, however, is the northern shrimp, whose numbers will likely decrease in a warmer ocean conditions.

Impact: Increased risk of oil spills
A decline in Arctic sea ice could open up new shipping routes. With more shipping, the risk of oil spills and other industrial accidents increases. Some studies suggest that the effects of oil spills in cold ocean environments last much longer than first suspected. Studies of sea otters, harlequin ducks, salmon and shellfish suggest that patches of oil left on beaches after clean-up efforts could cause chronic problems for some species for many years.

Impact: Increased exposure to harmful UV rays
Ice cover is like sun-block for the organisms living underneath it. With reduced ice cover marine plants and animals are exposed to more UV radiation. This can be harmful. For example UV radiation can reduce the productivity of phytoplankton, the tiny plants that form the base of the marine food chain, by as much as 30 %. Also UV exposure can kill fish embryos and larvae (the early life-stages of fish).

Impact: Increased acidity of ocean water
As more carbon-dioxide absorbs into ocean waters it increases the acidity of the water. This can make it difficult for animals to make shells and for coral to form.

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