Climate Change Could Put Tiny Krill at Big Risk

They may be small, but krill — tiny, shrimp-like creatures — play a big role in the Antarctic food chain.  As climate change warms the Southern Ocean and alters sea ice patterns, though, the area of Antarctic water suitable for krill to hatch and grow could drop precipitously, a new study finds.

Most Antarctic krill are found in an area from the Weddell Sea to the waters around the Antarctic Peninsula, the finger of land that juts up toward South America.  They serve as an important source of food for various species of whales, seals and penguins.  While those animals find other food sources during lean years, it is unclear if those alternate sources are sustainable long-term.

Antarctic krill, centimeter-long shrimp-like crustaceans that feed primarily on phytoplankton, are a key part of the Antarctic marine food chain.

Over the past 40 years, populations of adult Antarctic krill have declined by 70 to 80 percent in those areas, though researchers debate whether that drop is due to the effects of climate change, a rebound in whale populations after the end of commercial whaling or some combination of those pressures.

Because of its key role in the regional food chain, scientists are concerned about the impacts that future climate change may have on the krill population and the larger Antarctic ecosystem.

In the new study published in the journal Geophysical Research Letters, Andrea Piñones and Alexey Fedorov examined how expected changes in ocean temperatures and sea ice coverage might affect krill during their earliest life stages when they are most vulnerable to environmental conditions.

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