[CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0/)]

This article was originally published on PEW

“Antarctic krill, the thumb-sized crustaceans that form the foundation of the Southern Ocean food web, are facing increasing pressure from climate change, underscoring the need to protect this keystone species and its habitat.

A study analyzing 90 years of data, published Jan. 21 in the journal Nature Climate Change, found that the center of the krill population near the Antarctic Peninsula has shifted about 440 kilometers (nearly 275 miles) southward, and that the number of juveniles has dropped since 1970. This news has huge implications: As warming waters and sea ice loss force krill to retreat toward the continent—where the landmass blocks further southward movement—their available habitat decreases, which might lead to further drops in their numbers, and cascading impacts on the entire Southern Ocean food web.

The Antarctic Peninsula is one of the fastest-warming regions in the world, and changes in the krill population—and the broader food web—are a direct result of rising ocean temperatures and reduced sea ice. Krill are the primary food source for many species in the Southern Ocean, including penguins, seals, and whales. The reduction in the numbers and overall health of krill could lead to similar negative effects among species that rely on the lynchpin crustacean…”

Read on at: PEW.