A 30 year time series shows that phytoplankton stocks near Antarctica are declining significantly. This may be causing cascading declines throughout the food web, with both Adelie penguins and krill declining.

"We're showing for the first time that there is an ongoing change on phytoplankton concentration and composition along the western shelf of the Antarctic Peninsula that is associated with a long-term climate modification," Montes-Hugo said. "These phytoplankton changes may explain in part the observed decline of some penguin populations."