CLIMATE CHANGE AT HIGH LATITUDES: AN ILLUMINATING EXAMPLE

A striking example is presented of a newly observed phenomenon in the ice-covered Arctic Ocean that appears to be a consequence of changes in the physical forcing. In summer 2011, a massive phytoplankton bloom was observed north of the Bering Strait, between Russia and the United States, underneath pack ice that was a meter thick—in conditions previously thought to be inconducive for harboring such blooms. It is demonstrated that the changing ice cover, in concert with the resulting heat exchange between the atmosphere and ocean, likely led to this paradigm shift at the base of the food chain by altering the supply of nutrients and sunlight. Such earlyseason under-ice blooms have the potential to profoundly alter the Arctic food web.