Rapid Melting in Arctic Causing Major Changes in N. Atlantic

The melting of sea ice and glaciers in the Arctic is leading to major changes in the North Atlantic, including freshening and cooling of ocean water and shifts in populations of phytoplankton, zooplankton, and fish, according to a new study. Cornell University oceanographer Charles Greene, lead author of the study in the journal, Ecology, said that a warming trend “unprecedented in human history” had enabled microscopic algae from the Pacific Ocean to migrate through the Arctic to the North Atlantic for the first time in 800,000 years. In addition, melting glaciers, increased runoff from Arctic rivers, and swiftly melting Arctic sea ice — which is mainly freshwater — were altering ocean currents and leading to fresher and colder North Atlantic waters. As a result, populations of some phytoplankton, crabs, and shrimp were increasing, while other sea life, including cod, may be on the decline. Greene warned that this “freshwater forcing” could, by next century, shut down the vast ocean conveyor belts that circulate cold water throughout the globe, potentially leading to abrupt climate change.