climate crisis |  Phytoplankton decline is disrupting the rest of the food chain

climate crisis | Phytoplankton decline is disrupting the rest of the food chain

(Portland) Warming waters off the east coast of the United States have killed microorganisms that form the basis of the food chain in the oceans, researchers warn.

Posted at 3:28pm


Patrick Whittle Associated Press

The increasing heat and salinity of the waters of the Gulf of Maine — which joins the Bay of Fundy along the coasts of Nova Scotia and New Brunswick — are causing a significant decline in phytoplankton production, according to Maine scientists, who recently revealed the conclusions of a multi-year study Study funded by NASA.

Phytoplankton, sometimes referred to as the “invisible forest,” are small organisms that serve as food for marine life.

The researchers found that phytoplankton in the Gulf of Maine are about 65% less productive than they were twenty years ago. The Gulf of Maine is one of the fastest warming stretches of the world’s oceans.

The loss of these small organisms could disrupt industries as important to the economy as lobster and scallops. It could also threaten already endangered species like Atlantic right whales and puffins, scientists said.

“The productivity loss over the past 20 years is profound,” said study leader, researcher William Balch of the Bigelow Laboratory for Ocean Sciences in East Boothbay, Maine. And that has important implications for what can grow there — the health of the ecosystem, the productivity of the ecosystem. »

The researchers analyzed data collected since 1998 from merchant or research vessels making the same voyages over and over again.

This data shows changes between the Gulf and the Atlantic, Balch said. Intrusion of warmer water from the North Atlantic since 2008 has created a warmer, saltier and less welcoming divide for phytoplankton, warns the study published by the Journal of Geophysical Research: Biogeosciences.

Phytoplankton are swallowed up by larger zooplankton, small fish and crustaceans, which in turn are essential to the balance of the food chain, all the way down to the sharks and whales at the top. The loss of phytoplankton “is likely to have a negative impact on the overall productivity” of larger animals and commercial fisheries, the study points out.

Cyclical sea conditions also damage phytoplankton. The El Niño weather phenomenon, which warms the surface waters of the equatorial Pacific, may slow phytoplankton production, said the National Oceanic and Atmospheric Administration, a U.S. federal agency.

The Maine researchers add that the loss of phytoplankton is worrying because the organisms, like land plants, absorb carbon dioxide from the atmosphere.

It’s part of the damage climate change is doing to ecosystems around the world, said Jeff Runge, a professor in the University of Maine’s School of Marine Sciences, who was not involved in the study.

“We have growing evidence that it’s linked to climate change,” he said. It has several implications for the system, which we’re beginning to see. »