Scientists say loss of tiny organisms is wreaking havoc on ocean and fisheries

PORTLAND, Maine (AP) – Warming waters off the East Coast has had an unseen but very high cost: the loss of microscopic organisms that form the basis of the ocean’s food chain.

The rising temperature and salinity of the Gulf of Maine, off New England, is causing a dramatic drop in phytoplankton production, according to Maine-based scientists who recently reported the results of a year-long NASA-funded study. Sometimes described as the “invisible forest,” phytoplankton are small plant-like organisms that serve as food for marine life.

Scientists have found that in the Gulf of Maine, part of the Atlantic Ocean bordered by New England and Canada, phytoplankton are about 65% less productive than they were two decades ago. The Gulf of Maine has emerged as one of the fastest warming parts of the world’s oceans.

The potential loss of phytoplankton has emerged as a serious concern elsewhere in recent years, such as the Bering Sea off Alaska. The loss of tiny organisms has the ability to disrupt valuable fishing industries for species such as lobster and scallops, and could further endanger endangered animals such as North Atlantic true whales and Atlantic gulls, the scientists said.

“The drop in productivity over these 20 years is huge,” said William Balch, Senior Research Scientist for Ocean Sciences at the Bigelow Laboratory in East Boothbay, Maine, who led the study. “And that has big implications for what can grow here. The health of the ecosystem, the productivity of the ecosystem.”

The scientists did the study using data collected by monitoring chemical changes in the Gulf of Maine since 1998. The samples used to carry out the study were collected via commercial ferries and research vessels operating repeatedly on the same routes.

Balch said the data show changes between the gulf and the wider Atlantic. Warm water intrusions from the North Atlantic since 2008 have created a warmer, saltier and less hospitable bay for phytoplankton, according to the study. The scientists published their findings last June in the Journal of Geophysical Research: Biogeosciences.

Phytoplankton is eaten by larger zooplankton, small fish and crustaceans and is critical to sustaining larger marine life in the food chain such as sharks and whales. The study notes that phytoplankton loss “will likely have adverse effects on the overall productivity” of larger animals and commercial fisheries.

Declining fish stocks in the Gulf of Maine will be particularly troubling to American fishermen, as it is an important backdrop for the US lobster industry. Other important species such as haddock, flounder and pollock are also harvested here.

Researchers have followed similar warming trends in the Bering Sea, Southern Ocean and northern Barents Sea in recent years. The effect of warming on plankton is a subject of ongoing scientific research. A 2020 article in the journal Nature Communications revealed that climate change is “predicted to trigger major changes in the geographic distribution of marine plankton species.”

Cyclic ocean conditions have also put more pressure on phytoplankton. The National Oceanic and Atmospheric Administration said the El Niño climate model could reduce phytoplankton production as surface water in the equatorial Pacific warms. NOAA said the effects were a lack of anchovies off South America, less squid off California, and less salmon in the Pacific.

Maine scientists say the loss of phytoplankton is also important because the organisms absorb carbon dioxide from the atmosphere just as plants do on land.

Jeff Runge, a professor in the University of Maine School of Marine Sciences, who was not involved in the study, said climate change is part of how it is taking over ecosystems around the world.

“There is growing evidence that it is linked to climate change,” said Runge. “It has all kinds of effects that we’re starting to see on the system.”

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Follow Patrick Whittle on Twitter: @pxwhittle

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