Today’s Image of the Day from NASA Earth Observatory features the Gulf of Maine, where warmer and salter waters have substantially reduced the productivity of phytoplankton – the center of the marine food web.

According to a recent study from the Bigelow Laboratory for Ocean Sciences, phytoplankton are now about 65 percent less productive in the Gulf of Maine than they were two decades ago, 

“The Gulf of Maine helps fuel New England’s marine ecosystems and maritime economy,” reports ESA. “Like plants on land, phytoplankton absorb carbon dioxide from the atmosphere and use sunlight to grow via photosynthesis; they then become food for other organisms.” 

“Disruptions to the productivity of these microscopic organisms can lead to adverse effects on the region’s fisheries and the communities that depend on them.”

A 2021 study revealed that the Gulf of Maine has been warming faster than most ocean basins. The researchers at Bigelow set out to investigate how this warming may have impacted phytoplankton.

“Phytoplankton are at the base of the marine food web on which all of life in the ocean depends, so it’s incredibly significant that its productivity has decreased,” said William Balch, a Bigelow Laboratory scientist who co-led the study. “A drop of 65 percent will undoubtedly have an effect on the carbon flowing through the marine food web, through phytoplankton-eating zooplankton, and up to fish and apex predators.”

“It’s all being driven by this gigantic windmill effect happening out in the North Atlantic, which is also changing the circulation coming into the Gulf of Maine. There used to be these inflows from the North Atlantic bringing water from the southward-flowing Labrador Current, making the gulf cooler and fresher, as opposed to warmer and saltier, which is where we are now.”

Image Credit: NASA Earth Observatory

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By Chrissy Sexton, Earth.com Staff Writer