Key Phytoplankton Species Counts Down 20% In 80 Years; Rate Of Warming 10-30X Faster Than Last Ocean Warming Period [View all]

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To assess future impacts of warming waters on plankton, Schmidt and her colleagues turned to ancient changes. The team analyzed an extensive fossil record of a type of plankton called foraminifera, which leave behind tiny shells that fall to the seafloor when they die. While many plankton acclimated to the increase in temperature from the height of the last ice age 20,000 years ago to today, plankton will decline in biomass by more than 10 percent if the world warms by 3 degrees Celsius above preindustrial levels by the end of the century, researchers found.

It’s a rate of warming that researchers say the plankton simply cannot withstand. “The last deglaciation took several thousand years,” Schmidt said. “The same degree of warming is now happening over 100 years.”

The decline in plankton is already underway. In the second study in Nature, plankton ecologist Sonia Chaabane and her colleagues combed through eight decades’ worth of data on plankton collected with nets, traps and other instruments around the world. Scrutinizing nearly 200,000 samples, the team found the abundance of foraminifera has already dropped by nearly a quarter since the 1940s, with many species migrating away from the equator and deeper in the water column to survive.

“We are not sure that the migration would be enough for them,” Chaabane said. “The change is very, very huge, very fast — and it will continue being fast, we think,” she added. Michal Kucera, a micropaleontologist at the University of Bremen who was not involved in the two papers, noted there are lots of challenges to understanding plankton. Foraminifera, for instance, are only one type of plankton, and the researchers’ methods for collecting them have changed over time. Still, he said the results should be taken seriously. “No matter where and how we look, the plankton of today is already not what it used to be,” he said.

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https://www.washingtonpost.com/climate-environment/2024/11/13/plankton-food-study/