The Atlantic Ocean has not lost 90% of its plankton

Social media claims that the Atlantic’s plankton population has suffered a decimating drop of 90 percent, citing research from marine biologists. But the claim is false; the paper — which the author described as an “observational think piece” that was never “intended to be peer-reviewed” — covers only one part of the ocean, and independent researchers say there is no evidence that plankton activity has declined by such a large margin.

“Scientists reveal our empty seas. Research: 90% of Atlantic plankton lost,” reads the headline of a front-page article from The Sunday Post, a Scottish newspaper, published on July 17, 2022.

The same claim then garnered thousands of likes and shares on social media after the Netflix documentary Seaspiracy and the Save the Reef charity project shared it.

Screenshot of the 17 July 2022 front page of The Sunday Post

Screenshot of an Instagram post taken on July 26, 2022

According to the National Oceanic and Atmospheric Administration (NOAA), plankton can be categorized into two main groups: “phytoplankton (plants) and zooplankton (animals).” They play a crucial role in the ocean’s ecosystems.

Climate change has had an effect on the habitat of plankton. But the claims shared online are false.

Scientists say that 90% of plankton have not disappeared from the Atlantic Ocean – and that if they had, it would have caused significant and visible disruption to marine life.

Researcher changes claims

The Sunday Post article is based on a project by Howard Dryden and Caroline Duncan, marine biologists at the Global Oceanic Environmental Survey (GOES) Foundation.

Their piece, titled “Climate change … plankton productivity in the equatorial Atlantic and Caribbean pollution … a think piece for debate,” draws on “plankton sampling activity and other observations” to conclude that plankton losses “close to 90% have occurred.”

But Dryden said the project never covered the entire Atlantic Ocean, as the posts and The Sunday Post article claim.

“Mistakes have been made in the reporting of our results, we may have been inadvertently responsible by not communicating properly, but I want to make a statement that the results only apply to the equatorial Atlantic region,” he said in a statement sent to AFP.

Dryden added that the report, which underwent revisions, is an “observational think piece” — not a peer-reviewed scientific study.

“This is only an initial observation and comment on the results obtained, there was no intention to have the document peer-reviewed,” he said.

The marine biologist told AFP that the statement of a 90% reduction in plankton productivity in the region was a “prediction” based on other data and reports.

The headline for the online version of The Sunday Post’s story has been updated and a note added to the bottom of the piece.

“This story was edited on July 23, 2022 to clarify that the samples studied by the Global Oceanic Environmental Survey Foundation were taken from the equatorial Atlantic Ocean and have not yet been confirmed by other scientists or research teams,” the note said.

Jim Wilson, editor of The Sunday Post, told AFP in an email that the newspaper “declines to misrepresent the research and stands by its reporting”.

“We accurately reported Dr. Dryden’s research,” he said. “Our headline might have been more specific about the geographic limits of that research, but the story was clear and would have left no fair reader confused.”

Scientists question findings

But several independent researchers urged caution after reviewing Dryden and Duncan’s piece, pointing to an absence of a transparent methodology used to collect and analyze data.

“We cannot trust the findings presented in this report,” Marie-Fanny Racault, a biological oceanographer who studies climate impacts on marine ecosystem resources, told AFP.

Racault, lead author of a chapter on marine and coastal ecosystems for the latest Intergovernmental Panel on Climate Change (IPCC) reports, said the claim that 90% of plankton is gone from the Atlantic Ocean is “not supported by robust scientific evidence.”

“No baseline reference is given, ‘90% gone’ but since when? Or compared to what period or condition?” she said. “Furthermore, the report fails to account for previous findings reported in published peer-reviewed scientific literature.”

Marine conservation ecologist Abigail McQuatters-Gollop, who chairs plankton expert groups for the Convention for the Protection of the Marine Environment of the Northeast Atlantic (OSPAR), echoed Racault’s concerns.

“It is very difficult to identify real changes in oceanic variables (as opposed to natural variability) without at least 20 years of data,” she told AFP, adding that “plankton identification is a difficult skill.”

Environmental damage in the sea caused by human activity (AFP / Emmanuelle MICHEL, Emilie BICKERTON)

McQuatters-Gollop’s team works with hundreds of thousands of plankton samples, collected over 80 years from 14 different countries.

“This compares with the 500 samples used in the paper whose collection and analysis methodology is not described,” she said.

The scientist told AFP that “if some aspect of plankton had changed by 90% recently,” the consequences would be felt in many areas, such as fisheries.

“A catastrophic change in productivity such as that described by Dryden would be much more obvious than what is currently observed, with likely a collapse or near-collapse of the Atlantic marine food web,” McQuatters-Gollop said.

However, the fact that the claims shared online are inaccurate does not mean that climate change is not a threat to plankton.

The latest IPCC assessment report indicates ocean warming and changes in sea ice are among the most important drivers affecting plankton productivity.

“There is no doubt that ongoing and future climate change and ocean acidification are altering the marine environment,” said Alessandro Tagliabue, a marine biogeochemist at the University of Liverpool. “Understanding how these changes will affect plankton productivity is one of the great challenges facing the oceanographic and marine science communities.”

AFP has fact-checked other claims about the environment here.

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