SciCheck Digest
Climate change has affected ocean ecosystems, scientists say. But an unfounded claim on social media that “plankton in the Atlantic Ocean is 90% gone” and the ocean is “now pretty much dead” is based on a faulty paper.
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The world’s oceans have changed over the last several decades. Climate change has warmed the surface water and caused the sea level to rise, for example.
But some social media accounts that post about environmental issues have made the unfounded claim, “Plankton in the Atlantic Ocean is 90% gone.”
Plankton — the catchall term for small marine plants, phytoplankton, and animals, zooplankton — serve two vital functions in the ecosystem. They are a major source of food for other marine life, and they absorb carbon dioxide while creating oxygen in the ocean.
So, if the claim were true it would, indeed, be a major environmental catastrophe. But experts who study plankton have not found that to be the case.
“We absolutely haven’t seen the drops that were noted” in the social media posts, David Johns, head of the Continuous Plankton Recorder Survey, told us in an email. “[I]n fact, in some areas there have been increases in plankton,” he said. The CPR Survey has been recording marine ecological data since 1931 and is now run by the Marine Biological Association in the U.K.
We’ll explain how the inaccurate claim about plankton developed.
It’s based on a quote from Howard Dryden, a marine biologist in Scotland who has, for most of his career, developed and distributed water treatment systems. In 2021, Dryden sought help from fellow members of the Ocean Cruising Club to gather water samples as part of a citizen science project.
He wrote in a March 11, 2021, announcement calling for volunteers, “There are around 5,000 yachts crossing oceans every year, from Arctic regions to the equator. If some of these yachts were to start collecting data, then it would be invaluable for the measurement of oceanic pollution and productivity.”
Three months later he posted a report suggesting that the primary problem facing ocean ecosystems was chemical and plastic pollution and, about a year after that, on May 6, he posted a paper titled: “Climate change…have we got it all wrong? an observational report by a Marine Biologist.”
The abstract for that paper concluded, “peer reviewed literature shows we have lost more than 50% of all life in the oceans, but from own plankton sampling activity and other observations, we consider that losses closer to 90% have occurred, and these are due to chemical pollution from, for example, wastewater and not climate change.”
The paper was cited in a July 17 article published by a Scottish newspaper, the Sunday Post, which also quoted extensively from an interview with Dryden.
Among the quotes was this, referring to plankton: “Our results confirmed a 90% reduction in primary productivity in the Atlantic. Effectively, the Atlantic Ocean is now pretty much dead.”
Shortly after the article was published, the claim that “plankton in the Atlantic Ocean is 90% gone” began circulating widely online.
Ars Technica was among the first to address the claim and, after it published a story explaining that the claim was overstated, Dryden contacted the publication and said that the Sunday Post article should have reported a “90% reduction in marine plankton in the Equatorial Atlantic, not the whole Atlantic.”
Dryden also changed the name of his May 6 paper to include the “equatorial Atlantic” distinction. It’s now titled: “Climate Change…Equatorial Atlantic Ocean plankton productivity and Caribbean pollution….a think piece for debate.”
The newspaper updated its story and included an editor’s note at the bottom explaining the changes.
The equatorial Atlantic includes currents flowing west from North Africa toward the southeast coast of the U.S. near the equator, as the name suggests.
That area doesn’t typically have high numbers of visible plankton, though.
“Equatorial waters are naturally not hotspots for plankton (unless you look at the really small stuff, like pico- and nanoplankton, which you cannot see with a typical microscope),” Johns, of the CPR Survey, told us. “So the claims are unfounded.”
Johns also noted the reference in Dryden’s paper to a global loss of 50% of plankton, and disagreed with that, too.
“I work with a large number of national and international plankton scientists,” Johns said, “and no one is reporting those sorts of declines – a decline in that order would be absolutely catastrophic, so many marine organisms depend on plankton, from larval through to adult fish, whales, whale sharks, manta rays, sea birds etc. And the phytoplankton are massively important as global producers of oxygen, and they ‘drawdown’ and fix CO2.”
The larger premise of Dryden’s paper — that climate change isn’t much of a threat — is inaccurate, too.
Looking at the anticipated impacts of climate change on the ocean alone, we can expect increased coastal flooding due to sea level rise, changes in climate patterns due to higher ocean temperatures that affect the currents, and decreased marine biodiversity as higher levels of atmospheric carbon dioxide acidify the water.
“We have seen lots of changes relating to climate change, specifically the warming of the sea surface,” Johns said, addressing Dryden’s specific claim about the amount of plankton in the equatorial Atlantic. “In many cases, this has forced some plankton groups to retract northwards into cooler waters, and has allowed warming loving species to advance northwards as conditions for them become more favourable.”
So, the claim that 90% of plankton has disappeared from the Atlantic is based on a faulty paper that was highlighted by a news outlet. Those who study the issue have found cause for concern about the impacts of climate change, but they haven’t clocked the magnitude of decline trumpeted in the viral social media claim.
Editor’s note: FactCheck.org is one of several organizations working with Facebook to debunk misinformation shared on social media. Our previous stories can be found here. Facebook has no control over our editorial content.
Sources
Intergovernmental Panel on Climate Change. Special Report on the Ocean and Cryosphere in a Changing Climate. Accessed 27 Jul 2022.
National Aeronautics and Space Administration. “How Do We Know Climate Change Is Real?” Climate.nasa.gov. Updated 26 Jul 2022.
National Oceanic and Atmospheric Administration. “What are plankton?” Updated 26 Feb 2021.
Johns, David. Continuous Plankton Recorder Survey. Email to FactCheck.org. 28 Jul 2022.
Dryden, Howard. “Climate change…have we got it all wrong? an observational report by a Marine Biologist.” 6 May 2022.
Howarth, Mark. “Our empty oceans: Scots team’s research finds Atlantic plankton all but wiped out in catastrophic loss of life.” Sunday Post. 17 Jul 2022.
U.S. Environmental Protection Agency. “Climate Change Indicators: Oceans.” Updated 12 May 2021.
United Nations. “How is climate change impacting the world’s ocean.” Accessed 29 Jul 2022.