Increased amounts of carbon dioxide are seeping into the ocean, acidifying the ocean, and soaking into the gills of various reef fish. These fish then experience behavioral abnormalities, like hyperactivity, altered vision, and attraction to the scent of their own predators. These findings from 2009 point to a potential mass endangerment of various reef ecosystems directly caused by global warming. 11 years later, researchers are disputing whether these findings are even accurate.
A 3-year effort by biologists from around the globe resulted in finding the results from the 2009 set of studies irreplaceable. The effort was published in an article in this week’s Nature magazine.
“Our findings indicate that the reported effects of ocean acidification on the behavior of coral reef fishes are not reproducible,” said Timothy Clark, a co-author of the Nature paper. “Behavioral perturbations will not be a major consequence for coral reef fishes in high CO2 oceans.”
Recent decrease in pH within the world’s oceans have mainly been attributed to human impact like increased fossil fuel use according to the National Ocean Service. Burning fossil fuels increases the amount of carbon dioxide in the atmosphere which is then absorbed into the ocean. Marine biologists have been closely monitoring the effects of ocean acidification on sea life with several studies already proving the slow dissolution of crustaceans. Not as much has been proven about direct effect on fish species.
Clark’s research group found that reef fish exposed to decreased pH levels had negligible effects on hyperactivity, vision, and attraction to predators; directly contradicting the findings of the original group of studies.
The original findings detailed small sample sizes in their methods, testing roughly ten individuals of each reef species. These small sample sizes made it difficult to produce replicable results for Clark and his group of researchers.
Philip Munday, a co-author of many of these fish behavioral studies being challenged, continues to stand by his original work. He said there were methodological differences between his study and the replication studies.
“Replication of results in science is critically important, but this means doing things in the same way, not in vastly different ways,” Munday said.
Despite the groundbreaking study being challenged, the research isn’t necessarily being discounted according to biologist Shinichi Nakagawa who did not partake in either the replication study or the original. Replication studies rather serve a purpose to improve pre-existing science.
“This will instigate and inspire more replication studies—not to prove previous results wrong but to make our science more robust and trustworthy,” Nakagawa said.
Sources:
https://www.sciencedirect.com/science/article/pii/S0048969720301200#!
https://oceanservice.noaa.gov/facts/acidification.html
Click to access 8c3378fb44c560bb2ba0607d528ef8632b47.pdf
https://www.nature.com/articles/s41586-019-1903-y
https://www.nature.com/articles/nclimate2195
https://www.sciencedaily.com/releases/2020/01/200108131642.htm
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