By Heather Chinn
A study suggesting fish are at risk from microplastic marine pollution has been withdrawn after it was discredited by an official inquiry.
In 2016 a paper in the prestigious journal Science made headlines across the world by claiming young European perch in the Baltic Sea preferred to eat 0.09mm polystyrene beads of the type found in cosmetic scrubs, rather than their natural food, a tiny brine shrimp.
The study, by two scientists from Sweden’s Uppsala University, reported the unnatural diet restricted the fish larvae’s growth and appeared to leave them more vulnerable to predators, providing a possible explanation for falling numbers of young perch in the Baltic.
Although other research had highlighted the potential risk to fish from microplastic marine pollution the study was seen as pioneering because it examined the effects of the microplastics at levels similar to those found at sea.
But questions about the the paper were raised when fellow marine scientists questioned whether a study on the scale of the project described by the authors could have been carried out in the time claimed for it.
Science has now published a statement retracting the original paper in full on the recommendation of an official inquiry which said the authors, Uppsala University research fellow Oona Lonnstedt and her supervisor Peter Eklov, had been “guilty of scientific dishonesty”.
The report, issued in April by Sweden’s Central Ethical Review Board (CEPN), also described the pair’s answers to its investigation as having “been in all essentials deficient, at times contradictory and have not infrequently given rise to further questions.”
Science, which published an editorial expressing disquiet over the study last December, today stated, “The weight of evidence is that the paper should now be retracted,” and added the paper’s authors had also last month requested that it be withdrawn.
The CEPN inquiry heard the study was based on experiments carried out by Dr Lonnstedt at Ar research station on the Swedish island of Gotland in 2015.
But when the paper appeared in Science marine scientists who had been at Ar at the same time as Lonnstedt immediately challenged it.
The allegations led to an inquiry by Uppsala University which dismissed the claims but the row rumbled on, and a second inquiry was held by CEPN which appointed a fish scientist from Stockholm University to investigate.
The CEPN report, published last month, said Dr Lonnstedt and Dr Eklov had failed to post the data supporting their paper on Science’s website or another publicly accessible site, as required by the journal. Dr Lonnstedt said it had been stored on a laptop stolen from an unlocked car shortly after publication of the paper, and other data had been lost when a university computer server broke down.
The CEPN report also found the pair claimed in the research paper to have obtained an ethical permit for the study. Later they told Uppsala University the permit arrived two weeks after the study began. But CEPN found the permit was granted over a month after the experiments ended and for a different type of study at a different research station.
The pair’s failure to post the data and false statements about the ethical permit made them “guilty of scientific dishonesty” the CEPN report concluded.
A separate inquiry is still being conducted by Uppsala University.