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Marine plankton hold a long record of ocean health

By using samples from an almost century-old, ongoing survey of marine plankton, a team of researchers led by the University of California, San Diego has found that increasing levels of manmade chemicals found in some parts of the world’s oceans might play an important role in monitoring the impact of human activity on ecosystem health, and may be used in the future to examine the connections between ocean pollution and land-based rates of childhood and adult chronic diseases.

“This was a pilot study to test the feasibility of using archived samples of plankton from the Continuous Plankton Recorder (CPR) Survey to reconstruct historical trends in marine pollution over space and time,” said senior author Robert K. Naviaux, an expert in Mitochondrial Medicine and Complex Chronic Disorders at UC San Diego. “We were motivated to explore these new methods by the alarming increase in childhood and adult chronic disease that has occurred around the world since the 1980s.”

“Recent studies have underscored the tight linkage between ocean pollution and human health. In this study, we asked the question: Do changes in the plankton exposome (the measure of all exposures in a lifetime) correlate with ecosystem and fisheries health? We also wanted to lay the groundwork for asking a second question: Can humanmade chemicals in plankton be used as a barometer to measure changes in the global chemosphere that might contribute to childhood and adult illness?”

The scientists collected plankton specimens from three different locations in the North Pacific between 2002 and 2020, and assessed their exposure to a variety of humanmade chemicals, including pharmaceutic products, persistent organic pollutants (POPs) such as industrial chemicals, phthalates and plasticizers (substances derived from plastics), pesticides, and personal care products.

The analysis revealed that, although many of these products have decreased in amount during the past two decades, nearshore areas closest to human activities and subject to terrestrial runoff or aquaculture still had high level of various chemicals that impacted plankton. Moreover, perfluoroalkyl substances – a type of chemicals commonly used to enhance water-resistance in various everyday products (such as packaging, clothing, or cookware), which seem to impact human health by inhibiting mitochondrial proteins – were prominent in the plankton exposome, as were phthalates, which are known to disrupt endocrine functions.

“Plankton are responding to the chemicals in their exposome, in part by changes in their own mitochondria that change their biology, and so too, I would argue, are humans. It is my hope that the use of our methods by research groups around the world will reinforce the connection between ecosystem health and human health, and provide new tools to monitor how the human chemical footprint has changed over the past century. Follow-up studies by epidemiologists and marine ecologists are needed to test if and how the plankton exposome correlates with important medical trends in nearby human populations like infant mortality, autism, asthma, diabetes, and dementia,” Naviaux concluded.

The study is published in the journal Science of the Total Environment.

By Andrei Ionescu, Staff Writer

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