Climate change may boost toxic mercury levels in sea life | Science News


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Climate change may boost toxic mercury levels in sea life

Increased runoff shifts marine ecosystems, concentrating more of the contaminant in food webs, experiments suggest

2:10pm, January 27, 2017
researcher working with mercury

MEDDLESOME MERCURY  Increased runoff into Earth’s oceans could increase methylmercury concentrations in marine ecosystems by altering the food web, new laboratory tests show. Here a researcher adds methylmercury to a vat containing coastal microbes.

The muddying of coastal waters by climate change could drastically increase levels of neurotoxic mercury in sea life, contaminating food supplies.

Shifting rainfall patterns may send 10 to 40 percent more water filled with dissolved bits of organic debris into many coastal areas by 2100. The material can cloud the water, disrupting marine ecosystems by shifting the balance of microbes at the base of the food web, new laboratory experiments suggest. That disruption can at least double methylmercury concentrations in microscopic grazers called zooplankton, researchers report January 27 in Science Advances.

The extra mercury could reverberate up the food web to fish that humans eat, warns study coauthor Erik Björn, a biogeochemist at Umeå University in Sweden. Even small amounts of methylmercury, a form of the metal easily absorbed by humans and other animals, can cause birth defects and kidney

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