Warming ocean could increase levels of mercury found in fish

A warming ocean caused by climate change could make fish accumulate more mercury, increasing the health risk to people who eat seafood, U.S. researchers say. Scientists at Dartmouth College with research colleagues have reported the results of a marine study in the journal PLoS ONE. Until now, they said, little has been known about how global warming might affect mercury bioaccumulation in marine life. No previous study has demonstrated the effects using fish in both laboratory and field experiments, they said, so a study was initiated with killifish under varying temperatures in both a lab and in salt marsh pools in Maine. Results showed fish in warmer waters ate more but grew less and had higher methylmercury levels in their tissues, the researchers reported, suggesting increases in their metabolic rate in warmer temperatures caused an increased uptake of the toxic metal. Mercury in the atmosphere from industrial pollution can accumulate in streams and oceans and is turned into methylmercury in the water.