Rising ocean surface temperatures caused by climate change could make fish accumulate more mercury, increasing the health risk to people who eat seafood, U.S. researchers said Thursday.

Mercury released into the air through industrial pollution can accumulate in streams and oceans and is turned into methylmercury in the water, but until now, little has been known about how global warming may affect mercury bioaccumulation in marine life, and no study has specifically demonstrated the effects using fish in both laboratory and field experiments.

Researchers from the Dartmouth College and other U.S. institutions studied killifish under varying temperatures in the lab and in salt marsh pools in Wells located along the southern Gulf of Maine coastline.

Fish in the marshes ate insects, worms and other natural food sources, while the lab fish were fed mercury-enriched food, they reported in the journal PLOS ONE.

The study showed the fish in warmer waters ate more but grew less and had higher methylmercury levels in their tissues, suggesting increases in their metabolic rate caused the increased uptake of the toxic metal.

"This increase can be propagated to higher trophic level fish consumed by humans, resulting in increased human exposure to MeHg (methylmercury)," the researchers wrote.

"This effect should be incorporated into policy and management efforts aimed at reducing human health risks from MeHg exposure," they added.