Climate change could increase mercury levels in fish

| October 10, 2013

killifishResearchers from Dartmouth College in the USA have discovered that higher sea temperatures may have an effect on the bioaccumulation of toxic methyl mercury in marine fish.

The team studied estuarine killifish (Fundulus heteroclitus) both in natural salt pools in coastal marsh and in the laboratory to investigate the effect of varying temperature regimes on the methyl mercury concentrations in the fish. The field experiments used natural temperature gradients in the pools and allowed the fish to feed on natural food sources, while the laboratory experiments used a wider range of temperatures and exposed the fish to methyl mercury-enriched food.

Methyl mercury concentrations were found to rise significantly at elevated temperatures in both sets of experiments, but other variables in the field experiments (salinity and methyl mercury levels in sediment) did not seem to affect bioaccumulation. The fish kept at warmer temperatures ate more food, but grew more slowly. The authors of the study concluded that increased metabolic rate in the fish was the cause of the higher levels of methyl mercury and they suggest that predicted warmer sea temperatures could increase human exposure to methyl mercury through fish.

The study is published in the journal PLOS ONE and can be found in full here.

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Category: Research

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