Circumpolar rivers deliver large quantities of mercury to the Arctic Ocean during summer, according to a study published online this week in Nature Geoscience. The researchers suggest mercury loads in the Arctic Ocean could prove highly sensitive to climate-induced changes in river flow and permafrost thaw.
Mercury concentrations in the Arctic Ocean peak during summer months, posing a health concern to indigenous peoples, who rely heavily on marine-based diets. Jenny Fisher and colleagues used a global model to pinpoint the summertime source of mercury in the Arctic Ocean. According to their simulations, circumpolar rivers supply large quantities of mercury to the Arctic Ocean during summer, and constitute the dominant mercury source on an annual basis.