image: Sampling the Yenisei River at Igarka. view more
Credit: Image courtesy of Arnaud Mansat (photographer).
A study finds that rivers are a significant source of mercury to the Arctic Ocean. Although elevated levels of mercury have been observed in arctic marine wildlife, few anthropogenic sources of mercury are known in the region, suggesting that mercury is transported from mid-latitudes. With a lack of data on northward mercury transport by rivers, researchers previously thought that mercury transport to the Arctic Ocean occurs via the atmospheric form of mercury. Jeroen E. Sonke and colleagues sampled outflows of the Yenisei and Severnaya Dvina rivers, which flow into the Arctic Ocean, between 2012 and 2016. The rivers experienced consistent flooding periods in spring and fall, when the amount of dissolved and particulate mercury in the rivers rose. Based on the observations, the authors extrapolated the results to include all river basins flowing into the Arctic Ocean and estimated that the rivers transport around 44 megagrams of mercury per year, an estimate in agreement with modeling simulations of the Arctic Ocean system. According to the authors, river inputs to the Arctic Ocean exceed atmospheric input. The results suggest a modified paradigm of mercury transport at high latitudes in which arctic tundra vegetation incorporates atmospheric mercury from mid-latitudes and delivers it to rivers during seasonal snow melt.
Article #18-11957: "Eurasian river spring flood observations support net Arctic Ocean mercury export to the atmosphere and Atlantic Ocean," by Jeroen E. Sonke et al.
MEDIA CONTACT: Jeroen E. Sonke, Centre National de la Recherche Scientifique, Paris, FRANCE; e-mail: <jeroen.sonke@get.omp.eu>
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