Fig. 7: Diagram of the main processes that drive the significant Hg(0) or gaseous elemental mercury(GEM) (re)-emission in the Marginal Ice Zone (MIZ). | Nature Communications

Fig. 7: Diagram of the main processes that drive the significant Hg(0) or gaseous elemental mercury(GEM) (re)-emission in the Marginal Ice Zone (MIZ).

From: The Marginal Ice Zone as a dominant source region of atmospheric mercury during central Arctic summertime

Fig. 7

The main processes including (1) previously deposited Hg(II) during springtime atmospheric Hg depletion events (AMDEs) is transferred to the surface ocean with melting ice/snow-water, resulting in a large Hg load in surface seawater in the MIZ; (2) high phytoplankton mass in the MIZ may lead to a high reduction capacity for Hg(II) in the MIZ, as the excretion of photoreactive organic compounds by phytoplankton can facilitate the photoreduction of Hg(II) to Hg(0) via electron transfer. In addition, phytoplankton can also directly contribute to the reduction of Hg(II) to Hg(0) through an enzymatic detoxification mechanism linked to their photosynthetic activity; and (3) the melting of sea-ice and the absence of upper ocean stratification in the MIZ (i.e., absence of a meltwater layer) facilitates air–sea gas exchange. The figure was generated using Adobe Photoshop 2021 software (version22.5).

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