Marine phytoplankton and sea-ice initiated convection drive spatiotemporal differences in Arctic summertime mercury rebound
2025
Yue, Fange | Angot, Hélène | Liu, Hongwei | Xie, Zhouqing | University of Science and Technology of China [Hefei] (USTC) | Institut des Géosciences de l’Environnement (IGE) ; Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Observatoire des Sciences de l'Univers de Grenoble (Fédération OSUG)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP) ; Université Grenoble Alpes (UGA)
International audience
显示更多 [+] 显示较少 [-]英语. Gaseous elemental mercury (GEM) concentrations in the Arctic exhibit a distinct rebound during the summer months, with notable spatiotemporal variations observed in this phenomenon; however, the underlying mechanisms remain poorly understood. On the basis of targeted cruise observations from the Bering Strait to the North Pole, this study captured the summertime GEM rebound in the Pacific sector of the Arctic Ocean. Moreover, we identified synchronous increases in dissolved gaseous mercury (DGM) concentrations during the GEM rebound in the Marginal Ice Zone (MIZ). Combined with Generalized Additive Model (GAM) simulations, we confirm that oceanic mercury emissions from the MIZ contribute to this phenomenon. We also show that the spatiotemporal variability of dissolved organic components associated with phytoplankton, along with local atmospheric convection triggered by sea-ice melting in the MIZ, plays a crucial role in the observed spatiotemporal differences in the GEM rebound. In the context of rapid Arctic warming, with expected increases in primary productivity and more frequent local convection, the air-sea exchange of mercury is likely to intensify, amplifying the summertime "mercury source" effect in the Arctic Ocean.
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