Qinqin Chen , Qingru Wu, Yuying Cui, Shuxiao Wang

Global ecosystems face mercury contamination, yet long-term data is scarce, hindering understanding of ecosystem responses to atmospheric Hg input changes and policy evaluation. To address this gap, this study compiled a global mercury accumulation flux database using 221 cores from peat, lake, ice, and marine deposits. From 1700 to 2012, global averaged fluxes in peat, lake, ice, and marine deposits increased five-fold, six-fold, six-fold, and eight-fold, respectively. Notably, lake and peat mercury fluxes generally mirrored trends in total atmospheric mercury deposition modelled by GEOS-Chem and thus can reflect policy effects. For instance, the decreases of lake and peat mercury fluxes post-1950 in Europe evidenced effective environmental policies, while rises in East Asia-Oceania highlighted coal-use impacts, inter alia. Conversely, mercury fluxes in marine sediments and high-altitude natural deposits did not correspond well with atmospheric deposition, emphasising natural influences over anthropogenic impacts. Our study underscores these key regions and ecosystems for future mercury management.