Filling the Gap of Mercury Isotopic Composition in the Ocean

抄録

As one of the most important reservoirs of mercury (Hg) on earth, ocean plays a crucial role in mediating the global cycling of Hg. Mercury undergoes complex migration and transformation processes between multiple interfaces of the ocean. Recently, Hg stable isotope approach has shown great advantages in studying the biogeochemical cycling of oceanic Hg, from tracing sources and processes to reconstructing paleoenvironment and paleoclimate. Here, we overviewed the accurate analytical methods for measuring Hg isotopes in different marine samples, summarized the reported Hg isotope dataset in seawater, sediment/particulate, and biological samples, and comprehensively analyzed the fractionation mechanisms of Hg isotopes and their potential applications in tracing marine Hg cycling. We found that 1) Hg isotope data in seawater and marine particles are very limited, 2) marine Hg isotope fractionation mechanisms, especially mass-independent fractionation mechanisms remain unclear, (3) studies on Hg transfer in marine food chain and Hg exchange amongst reservoirs are constricted only by limited Hg isotope data in single Hg species, thus with great uncertainity, and (4) reconstruction of