High Mercury Accumulation in Deep-Ocean Hadal Sediments
Climate Change Resilience
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Ocean sediments are the largest sink for mercury (Hg) sequestration and hence an important part of the global Hg cycle1. Yet accepted global average Hg flux data for deep-ocean sediments (> 200 m depth) are not based on measurements on sediments but are inferred from sinking particulates2. Mercury fluxes have never been reported from the deepest zone, the hadal (> 6 km depth). Here we report the first measurements of Hg fluxes from two hadal trenches (Atacama and Kermadec) and adjacent abyssal areas (2–6 km). Mercury concentrations of up to 400 ng.