Incubation Experiments, Observations, and Modeling Highlight the Key Role of Dimethylmercury on Seawater Methylmercury Distributions.

The origin of the bioaccumulative neurotoxin methylmercury (MeHg) in the ocean remains elusive. The current paradigm suggests that the microbial methylation of inorganic Hg within the oceanic water column produces monomethylmercury (MMHg) and potentially dimethylmercury (DMHg). Reaction rates and main drivers governing MeHg levels (sum of MMHg and DMHg) are poorly constrained.

Natural Iron Fertilization Moderates Hydrothermal Mercury Inputs from Arc Volcanoes.

Methylmercury is a bioaccumulative neurotoxin that poses severe risks to marine ecosystems and human health worldwide. Hydrothermal systems and submarine volcanoes are natural sources of mercury, yet the magnitude of emissions, their transport, and their impact on marine ecosystems remain poorly understood. Quantifying natural mercury fluxes is essential to understanding anthropogenic perturbations and guiding effective reduction strategies.

Mercury dynamics in the mangrove-influenced estuary of the Parnaíba Delta, Brazil.

The Parnaíba River Delta (PRD), located in northeastern Brazil, is an ecologically crucial estuarine system little impacted by anthropogenic activities. This study aimed to assess mercury (Hg) contamination levels in the water and sediments and their link to changes in the hydrographic parameters across the delta to evaluate spatial distribution patterns and Hg speciation. Water and surface sediment samples were collected from 12 stations throughout the PRD.