Mercury: biogeochemistry and impact in the the global ocean

As recent as 2013, over 130 countries signed the Minamata Convention, a global treaty to protect human health and the environment from the adverse effects of mercury. Despite the strong global concern on mercury, in particular its organic chemical form monomethylmercury (MeHg), which is one of the top ten chemicals of public health concern, little is known about the fundamental mechanistic understanding of MeHg degradation in the environment. Key biological processes govern the formation and degradation of MeHg. While it is known for long time that biological MeHg degradation is mediated by the mer operon, the gene cluster hgc, involved in microbial MeHg formation, was recently unveiled. The recent discovery of the hgc opened a new, rapidly expanding, research direction in mercury biogeochemistry science which has dramatically advanced our understanding of the taxonomic identity and complexity of microbial communities involved in MeHg. However, it still remains uncertain if rates of MeHg formation are constrained by the molecular-level methylation/demethylation processes mediated by the hgc genes. Furthermore, attempts to parameterize accurate predictive models for MeHg formation rate or concentration in the environment have so far not been successful. This significantly restrains our fundamental understanding of Hg’s biogeochemical cycle and ability to predict MeHg exposure to wildlife or humans. In my talk I will talk about the current state of the art of the biogeochemical processes governing MeHg formation and degradation processes in aquatic systems. In particular, I will show how combining metagenomic and metatranscriptomic data (Figure 1) with a detailed characterization of mercury chemical speciation but also with marine isolates provides a refined understanding of limiting factors for MeHg formation and thus enable refined predictions of MeHg levels in the Sea

Bibliographic Details

Main Author:	Bravo, Andrea G.
Format:	material didáctico biblioteca
Language:	English
Published:	CSIC - Instituto de Ciencias del Mar (ICM) 2021-10-15
Online Access:	http://hdl.handle.net/10261/252873
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