A new talk in the Geomicrobiology Network Webinar Series
17th April, 2.00 pm BST
Dr. Isabel Sanz-Sáez
Dept. of Chemistry, Umeå University, Sweden
Register here. There is no charge.
Widespread Microbial Mercury Detoxification in the Global Dark Ocean Revealed by Integrated Meta-Omics and Cultivation
The ocean’s mercury (Hg) content has tripled due to human activities, yet methylmercury (MeHg) concentrations in the deep ocean remain low and difficult to measure, limiting our understanding of microbial Hg cycling. To address this, we combined culture-independent meta-omics analyses with culture-dependent microbial isolation to investigate Hg-transforming bacteria across global oceans.
Analysis of 52 bathypelagic metagenomes and 26 metatranscriptomes revealed widespread presence and expression of merA and merB, genes responsible for Hg(II) reduction and MeHg demethylation, particularly in particle-attached communities. Complementary studies of 290 marine isolates, including Alteromonas and Marinobacter species, showed variable Hg tolerance, with Alteromonas sp. ISS312 degrading 98% of MeHg in 24 hours and its genome prevalent in deep-ocean metagenomes. This integrated approach demonstrates that methylmercury demethylation and Hg(II) reduction are widespread microbial processes in the global dark ocean, and highlights how combining culture-dependent and independent methods can advance our understanding of microbial contributions to the oceanic Hg cycle.
The results of this studies highlighted the importance to be able to detect merA and merB genes in different ecosystems in order to further understand the Hg cycle. Given the difficulty in reliably identifying merA and merB genes, through a collaborative effort we are now building a curated merAB database to improve detection across ecosystems.
Register here. There is no charge.