Deposition of Biogenic Iron Minerals in a Methane Oxidizing Microbial Mat

Abstract

The syntrophic community between anaerobic methanotrophic archaea and sulfate reducing bacteria forms thick, black layers within multi-layered microbial mats in chimney-like carbonate concretions of methane seeps located in the Black Sea Crimean shelf. The microbial consortium conducts anaerobic oxidation of methane, which leads to the formation of mainly two biomineral by-products, calcium carbonates and iron sulfides, building up these chimneys. Iron sulfides are generated by the microbial reduction of oxidized sulfur compounds in the microbial mats. Here we show that sulfate reducing bacteria deposit biogenic iron sulfides extra- and intracellularly, the latter in magnetosome-like chains. These chains appear to be stable after cell lysis and tend to attach to cell debris within the microbial mat. The particles may be important nuclei for larger iron sulfide mineral aggregates.

Mineral formation during bacterial sulfate reduction in the presence of different electron donors and carbon sources

“…The formation of iron sulfides at low pH during sulfate reduction with lactate and at high pH during sulfate reduction with formate and hydrogen agrees with other studies (Donald and Southam, 1999). Greigite and elemental sulfur are among the sulfur minerals found at marine cold seeps within or near the SMTZ where their formation is thought to result from the activities of SRB (Lin et al, 2015;Wrede et al, 2013).…”

Archaeal Community Changes Associated with Cultivation of Amazon Forest Soil with Oil Palm

“…On the other hand, members of the phylum Euryarchaeota are directly involved in carbon metabolism, with several classes of methanogens and methane-oxidizing organisms [ 66 – 68 ]. Navarrete et al [ 48 ] studied the impact of converting Amazon native forest to pasture and reported changes not only to the composition and abundance of soil microbial communities but also to a decrease in the diversity of gene function.…”