Environmental Controls of iron-reducing microorganisms in Antarctic marine sediments (ECIMAS): 2021 Update

WUNDER LEA C.; AROMOKEYE DAVID A.; WILLIS PORATTI GRACIANA; OTERSEN CAROLIN; HENKEL SUSANN; FRIEDRICH MICHAEL

Workshop; Coordination Workshop SPP 1158; 2021

DFG

Rapid warming has affected the Western Antarctic Peninsula (WAP) strongly over the last 50 years resulting in glacier retreat at unprecedented rates [1]. Consequently, increasing amounts of iron (III) oxides [2,3] accumulate in areas close to the retreating glaciers. Microbial iron reduction of insoluble iron (III) oxides linked to organic matter oxidation can produce dissolved iron in pore water, contributing to benthic Fe2+ fluxes [2] and potentially to the export of iron compounds to the Southern Ocean, known for being limited in primary productivity [4]. However, little is known about geochemical cycling, organic matter degradation and metal/sulfate reduction in Antarctic sediments. The aim of our work is to elucidate the eco-physiology of iron-reducing microbial communities, and their environmental controls in Antarctic marine sediments. Our study site includes the shallow sediments at Potter Cove, a hot spot of environmental change at King George Island (KGI, Isla 25 de Mayo) in the northern tip of the WAP [4], including sites that have been newly exposed due of receding glaciers, accumulating iron oxides and high dissolved iron concentrations compared to typical sulfidogenic sites as a reference, indicative of sulfate reduction.