Antarctic sulfate reducers - What is their favorite food?

WUNDER LEA C.; REZNIK ANASTASIIA; BARKOWSKY JANINA; LAUFER-MEISER KATJA; AROMOKEYE DAVID A.; WILLIS PORATTI GRACIANA; FRIEDRICH MICHAEL

Antwerpen

Simposio; International Symposium on Microbial Sulfur Metabolism; 2023

University of Antwerp

Sulfate reduction is a wide spread electron accepting process in marine sediments with considerable contribution to organic matter degradation. Furthermore, multiple autotrophic sulfate reducing bacteria are known and sulfate reduction can also be coupled to hydrogen oxidation. In Arctic surface sediments, it has been shown that acetate and other organic compounds act as electron donors, but also that there must be another, so far unidentified, electron donor for this process. However, in Antarctic sediments we were so far unable to show acetate as suitable sole electron donor and carbon source for sulfate reducers. Here, we test organic versus inorganic electron donors and carbon sources for sulfate-reducing microorganisms using ferruginous surface sediment from Potter Cove (King George Island/Isla 25 de Mayo, Antarctica). In slurry incubations, sulfate reduction rates and active microorganisms are compared when providing, alone or in combination, acetate or bicarbonate and hydrogen as carbon source and electron donor. The active bacterial community is identified by RNA stable isotope probing. This experiment aims to identify the heterotrophic and autotrophic sulfate reducing bacteria in Antarctic sediments and quantify the importance of different electron donors for sulfate reduction.