Macroalgae degradation promotes microbial iron reduction via electron shuttling in coastal Antarctic sediments

• DOI: 10.1016/j.envint.2021.106602
• Publication Date: 2021-05-26T03:09:45Z
• Authors: David A. Aromokeye; Graciana Willis-P...; Lea C. Wunder; Xiuran Yin; Jenny Wendt; Tim Richter-Heitmann; Susann Henkel; Susana Vázquez; Marcus Elvert; Walter Mac Cormack; Michael W. Friedrich
• Keywords: Detritus

Colonization of newly ice-free areas by marine benthic organisms intensifies burial macroalgae detritus in Potter Cove coastal surface sediments (Western Antarctic Peninsula). Thus, fresh and labile macroalgal serves as primary organic matter (OM) source for microbial degradation. Here, we investigated the effects on post-depositional iron reduction using sediment incubations amended with pulverized OM source, acetate product degradation lepidocrocite reactive oxide to mimic situ conditions. Humic substances analogue anthraquinone-2,6-disulfonic acid (AQDS) was also added some treatments simulate potential electron shuttling. Microbial promoted further enhanced up 30-folds AQDS. Notably, while amendment alone did not stimulate reduction, adding did. Acetate, formate, lactate, butyrate propionate were detected fermentation products from By combining 16S rRNA gene sequencing RNA stable isotope probing, reconstructed food chain degraders reducers. Psychromonas, Marinifilum, Moritella, Colwellia fermenters such lactate. Members class deltaproteobacteria including Sva1033, Desulfuromonas, Desulfuromusa together Arcobacter (former phylum Epsilonbacteraeota, now Campylobacterota) acted dissimilatory Our findings demonstrate that increasing an fjord affected glacier retreat early diagenetic processes reduction. Under scenarios global warming, active populations identified above will expand their environmental function, facilitate remineralisation, contribute increased release CO2 sediments. Such indirect consequences glacial are often overlooked but might, a regional scale, be relevant assessment future nutrient carbon fluxes.