RT Journal Article SR Electronic T1 A biological source of marine sedimentary iron oxides JF bioRxiv FD Cold Spring Harbor Laboratory SP 108621 DO 10.1101/108621 A1 Jacob P. Beam A1 Jarrod J. Scott A1 Sean M. McAllister A1 Clara S. Chan A1 James McManus A1 Filip J.R. Meysman A1 David Emerson YR 2017 UL http://biorxiv.org/content/early/2017/04/28/108621.abstract AB The biogeochemical cycle of iron is intricately linked to numerous element cycles. Although reductive biological processes that bridge the iron cycle to other element cycles are established, little is known about microbial oxidative processes on iron cycling in sedimentary environments—resulting in the formation of iron oxides. Here, we show that a major source of sedimentary iron oxides originates from the metabolic activity of iron-oxidizing bacteria from the class Zetaproteobacteria, stimulated by burrowing animals in coastal sediments. Zetaproteobacteria were estimated to be a global total of 1026 cells in coastal, bioturbated sediments and would equate to an annual production of approximately 7.9 x 1015 grams of sedimentary iron oxides—twenty-five times larger than the annual flux of iron oxides by rivers. These data suggest that iron-oxidizing Zetaproteobacteria are keystone organisms in marine sedimentary environments given their low numerical abundance; yet exert a profound impact via the production of iron oxides.