Filamentous sulfur bacteria preserved in modern and ancient phosphatic sediments: implications for the role of oxygen and bacteria in phosphogenesis

摘要: Marine phosphate-rich sedimentary deposits (phosphorites) are important geological reservoirs for the biologically essential nutrient phosphorous. Phosphorites first appear in abundance approximately 600 million years ago, but their proliferation at that time is poorly understood. Recent marine phosphorites spatially correlate with habitats of vacuolated sulfide-oxidizing bacteria store polyphosphates under oxic conditions to be utilized sulfidic conditions. Hydrolysis stored polyphosphate results rapid precipitation mineral apatite—providing a mechanism explain association between modern and these bacteria. Whether sulfur were formation ancient has been unresolved. Here, we present remains partially encrusted apatite, providing evidence bacterially mediated phosphogenesis can rapidly permineralize perhaps other types organic remains. We also describe filamentous microfossils resemble from two major phosphogenic episodes geologic record. These contain sulfur-rich inclusions may represent relict globules, diagnostic feature findings suggest bacteria, which known mediate apatite sediments, certain settings least last years. If polyphosphate-utilizing played role phosphorites, requirements oxygen, or oxygen-requiring metabolites such as nitrate, might temporal correlation appearance globally distributed increasing oxygenation Neoproterozoic oceans.