T218 Geobiology of Earth-Life Systems II

Tuesday, 27 September 2016
1:30 PM - 5:30 PM
Room 503

ZOMBIE MINES AND BRAIN BIOFILMS: ACID MINE DRAINAGE IMPACT AND IMPLICATIONS FOR THE ARCHEAN-PALEOPROTEROZOIC TRANSITION

Paper number: T218-10
Program: Technical Sessions
Time: 3:50 PM – 4:05 PM

Authors

Abstract

Streams impacted by acid mine drainage (AMD) represent local environmental and ecological disasters; however they may also present an opportunity to study microbial communities in environments analogous to past conditions. Following the emergence of oxygenic photosynthesis, atmospheric O2 generated by Cyanobacteria came into contact with streams and rivers on continental surfaces replete with detrital pyrite, producing ideal conditions for pyrite oxidation similar to that found at modern AMD-impacted sites. We sampled sites that exhibited a range of AMD-impact (e.g., pH from 2.1 to 7.9, Fe2+ from 5.2 mmol/L to below detection limits, SO42- from 0.3 to 52.4 mmol/L) and found i) nearly all analytes correlated to sulfate concentration, ii) all sites exhibited the presence (and even predominance) of a single microbial taxon most closely related to Ferrovum myxofaciens which is capable of nitrogen fixation and chemoautotrophy via Fe2+ oxidation, iii) signs of potential inorganic carbon limitation and nitrogen cycling. From these findings, we present a conceptual model of continental surfaces during the Paleoproterozoic. Our model suggests a connection between O2 production in the ocean to AMD-type pyrite oxidation on continental surfaces through a negative feedback loop. Sulfate production through oxidative weathering of terrestrial surfaces would be delivered to near-shore environments which in turn drove euxinia through the action of sulfate reducing organisms. Thus, the result of the model is a potential negative feedback loop/throttle for O2 production during the Paleoproterozoic.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-283167

© Copyright 2016 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.