Andrew Stack
Georgia Institute of Technology

Title: “Evidence for Young Acidic Water Beneath Mars from Meteorite Studies”

Abstract: Dissimatory iron reducing bacteria (DIRB) couple the oxidation of organic matter and hydrogen to the reduction of ferric iron and a number of toxic metals. Due to the ubiquity of these organisms in terrestrial soils, coastal marine sediments and near-surface groundwater environments, ferric iron is potentially the second most common biological electron acceptor after oxygen. In contrast to soluble electron acceptors, ferric iron minerals generally have low solubilities and thus present an enzymatic challenge to the DIRB. In this talk, the interactions between DIRB and iron (oxy)(hydr)oxide minerals will be discussed. The various respiration mechanisms that the organisms use or may use under different circumstances will be discussed in terms of the controls on the rate of reductive dissolution of the minerals.