Microbe-Metal Interactions in Sediments

Abstract

Microbial contributions to the solid phase partitioning of metals in sediments span a continuum of sorption and precipitation reactions. Passive involvement of microorganisms in these processes relates to the behavior of individual microbial cells as sorbents of dissolved metals and heterogeneous nucleation templates for authigenic mineral deposition. Active microbial intervention is also possible with metal precipitation being induced in response to metabolic production of reactive inorganic ligands such as sulfide, or through enzyme mediated changes in metal redox state. The deposition of authigenic iron-aluminum-silicates and metallic gold on microbial surfaces comprise unique examples of passive microbe-metal interactions, while the reductive precipitation of uranium is representative of metabolic metal precipitation by microorganisms.