A4: Biogeochemical and geomicrobial studies of modern and ancient microbial communities

(J. M. Hayes, Woods Hole; K.-U. Hinrichs, Bremen)

Throughout Earth’s history, microbial processes have been influencing the cycles and global budgets of many chemical elements. Triggered by recent innovations in isotopic and molecular techniques, great progress has been made in our understanding of microbial communities and processes in both ancient and modern marine environments. Prominent examples include investigations of the early biosphere with fossil biomarkers, the use of mass-dependent isotope fractionations for constraining the role of the biosphere in cycling of S and O in the Precambrian, and concerted applications of modern molecular and geochemical tools that provide an increasingly more complete picture of the microbial network of transformations of energy and matter in the modern ocean. We encourage submissions from geochemists and microbiologists alike who study the role, function, and environmental significance of ancient and modern microbial communities.