Microbial carbonate precipitation in the ocean has played a fundamental role in shaping Earth surface environments through geologic time, from documenting the earliest occurrence of life on Earth to being a crucial carbon sink in present-day methane cycling. Marine microbial carbonates encompass a wide variety of precipitates, from shallow-water microbialites, to deep-water mud mounds and hydrocarbon-seep deposits. They are an integral part of the sedimentary rock record, recording changes in environmental conditions and (bio)geochemical processes during key intervals of Earth history. Trace elements are widely used tools to recover information from the microbial carbonate archive, reconstructing the evolution of paleoenvironments and the (micro)biological ecosystems that shaped them. The use of trace element patterns in concert with stable and radiogenic isotopic records and the molecular fossil inventory of carbonates is at the forefront in identifying microbial metabolic processes in ancient habitats, and to reconstruct the overall chemical evolution of Earth’s hydrosphere and atmosphere.
This session welcomes contributions that reconstruct marine environmental change and identify the composition of microbial habitats using microbially-derived carbonates as an archive from the recent to the ancient past, applying traditional, non-traditional, stable and radiogenic isotope systems (e.g. Li, Mg, Cr, Fe, Sr, Mo, Cd, Ni, Nd, Pb, U), redox-sensitive and bio-essential trace elements, as well as lipid biomarkers. We appreciate contributions that apply these tools, and combine them with mineralogical, sedimentological, and paleontological records in order to unravel past and present climate and environmental changes. We also encourage submissions relating to field, laboratory, and experimental work that establish and calibrate new proxies for microbial habitat and metabolic process reconstruction.