Topic IV - Critical zone and integrated approaches > IV-1-Biogeochemical cycles in the subsurface: molecular and mineral proxies for integrated lacustrine studies

Conveners

1. Maïlys Picard (Umea University, Sweden)
2. Lotta Purkamo (Geological Survey of Finland GTK)
3. Aurèle Vuillemin (GFZ Potsdalm, Germany)
4. Camille Thomas (University of Bern, Switzerland)

Microorganisms are abundant and diverse in inland waters, where they contribute significantly to global element fluxes through regulation of biogeochemical cycles. Lake sediment accumulation over geologic timescales records past climatic and trophic conditions, forming stratified archives. By regulating sediment biogeochemical cycles, the microbial biosphere hosted in the lacustrine subsurface drives essential feedback in terms of benthic releases or sediment sequestration, with significant potential to influence environmental conditions or alter their sedimentary records. At present, the relationship between lake sediments as microbial habitats and biogeochemical processes in bottom waters, at the sediment-water interface and in the subsurface remain elusive as lakes represent dynamic ecosystems.

This session invites contributions investigating microbial processes in lake sediments. It is meant to encompass shallow biogeochemical cycles, as well as deeper, slower processes that lead to long-term organic matter remineralization, mineral dissolution and precipitation, and proxy disturbance. Indicative tools may include molecular-based methods (e.g. nucleic acids, proteins, lipids), isotopic fingerprinting of sediment fractions, biogeochemical modeling, and any integrative approach that bolsters new understanding of biological-geological interactions in lacustrine ecosystems. Early career scientists are particularly welcome to contribute to the session.