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Controls on the microbial diagenesis of carbon compounds and the preservation of sedimentary carbon as archives of past environmental change 
Convener: Camille Thomas  | Co-conveners: Daniel Ariztegui , Mark Alexander Lever , Patricia Roeser , Mónica Sánchez-Román 
Marine and lacustrine sediments are used to reconstruct paleoclimatic conditions, and to better understand how carbon has been cycled from primary production to organic matter transport, recycling and burial. This once buried carbon is now burnt and released to the atmosphere as green-house gases leading to the known global warming our planet is experiencing. Therefore, a tremendous effort is realized by scientists in various disciplines and different backgrounds to understand the fate of carbon compounds, from its deposition as sedimentary organic matter to its potential release as green-house gas. In sedimentary environments, these steps are mostly mediated by microbes and constitute key stages that must be disentangled to investigate past environmental changes. Within this session, we invite all contributions that are willing to understand the parameters controlling microbial diagenesis of carbon compounds and subsequent preservation of sedimentary carbon within sedimentary archives. They encompass differential degradation of organic matter, changes in redox states of key elements like sulfur, iron or manganese, and dissolution and precipitation of mineral phases such as carbonates. Approaches involving organic matter characterization (biomarkers), isotope biogeochemistry and omics methods are very welcome, just as investigations that advance our understanding of microbial activity in a sedimentary framework (mineral-microbe interactions) and biomineralization processes through in-situ or ex-situ experiments.
We hope to gather a range of pluridisciplinary contributions that will allow to reinforce the cooperation between microbiologists, geochemists and sedimentologists in lake and ocean sediment studies.