Indicators of past hypoxia dynamics: improving long term records by abiotic and biotic proxies

WP 4

Late Quaternary basin, paleoclimatic, and paleooceanographic evolution, and the relation of this evolution to oxygen depletion will be assessed for selected sites (Black Sea, Baltic Sea, Swiss lakes). Methods applied will include high resolution seismic profiling as well as sediment core analysis using a range of inorganic and organic proxies. To determine how oxygen availability changes benthic community structure and ecosystems in general, biodiversity (macrobenthic, meiobenthic, microbial) will be investigated in surficial sediments of the Black Sea from different water depths. Furthermore, this workpackage will aid in the selection of appropriate observatory sites.

• Assess the history of selected sites with respect to basin structure, water level, water flux, and sedimentation
• Investigate high resolution (decadal to centennial) sedimentary records of the spatial and temporal changes in the redox conditions of the water column using inorganic and organic proxies, noble gases, biomarkers, and isotopic signatures
• Analyze past and recent structure of benthic communities and their resilience to oxygen depletion as potential indicators of variation in oxygen concentration
• Study paleoclimate of the systems and their relation to oxygen depletion