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Origins, transport and transformation of organic matter in the coastal margin

The coastal margin accounts for up to 90% of organic matter (OM) burial in the global ocean, forming a major component of the global carbon cycle and budget (Bauer et al., 2013). There has been longstanding general agreement that continental shelves represent the largest sink of both terrestrial and marine OM in the global ocean, but our understanding of the spatial and process complexity of this region continues to evolve. For example, 70% of the continental shelf are covered by sandy sediments and characterized by low OM and high pore water dissolved oxygen concentration. Low organic carbon content of sandy sediments is not the consequence of sediment inactivity, but rather the consequence of high organic carbon turnover. The oxygen dynamics are fairly well understood in the coastal sandy sediments, but the organic matter pathways remain unclear.

Aims of this project:
1) Trace origins and transport of OM in the different zones of coastal margins using stable carbon isotope (δ13C) and radiocarbon isotope (F14C) content as well as specific biomarkers.
2) Investigate the biogeochemical cycling of dissolved and particulate OM at coastal sandy sediments by combining ultra-high resolution mass spectrometry (FT-ICR-MS) to the use of flow-through reactors connected to O2 sensors.

By collaboration with Marum (Bremen), AWI (Bremerhaven), ICBM (Oldenburg) and MPI (Bremen), we aim to detailed understanding of OM dynamics in coastal margins and their significant roles in global carbon cycle.