Speaker
Description
Constraining the sources, transport, and burial of OC in marine sediments is of fundamental importance for understanding the carbon cycle on a range of spatial and temporal scales. Marginal seas receive substantial terrestrial inputs from rivers and comprise hotspots for both organic carbon (OC) burial and remineralization. However, much remains unknown about factors that control the sources, transport processes and burial history of OC in response to natural and anthropogenic processes in marginal seas. Here we employ novel approaches of dual carbon isotopic (Δ14C and δ13C) measurements of both bulk OC and especially source-specific biomarkers to gain deeper insights into the fates of terrestrial organic carbon in China marginal sea systems. We systematically assess the characteristics of riverine and marine sediments, quantify the contributions of different-sourced and different aged OC and reveal their spatial distributions, and then constrain the burial efficiencies of terrestrial OC in China marginal seas. We also explore the role of transport processes (e.g., hydrodynamic sorting) in alteration and evolution of OC along the river-estuary-coastal ocean continuum. Our results reveal that estuaries serve as critical zones for OC degradation and aging, which in turn affect OC burial in marginal seas. By applying the same approaches in down-core sediments, we examine the longer-term controls on OC composition, age and burial over centennial to millennial timescales, revealing the distinct variations and mechanisms for terrestrial OC fates in China marginal seas. Overall, these findings suggest both sources and hydrodynamic processes during transport exert strong influence on the fate of OC, with important implications for the role of river-dominated marginal seas in the global carbon cycle.
| Student Submission | No |
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