The Fate of Terrestrial Organic Carbon in the Marine Environment

Understanding the fate of terrestrial organic carbon (Corg) delivered to oceans by rivers is critical for constraining models of biogeochemical cycling and Earth surface evolution. Corg fate is dependent on both intrinsic characteristics (molecular structure, matrix) and the environmental conditions to which fluvial Corg is subjected. Three distinct patterns are evident on continental margins supplied by rivers: (a) high-energy, mobile muds with enhanced oxygen exposure and efficient metabolite exchange have very low preservation of both terrestrial and marine Corg (e.g., Amazon subaqueous delta); (b) low-energy facies with extreme accumulation have high Corg preservation (e.g., Ganges-Brahmaputra); and (c)…