The nature, timescale, and efficiency of riverine export of terrestrial organic carbon in the (sub)tropics: Insights at the molecular level from the Pearl River and adjacent coastal sea
ORCID: https://orcid.org/0000-0001-5138-564X, Hefter, Jens ORCID: https://orcid.org/0000-0002-5823-1966, Kusch, Stephanie, Grotheer, Hendrik ORCID: https://orcid.org/0000-0003-0207-3767, Schefuß, Enno and Jia, Guodong
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Tropical and subtropical rivers deliver large quantities of terrestrial organic carbon (OCterr) to the ocean, acting as a crucial part of the global carbon cycle, but little is known about the timescale and efficiency of its transport to and in the adjacent coastal sea. Here we examined source-specific biomarker (fatty acids, FAs) contents and isotope compositions in surface sediments in an alongshore transect southwestward from the Pearl River mouth. The C28+30, rather than other long-chain saturated FAs, were found to be the most representative for OCterr, and a plant wax mean age of 3060 ±90 yr (resulting from protracted storage) was estimated in the Pearl River watershed from the 14C age of C28+30FA in a river mouth sample. A compilation of plant wax mean ages in global (sub)tropical river systems including this study suggests that regional differences in climate and morphology may have a limited impact on plant wax mean ages in (sub)tropical regions. A four-source mixing model based on bulk OC and biomar
ORCID: https://orcid.org/0000-0001-5138-564X, Hefter, Jens ORCID: https://orcid.org/0000-0002-5823-1966, Kusch, Stephanie, Grotheer, Hendrik ORCID: https://orcid.org/0000-0003-0207-3767, Schefuß, Enno and Jia, Guodong
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