Degradation and Aging of Terrestrial Organic Carbon within Estuaries: Biogeochemical and Environmental Implications
Abstract
Estuaries are action zones for organic carbon (OC) degradation and aging. These processes influence the nature of terrestrial OC (OCterr) export and the magnitude of OCterr burial in marginal seas, with important environmental implications such as CO2 release and hypoxia. In this study, we determined the contents and carbon isotopic compositions (C-13 and C-14) of bulk OC and fatty acids (FAs) as well as the sedimentological characteristics of suspended particulate matter (SPM) samples collected from two sites over four seasons and of surface sediment samples from three sites in the Pearl River estuary (PRE) to evaluate processes controlling OCterr degradation and aging along an estuarine gradient. We found that the abundance-weighted average C(24-32)FA C-14 ages increased by an average of similar to 1170 years for SPM and by an average of similar to 3440 years in PR/PRE sediments, along the similar to 60 km PRE transect. These increases in the FA age coincided with an 86% decrease in the corresponding mineral surface area-normalized FA loading along the sediment transport pathway, implying that selective degradation of labile and younger OC resulted in apparent OC aging. These measurements reveal an important shift in the nature of OC, with implications for biogeochemical cycling within estuaries and for regional environmental changes. Mehr anzeigen
Publikationsstatus
publishedExterne Links
Zeitschrift / Serie
Environmental Science & TechnologyBand
Seiten / Artikelnummer
Verlag
American Chemical SocietyThema
Physiology; Degradation; Geological materials; Carbon; Scanning probe microscopyOrganisationseinheit
03868 - Eglinton, Timothy I. / Eglinton, Timothy I.
08619 - Labor für Ionenstrahlphysik (LIP) / Laboratory of Ion Beam Physics (LIP)
Förderung
163162 - Climate and Anthropogenic PerturbationS of Land-Ocean Carbon tracKs (CAPS-LOCK2) (SNF)
184865 - Climate and Anthropogenetic PertubationS of Land-Ocean Carbon tracKs (CAPS-LOCK3) (SNF)