The Distribution of Sedimentary Organic Matter and Implication of Its Transfer from Changjiang Estuary to Hangzhou Bay, China

Abstract

In this study, a comparison was made between the Changjiang Estuary and the Hanghzou Bay, in terms of the sources and diagenesis of the sedimentary organic matter (OM). To achieve this purpose, surface sediments from the estuary and bay were analyzed for lignin-derived phenols, stable carbon isotope and TOC/TN (total organic carbon/total nitrogen) molar ratio. The signal of landderived OM decreased, and the vanillic acid to vanillin ratio, (Ad/Al)v, increased with increasing distance from the Changjiang Estuary and the Hangzhou Bay. These results corresponded with the contribution of the terrigenous OM from the rivers to the coastal zone, and the predominance of marine OM farther offshore, and that the land-derived OM underwent decomposition during transport along the estuary and bay. It should be noted that besides the Qiantang River, Hangzhou Bay is also receiving more than half of its materials from Changjiang Estuary, which flows into the Hangzhou Bay at the north, and leaves via the southern part of the bay. This important aspect of the hydrological cycle in Hangzhou Bay corresponded to higher Λ (total lignin in mg/100 mg OC), higher TOC and C/N ratios and more elevated (Ad/Al)v and (Ad/Al)s values in the bay than the Changjiang Estuary, thus, rendering the bay as a site for the accumulation and rapid cycling of terrigenous OM.

Effects of Biological Production and Vertical Mixing on Sea Surface pCO2 Variations in the Changjiang River Plume During Early Autumn: A Buoy‐Based Time Series Study

“…The river flux of Changjiang River is more than 20 times that of Qiantang River. In addition, previous hydrological and biomarker research had indicated that CDW may flow into Hangzhou Bay (Qiantang River) and represented the major source of sediment in the Hangzhou Bay (Dai et al, ; Su & Wang, ; Xu et al, ). Thus, Hangzhou Bay water was not considered as an end‐member.…”

Growth of sedimentaryBathyarchaeotaon lignin as an energy source

“…Samples were stored anoxically on ice in gas-tight bags and were transported to the laboratory within 3 h, where they were kept at 4°C until further treatment. The samples were dominated by silt sediment, which is mainly supplied by the Yangtze River (33) and is considered to be rich in terrigenous organic matter (34).…”

StimulatedProrocentrum donghaiensecell growth byin-situmariculture dissolved organic matter

“…(c) C/N ratios (Cai et al, 2016;Liu, 2018;Chen et al, 2019;Zhang et al, 2022). (d) C/N ratios in this study and of surface sediments in some bloom areas (Hu et al, 2014;Chao et al, 2017;Wang et al, 2018;Rodil et al, 2020;Wang, 2020b;Likumahua et al, 2021;Xu, 2022;Beltran-Perez et al, 2023). The text above the column indicates different experimental conditions or areas.…”