Characteristics of Sedimentary Organic Matter in Tidal Estuaries: A Case Study from the Minjiang River Estuary

作者：Shuilan Wu, Shuqin Tao, Xiang Ye, Aijun Wang, Zitong Liu, Ran Chang, Haoshen Liang, Haiqi Li, Yuxin Yang, Wangze Zhang, James T. Liu · 发表于：Water · 年份：2023 · DOI：10.3390/w15091682 · 被引用次数：24 · 研究领域：Marine and coastal ecosystems、Coastal wetland ecosystem dynamics、Isotope Analysis in Ecology

As one of the main interfaces of the Earth system, estuaries show the strongest land–sea interaction in the carbon cycle, which links terrestrial ecosystems to the marginal sea. Furthermore, estuaries are considered as one of the most active intermediate reservoirs for both terrestrial and marine matter due to complex hydrodynamic processes regulated by the river runoff, wave and tide. Processing of organic matter (OM) in tidal estuaries modifies its transfer and transformation from the river to the sea, so studies of on the source and distributions of estuarine OM can help us understand the behavior of production, exchange, transport and burial of diverse OM within this transition zone before entering the marginal sea. In this paper, we took the Minjiang River Estuary (MRE) as a typical system in which there is strong influence of the tide. The source, composition and spatial distribution of OM in surface sediments of MRE were deciphered based on multiple organic geochemical properties for source-specific biomarkers (n-alkanes, n-alkanols, sterols) and bulk OM. Results show that sedimentary organic components were negatively correlated with sediment grain size, which indicates fine particles such as silt and clay are the major carriers of the OM signals in tidal estuaries. Source-specific biomarker proxies indicate that in terms of source diversity the sedimentary OM in the MRE shows mixed signals of terrestrial and marine sources, and the proportion of terrestrial OM decrea...