基于单体分子化合物碳-14技术的边缘海有机碳转化、迁移与埋藏过程研究

边缘海有机质的横向搬运作用是海洋有机碳循环过程中的重要环节。然而，目前缺乏关键技术手段研究横向搬运作用对有机碳转化、迁移与埋藏过程的影响，限制了海洋有机碳循环理论的进一步发展。本项目利用先进的单体分子化合物碳-14测定分析技术，分别对黄河口、山东半岛沿岸以及南黄海沉积中心区表层沉积物中微生物来源的磷脂脂肪酸、陆源的木质素以及海源的长链烯酮三种生物标志物开展研究。通过系统测定不同粒度下沉积物中这三种生物标志物的天然放射性碳-14年龄，分析研究横向搬运作用对有机碳转化、迁移与埋藏过程的控制机理。本项目旨在：1）揭示悬浮搬运作用对微生物参与的有机碳转化过程的控制机制；2）估算陆源有机质沿边缘海经典传输路径的横向搬运时间；3）验证横向搬运作用对海源有机碳埋藏异质性的影响。本项目将对厘定边缘海有机碳埋藏以及应用海洋有机地球化学指标有重要的指示意义。

Lateral transport process of sedimentary organic carbon constitutes a key component of oceanic carbon cycle. However, it still remains limited about cutting-edge technologies and comprehensive studies focusing on influence of the lateral transport in transformation, distribution, and burial of organic carbon, hindering the further theoretical development about marine organic carbon cycle in marginal seas. By virtue of the state-of-the-art compound specific radiocarbon analysis, this project will examine the microbe-derived, terrestrial, and marine biomarkers retrieved from surface sediments collected from the Yellow River Mouth, Shandong Peninsula mud belt, and the depocenter of Southern Yellow Sea, respectively. The study will analyze the radiocarbon ages of bacterial phospholipid-linked fatty acids, lignin, and alkenones in the differentiated grain size fractions of surface sediments, in order to decipher the functional roles of lateral transport process in transformation, distribution, and burial of organic carbon in the marginal seas. The objectives of project are to 1) reveal the mechanic controls of hydrodynamics on microbial transformation of organic carbon, 2) constrain the lateral transport time of terrestrial organic carbon along a classic transport pathway, 3) examine the heterogeneity of marine organic carbon spatially accumulating in the depocenter. This project would exert a boarder and deeper significance in burial of organic carbon and application of organic geochemical proxy in marginal seas.