Abstract The elemental (TOC, TN and C/N) and carbon isotope (Δ14C and δ13C) compositions of organic matter were measured in different grain size fractions of particles transported by the Yellow River and surface sediments in the Bohai Sea and the Yellow Sea. In the riverine particle and sediment samples, high OC contents were associated with small grain size fractions consisting mainly of clay minerals. The δ13C and Δ14C values of the bulk riverine particulate organic carbon (POC) collected from the Lijin and Xiaolangdi sites were relatively constant but varied significantly (−21.9‰ to −26.0‰ and −325‰ to −620‰, respectively) among the different size fractions. In comparison, large spatial variations in δ13C (−20.6‰ to −24.5‰) and Δ14C (−188‰ to −646‰) values, which increased seaward due to the difference in source carbon, were found for bulk TOC Δ14C preserved in the surface sediments, but no significant differences were observed among the values in the different size fractions in most sediments. The different carbon isotopic values of the riverine POC and sedimentary TOC reflect differences in the sources, degradation and cycling time scales of the OC. The Yellow River exports very old (5220 ± 295 yrs) POC that is much older than the TOC (2457 ± 676 yrs) preserved in the surface sediments in the Bohai and Yellow seas. Calculations using a dual-isotope three end-member model indicate that pre-aged soil OC and ancient fossil OC represent major proportions (57 ± 16% and 30 ± 8%, respectively) of the riverine POC and that terrestrial biomass OC represents a minor proportion (13 ± 11%). The drainage environment of the river plays important roles in controlling the sources and ages of the riverine POC. In contrast, the TOC in the grain size fractions of the surface sediments in the Bohai and Yellow seas is dominated by marine-derived modern OC (47 ± 13%), followed by pre-aged soil OC (29 ± 9%) and ancient fossil OC (25 ± 14%). The ages of the TOC are determined mainly by the source input, rapid sedimentation, sediment minerology and decomposition of OC during early diagenesis in these large river-influenced marginal seas.

中文翻译：

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黄河输送颗粒和海岸沉积物不同粒度级有机碳的来源和放射性碳年龄

摘要 测定了黄河输送的颗粒和渤海、黄海表层沉积物的不同粒度级分有机质的元素（TOC、TN和C/N）和碳同位素（Δ14C和δ13C）组成。在河流颗粒和沉积物样品中，高 OC 含量与主要由粘土矿物组成的小粒度部分有关。从利津和小浪底采集到的大块河流颗粒有机碳 (POC) 的 δ13C 和 Δ14C 值相对恒定，但在不同地区之间差异显着（分别为 -21.9‰ 至 -26.0‰ 和 -325‰ 至 -620‰）大小分数。相比之下，δ13C（-20.6‰至-24.5‰）和Δ14C（-188‰至-646‰）值的空间变化较大，由于源碳的差异，向海增加，表层沉积物中保存的大量 TOC Δ14C 被发现，但在大多数沉积物中不同尺寸分数的值之间没有观察到显着差异。河流POC和沉积TOC的不同碳同位素值反映了OC来源、降解和循环时间尺度的差异。黄河输出非常古老（5220±295 年）的 POC，比保存在渤海和黄海表层沉积物中的 TOC（2457±676 年）古老得多。使用双同位素三端元模型计算表明，老化前土壤 OC 和古代化石 OC 代表河流 POC 的主要比例（分别为 57 ± 16% 和 30 ± 8%），而陆地生物量 OC 代表次要比例（13±11%）。河流的排水环境在控制河流POC的来源和年龄方面起着重要作用。相比之下，渤海和黄海表层沉积物粒度级分中的 TOC 以海洋来源的现代 OC（47±13%）为主，其次是早龄土壤 OC（29±9%）和古代化石 OC (25 ± 14%)。在这些受河流影响的大型边缘海中，TOC 的年龄主要由源输入、快速沉积、沉积物矿物学和早期成岩过程中 OC 的分解决定。