Lakes are waterbodies, and their organic carbon (OC) depositions are one of the important C pools in the terrestrial ecosystem. The characteristics, size and change of these C pools are closely related to climate issues and human activities. Here Lake Chenghai was chosen as a representative, and the distribution, property and source of OC deposition were systematically investigated using isotopes and chemical biomarkers methods and 24-index indicators. The results showed that distribution pattern of OC deposition could be divided into two types, including a relative stable stage in the bottom layer (48.8-38.4 cm), and an upswing stage in the middle layer (38.4-16.8 cm) and surface layer (16.8-0 cm) of lake sediments, where the OC deposition was stable below 5.00 g m^-2 yr^-1, and increased from 5.00 to 21.87 g m^-2 yr^-1, respectively. The chemical composition of OC deposition showed that the bottom layer had higher aromaticity, hydrophobicity and the relative molecular weight. The three components, i.e. humic acid, fulvic acid and protein-like component, all rose from the bottom to the surface of lake sediment. Plants (47.7–82.0%) were the main OC source. C₃ plants dominated the bottom layer, while microorganisms and algae contributed more to the middle and surface layers. The OC deposition fluctuated largely due to the disturbance from warming and anthropogenic activities. This study is expected to provide comprehensive scientific references for reconstructing OC deposition of plateau lake, and lay a good foundation for preventing and controlling plateau lake eutrophication, and evaluating and reducing carbon dioxide emission in plateau lake.

中文翻译：

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典型高原深湖 150 年的有机碳沉积

湖泊是水体，其有机碳 （OC） 沉积是陆地生态系统中重要的 C 池之一。这些 C 池的特征、大小和变化与气候问题和人类活动密切相关。这里以澄海湖为代表，采用同位素和化学生物标志物法和 24 指数指标系统研究了 OC 沉积物的分布、性质和来源。结果表明：OC 沉积物分布模式可分为两种类型，包括湖泊沉积物底层（48.8—38.4 cm）相对稳定阶段和中层（38.4—16.8 cm）和表层（16.8—0 cm）的上升阶段，其中 OC 沉积稳定在 5.00 g ^{m-2 yr-1} 以下; 和分别从 5.00 克 ^{m-2 yr-1} 增加到 21.87 克。OC 沉积的化学成分表明，底层具有较高的芳香性、疏水性和相对分子量。腐殖酸、黄腐酸和蛋白质样成分 3 种成分均从湖底上升到湖底表面。植物 （47.7–82.0%） 是 OC 的主要来源。C₃ 植物在底层占主导地位，而微生物和藻类对中层和表层的贡献更大。OC 沉积波动主要是由于变暖和人为活动的干扰。本研究可为重建高原湖 OC 沉积提供全面的科学参考，为防治高原湖富营养化、评价和减少高原湖二氧化碳排放奠定良好基础。