| 引用本文: | 龙宜澧,王婷,刘星星,孙有斌.2026.湖泊沉积中有机碳的气候环境意义[J].地球环境学报,17(4):909-929 |
| LONG Yili,WANG Ting,LIU Xingxing,SUN Youbin.2026.Climatic and environmental implications of organic carbon in lake sediments[J].Journal of Earth Environment,17(4):909-929 |
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| 湖泊沉积中有机碳的气候环境意义 |
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龙宜澧1，2，王婷1，3，刘星星1，孙有斌1
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1.中国科学院地球环境研究所 黄土科学全国重点实验室，西安 710061 ；2.中国科学院大学，北京 100049 ；3.湖北工程学院 土木工程学院，孝感 432000
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| 摘要: |
| 湖泊是陆地生态系统中有机碳储存的重要场所，在全球碳循环中扮演关键角色。现代过程研究表明，进入湖泊的有机碳中仅约10%被永久埋藏，大部分通过矿化作用以CO2和CH4形式返回大气。有机碳埋藏效率主要受水热组合调控，湖泊有机碳含量（TOC）对陆源输入和湖泊自生生产力变化响应敏感，是重建区域气候变化的有效代用指标。全球多条跨越百万年的湖泊记录显示，TOC含量在冰期-间冰期尺度上波动显著，在水热条件良好的间冰期普遍升高，反映了流域内生物量和湖泊生产力的同步增强。东亚地区末次冰消期以来的湖泊有机碳记录进一步揭示了西风-季风系统的时空演变：东亚夏季风自14 ka左右开始增强，全新世早期季风由南向北推进，中全新世达到最盛期，晚全新世逐渐减弱；印度季风区约在13 ka开始增强，中全新世最为湿润；西风影响区全新世早期干旱，中晚全新世湿度逐渐增加，湿润期明显晚于季风区。青藏高原及其过渡带湖泊记录则呈现出西风与季风共同作用的复杂响应模式。总体而言，湖泊沉积有机碳含量是流域水热条件、植被生产力与湖泊保存环境综合作用的敏感指标，但不同区域对温度与降水变化的定量响应机制仍需进一步研究。 |
| 关键词: 湖泊 有机碳 气候环境意义 |
| DOI：10.7515/JEE2024057 |
| CSTR：32259.14.JEE2024057 |
| 分类号: |
| 基金项目:国家自然科学基金项目（42494910，42177429）；中国科学院青年创新促进会（2023428）；黄土科学全国重点实验室开放基金（SKLLQG2333） |
| 英文基金项目: |
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| Climatic and environmental implications of organic carbon in lake sediments |
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LONG Yili1，2，WANG Ting1，3，LIU Xingxing1，SUN Youbin1
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1.State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061 , China ；2.University of Chinese Academy of Sciences, Beijing 100049 , China ；3.School of Civil Engineering, Hubei Engineering University, Xiaogan 432000 , China
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| Abstract: |
| Background, aim, and scope Lakes represent major organic carbon reservoirs within terrestrial ecosystems and perform a critical function in the global carbon cycle. Modern studies indicate that only approximately 10% of the organic carbon delivered to lakes is permanently buried, whereas the majority undergoes remineralization and is released back to the atmosphere as CO2 and CH4. Under ongoing global warming and rising atmospheric CO2 concentrations, understanding the fate of lacustrine organic carbon is essential for evaluating carbon-cycle feedbacks to climate change. The burial efficiency of organic carbon is strongly modulated by hydrothermal conditions, and total organic carbon (TOC) content in lake sediments is sensitive to both terrigenous inputs and autochthonous productivity, rendering it a valuable proxy for regional paleoclimate reconstructions. However, robust interpretation of TOC records requires strengthened modern and geological process studies and rigorous multi-proxy cross-validation. To date, most research has focused on the last glacial period, leaving orbital-scale patterns and regional syntheses insufficiently addressed. This paper aims to clarify the transport, burial, and climatic controls of lacustrine organic carbon by integrating modern limnological processes and long-term sedimentary records. Materials and methods We reviewed modern processes governing organic carbon sources, transport pathways, preservation conditions, and burial efficiency. To assess spatiotemporal climatic responses, we compiled long-term, continuous lacustrine TOC records spanning more than one million years with reliable chronologies, including those from Lake El’gygytgyn, Lake Ohrid, Lake Malawi, and Lake Heqing. For East Asia, we selected 13 well-dated, high-resolution lacustrine and peat records distributed across the East Asian summer monsoon domain, Indian monsoon domain, westerly-influenced areas, and the Tibetan Plateau transition zone. TOC variations were compared with magnetic susceptibility, Rb/Sr ratios, carbonate content, and other established climatic proxies to identify responses to changes in temperature, precipitation, and atmospheric circulation. Results TOC content is jointly controlled by organic matter supply, transport processes, and preservation conditions. Lacustrine organic carbon originates mainly from terrestrial higher plants (allochthonous) and aquatic phytoplankton (autochthonous). Favorable hydrothermal conditions enhance terrestrial biomass and lake primary productivity, increasing organic carbon input. Rapid sedimentation, weak hydrodynamics, and anoxic bottom waters reduce organic matter oxidation and facilitate burial. The dominant climatic driver differs regionally: tropical lakes are mainly controlled by precipitation, high-latitude lakes by temperature, and mid-latitude lakes by combined temperature-precipitation effects. TOC values consistently rise under warm-wet conditions and decline under cold-dry regimes, indicating that TOC sensitively integrates signals of catchment productivity, lake ecosystem status, and depositional preservation. These results confirm that TOC is a reliable proxy with clear climatic and environmental significance. Discussion On orbital timescales, global long-term lacustrine records show pronounced glacial-interglacial TOC oscillations, with persistently high values during warm-wet interglacials (e.g., Marine Isotope Stage 11), reflecting synchronous increases in terrestrial and aquatic productivity. Since the last deglaciation, East Asian TOC records reveal distinct spatiotemporal shifts in the westerly-monsoon system. The East Asian summer monsoon intensified at approximately 14 ka, expanded northward in the early Holocene, peaked in the mid-Holocene, and gradually weakened in the late Holocene. The Indian monsoon strengthened around 13 ka and reached maximum humidity during the mid-Holocene. By contrast, westerly-dominated regions were arid in the early Holocene and became increasingly humid in the middle to late Holocene, with a moistening trend that lagged significantly behind monsoon regions. The Tibetan Plateau and adjacent transition zones show complex responses to the combined effects of westerly and monsoon circulations. Comparisons with other proxies (e.g., biogenic silica, Rb/Sr) indicate that TOC is more sensitive to strong climatic signals (e.g., interglacial optima) than to weak events. Conclusions Lake-sediment TOC acts as a sensitive integrator of catchment hydrothermal conditions, vegetation productivity, and lacustrine preservation environments. Globally, TOC records clearly reflect glacial-interglacial cycles and show heightened sensitivity to climate change during warm and humid interglacials. In East Asia, TOC effectively documents the spatiotemporal evolution of the westerly-monsoon system since the last deglaciation, capturing asynchronous advances and retreats of these major circulation systems: monsoon regions show an early-middle Holocene humidity optimum, while westerly regions display a delayed middle-late Holocene wetting trend. The Tibetan Plateau and its margins record complex interactions between westerly and monsoon forcings. Recommendations and perspectives TOC in lake sediments is a sensitive indicator of watershed environmental and climatic change. To improve organic matter source discrimination and climatic calibration, future work should strengthen modern process studies and apply multi-proxy approaches (e.g., compound-specific carbon isotopes and lipid biomarkers). Expanding long, well-dated lacustrine records from climatically sensitive and understudied regions will greatly enhance the reliability of TOC-based paleoclimatic reconstructions. These efforts are critical for deepening understanding of continental carbon-cycle dynamics and for better predicting lake ecosystem responses under ongoing global change. |
| Key words: lakes organic carbon climate and environment implications |
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