| 引用本文: | 韩瑞超,汪勇,马再园,金院,吴立.长江下游升金湖过去千年有机碳埋藏变化及其影响因素.湖泊科学,2025,37(2):675-688. DOI:10.18307/2025.0251 |
| Han Ruichao,Wang Yong,Ma Zaiyuan,Jin Yuan,Wu Li.Changes in organic carbon accumulation and its influencing factors over the past millennium in Lake Shengjin, lower reaches of the Yangtze River. J. Lake Sci.2025,37(2):675-688. DOI:10.18307/2025.0251 |
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| 摘要: |
| 选择我国长江下游平原浅水湖泊升金湖86 cm沉积岩芯为研究对象，在可靠深度-年代模型基础上，通过沉积物质量累积速率(SAR)和总有机碳(TOC)含量计算升金湖过去千年有机碳埋藏速率变化；利用C/N与正构烷烃指标指示升金湖有机碳来源变化，并结合升金湖流域气候环境与人类活动历史记录探究该湖近千年有机碳埋藏的影响因素。研究结果表明：升金湖过去千年有机碳埋藏速率呈增加趋势，平均有机碳埋藏速率约为24.77 g/(m2·a)，总有机碳储量约为3.33 Tg (1 Tg=1012 g)。根据升金湖有机碳埋藏速率变化特征，本研究将其划分为4个阶段：阶段Ⅰ：1000—1350 A.D.，有机碳埋藏速率较低但波动较大；阶段Ⅱ：1350—1600 A.D.，有机碳埋藏速率有所下降，为近千年来的最低水平；阶段Ⅲ：1600—1850 A.D.，升金湖有机碳埋藏速率迅速上升后，保持在较高水平；阶段Ⅳ：1850—2000 A.D.，升金湖有机碳埋藏速率继续上升，达到近千年来最高水平。进一步研究发现，升金湖有机碳埋藏速率主要受TOC含量的影响，与质量累积速率相关性较弱；阶段Ⅰ(1000—1350 A.D.)与阶段Ⅱ(1350—1600 A.D)沉积物有机质主要来源于内源水生植被，沉积环境以自然沉积为主；TOC含量增加推测与降水增多、温度下降有关，因此自然因素是此阶段湖泊有机碳埋藏速率变化的主控因素。阶段Ⅲ(1600—1850 A.D)与阶段Ⅳ(1850—2000 A.D.)沉积物有机质主要来源于外源陆生高等植被，沉积环境受人类活动影响更为强烈，如流域人口大量增长、耕地面积增加、化肥农药使用频繁等，给湖泊流域带来了大量的有机质输入，进而显著影响湖泊有机碳埋藏速率的变化。 |
| 关键词: 碳埋藏 升金湖 湖泊沉积物 过去千年 人类活动 |
| DOI：10.18307/2025.0251 |
| 分类号: |
| 基金项目:国家自然科学基金项目(41771228)；安徽师范大学校博士启动金项目(2017XJJ36)联合资助 |
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| Changes in organic carbon accumulation and its influencing factors over the past millennium in Lake Shengjin, lower reaches of the Yangtze River |
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Han Ruichao1，2，Wang Yong1，2，Ma Zaiyuan1，2，Jin Yuan1，3，Wu Li1，2
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1.School of Geography and Tourism, Anhui Normal University, Wuhu 241002 , P.R.China ；2.Anhui Key Laboratory of Earth Surface Processes and Regional Response in Yangtze-Huaihe Basin, Wuhu 241002 , P.R.China ；3.State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 211135 , P.R.China
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| Abstract: |
| An 86-cm long sediment core, obtained from Lake Shengjin in the monsoon region of eastern China, served as the material for studying the mechanisms of organic carbon burial in the lake. Based on the reliable depth-age model, the sediment accumulation rate (SAR) and total organic carbon (TOC) were used to calculate the variation of organic carbon accumulation rate (OCAR) in the lake over the past millennium. The C/N ratio and n-alkanes proxies were used to indicate the sources of organic carbon. Then the influencing factors of the OCAR are discussed in terms of the organic matter source, historical climate change and human activities. Results reveal a general increasing trend of OCAR during the past millennium, with the average OCAR of approximately 24.77 g/(m2·a), and the total organic carbon storage of 3.33 Tg (1 Tg=1012 g). Specifically, the OCAR during the past millennium can be divided into four stages: Stage Ⅰ: 1000-1350 A.D., OCAR was generally low but fluctuated significantly; Stage Ⅱ: 1350-1600 A.D., OCAR decreased to the lowest level during the past millennium; Stage Ⅲ: 1600-1850 A.D., OCAR increased rapidly and maintained a relatively high level; Stage Ⅳ: 1850-2000 A.D., OCAR increased continuously and then reached the highest level. Our results further demonstrate that the sedimentary organic matter in the first two stages is mainly derived from endogenous aquatic plants. The increase in TOC content is speculated to be related to the increase in precipitation and the decrease in temperature, and the decrease in mass accumulation rate may be due to the stable hydrological conditions of the lake. Therefore, we suppose that the natural factors mainly controlled the variations of OCAR in the lake during Stages Ⅰ and Ⅱ. During Stage Ⅲ (1600-1850 A.D.) and Stage Ⅳ (1850-2000 A.D.), our result suggests that the sedimentary organic matter was mainly derived from exogenous terrestrial plants, and the sedimentary environment was more strongly influenced by human activities. The massive growth of population, the increase of cultivated land, as well as the frequent use of chemical fertilizers and pesticides, brought a large amount of organic matter into the lake basin. Therefore, we conclude that the variations of OCAR during these two stages were significantly affected by human activities, rather than natural factors. |
| Key words: Carbon accumulation Lake Shengjin lake sediment past millennium human activity |
