| 摘要: |
| 湖泊中腹足类壳体碳酸盐的碳同位素与水体溶解无机碳密切相关，是研究区域湖泊水体碳循环的重要材料之一。滇中地区湖泊众多，然而该区域湖泊中水体溶解无机碳的变化特征仍不清楚。孟氏螺蛳壳体为滇中湖泊特有属，本文通过对杞麓湖现生孟氏螺蛳壳体采集，并对其壳体沿生长方向开展碳酸盐δ13C测试，尝试利用孟氏螺蛳壳体δ13C分析杞麓湖水体溶解无机碳变化的变化特征。研究结果表明：（1）孟氏螺蛳壳体δ13Cshell与壳体生长环境密切相关，QLH-A与QLH-B在母体环境中生长其δ13Cshell平均值为分别为?3.78‰与?5.55‰，变化范围幅度分别为2.07‰与3.03‰；在湖泊水体环境中生长时其δ13Cshell平均值为分别为?2.9‰与?3.28‰，变化范围幅度分别为1.81‰与1.74‰。（2）孟氏螺蛳在湖泊水体环境中生长时，壳体δ13Cshell记录了湖泊水体DIC的δ13CDIC变化特征，揭示出杞麓湖水体DIC主要受大气交换和湖泊中生物系统共同影响，其δ13CDIC在季节尺度变化不显著。（3）杞麓湖湖泊中大量水生藻类的死亡引起的有机质分解将导致湖泊水体δ13CDIC发生显著偏负变化，据此推断壳体δ13Cshell记录的偏负变化与云南2013年大旱期事件吻合，揭示出孟氏螺蛳壳体δ13Cshell具有记录湖泊生态系统自身重大变化的潜力。孟氏螺蛳古螺壳在滇中湖泊广泛分布，基于本文研究结果将有利于基于地层中的壳体识别地质历史时段滇中湖泊水体DIC特征及其湖泊生态系统的变化。 |
| 关键词: 杞麓湖 孟氏螺蛳 碳同位素 水体溶解无机碳 |
| DOI： |
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| 基金项目:(41977390)和云南省高原地理过程与环境变化重点实验开放(PGPEC201801)联合资助。**通讯作者 雷国良 E-mail: leiguoliang@fjnu.edu.cn |
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| Changes in dissolved inorganic carbon recorded by carbon isotopes of the living Anularya mansuyi shells in Qilu lake |
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jianggeping1, leiguoliang1, zhuyun, Zhangwenxiang2, yuyuan, xulihong, duyaohua, liquancong, sunwanting
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1.Fujian Normal University;2.Yunnan Provincial Key Laboratory of Geographical Process and Environmental Change on the Plateau, Yunnan Normal University
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| Abstract: |
| The carbon isotope of gastropod shell carbonates in lakes is directly correlated with dissolved inorganic carbon (DIC), providing vital signals for the regional carbon cycle in lakes. Lakes are widely distributed in the central Yunnan region, and little is known about the DIC characteristics of these lakes. Anularya mansuyi shells are a unique genus of the lakes in central Yunnan province. Here, two living Anularya mansuyi shells (QLH-A and QLH-B) were collected from Qilu Lake and their carbon isotope composition of shell carbonate (δ13Cshell), longitudinally along their growth span were studied to research dissolved inorganic carbon shifts in Qilu Lake’s waters. The research results showed that: (1) The δ13Cshell values can be used to identify the Anularya mansuyi shells’ growth in the mother"s internal environment, the average values of δ13Cshell are -3.78‰ and -5.55‰, with ranges of variation of 2.07‰ and 3.03‰, respectively. In lake water environment, the average δ13Cshell values of the shells are -2.90‰ and -3.28‰, with ranges of variation of 1.81‰ and 1.74‰, respectively. (2) During the period when Anularya mansuyi grows in the lake water, the δ13Cshell of shells record the δ13CDIC characteristics of lake water DIC, and indicating that the DIC of the Qilu Lake water body is mainly affected by atmospheric exchange and the biological system. The δ13CDIC values of DIC have showed no significant seasonal variation in Qilu Lake. (3) Followed algal bloom, the organic matter decomposition caused by the death of aquatic algae in lake system will lead to negative δ13CDIC. Basing δ13CDIC records of 2012~2013 , the negative δ13Cshell during the second half of 2013 is consistent with the Yunnan Drought Event in 2013 and reveals the δ13Cshell of the Anularya mansuyi shells have the potential to record significant changes in the lake ecosystem. The fossil shells of Anularya mansuyi are widely distributed around lakes in central Yunnan, and these fossil shells can be used as potential documents to identify the DIC characteristics of water bodies and changes in lake ecosystems during geological historical periods about lake bodies in central Yunnan Province. |
| Key words: Qilu Lake Anularya mansuyi Carbon isotope Dissolved Inorganic Carbon |
