贺海波,
李祥忠^,
云南大学, 云南省地球系统科学重点实验室, 云南 昆明 650500

基金项目: 国家自然科学基金项目(批准号：42007296)、云南省****基金项目(批准号：202001AV070012)和云南省基础研究计划青年项目(批准号：202001BB050023)共同资助


详细信息

作者简介: 贺海波, 男, 31岁, 博士, 环境地球化学专业, E-mail: hehaibo@ynu.edu.cn

通讯作者: 李祥忠, E-mail: xzhli04@163.com

中图分类号: P593;P941.78

收稿日期:2020-12-20
修回日期:2021-04-08
刊出日期:2021-07-30

Study on the utilization efficiency of HCO₃^- by aquatic plants and the buried flux of autochthonous organic carbon in Fuxian Lake

HE Haibo,
LI Xiangzhong^,
Yunnan Key Laboratory of Earth System Science, Yunnan University, Kunming 650500, Yunnan



More Information

Corresponding author: LI Xiangzhong,E-mail:xzhli04@163.com

MSC: P593;P941.78

--> Received Date: 20 December 2020
Revised Date: 08 April 2021
Publish Date: 30 July 2021


摘要
摘要:因可能是全球"遗失碳汇"的重要组分，耦合生物碳泵效应的碳酸盐风化碳汇日益受到学界关注，并且其对不同时间尺度上的气候变化都可能产生重要影响。由碳酸盐风化产生的HCO₃^-能否形成稳定的碳汇尚缺乏足够论证，厘清这一问题的关键在于如何有效评估水生植物固定HCO₃^-的能力，尤其是植物残体进入沉积物后的实际碳固定量。本文基于已发表的抚仙湖数据，利用碳同位素端元模型估算了抚仙湖水生植物光合固定HCO₃^-碳量，发现无机碳源中约有57%是以HCO₃^-的形式被水生植物光合固定下来，碳汇通量达24.76 tC/(km²·a)。而可能由于微生物分解等作用，抚仙湖现代沉积物中真正被埋藏下来的内源有机碳沉积通量，即耦合生物碳泵效应的碳酸盐风化碳汇通量仅为9.2~16.4 tC/(km²·a)，这大致相当于水生植物所固定HCO₃^-的一半。尽管如此，水生植物的光合作用和碳酸盐风化耦合作用仍表现出巨大的碳汇潜力。因此，在未来的全球碳循环和气候变化模型中需考虑碳酸盐风化碳汇的影响。
关键词: 碳酸盐风化碳汇/
生物碳泵效应/
水生植物/
HCO₃^-/
有机碳埋藏

Abstract:The carbon fixed by the coupled carbonate weathering with aquatic photosynthesis mechanism may account for a significant portion of global 'missing sink'. This mechanism is therefore playing an underestimated role in climate changes on various timescales, and is attracting increasing attention from the climate community. However, how much carbon can be fixed through this mechanism is still debated, in particular, whether carbonate rock dissolution derived bicarbonates(HCO₃^-) can form a stable carbon sink is still not certain. To better quantify the carbon sink by the coupled carbonate weathering with aquatic photosynthesis mechanism, we need to evaluate the ability of aquatic plants in HCO₃^- fixation, especially the effective carbon sequestration resulting from plant residues burial. Here, based on published data, we calculated carbon budget within the characteristic Fuxian Lake catchment(24°17'~24°37'N, 102°49'~102°57'E) utilizing the carbon isotope model. We have found that ca. 57% of HCO₃^- is utilized by aquatic plants, and the carbon sink flux within the catchment reaches ca. 24.76tC/(km²·a). However, nearly half of the carbon sink flux is compensated by microbial decomposition, and resulted burial flux of autochthonous organic carbon in the modern sediments, i.e. the carbon sink by the coupled carbonate weathering with aquatic photosynthesis mechanism, is reduced to ca. 9.2~16.4tC/(km²·a). Nevertheless, our modeled results still show the great potential of the combination of photosynthesis and carbonate weathering in carbon sequestration. Therefore, atmospheric CO₂ uptake by carbonate weathering should be included in the global carbon cycle and climate change model.
Key words:carbon sink by carbonate weathering/
biological carbon pump effect/
aquatic plants/
HCO₃^-/
organic carbon burial



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