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应用生态学报 ›› 2022, Vol. 33 ›› Issue (10): 2635-2643.doi: 10.13287/j.1001-9332.202210.018

• 陆地生态系统固碳与增汇专栏 • 上一篇    下一篇

坝地剖面泥沙有机碳分解特征及其影响因素

王震1, 刘颖1, 杨明义1,2,3*, 张风宝1,2   

  1. 1西北农林科技大学水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室, 陕西杨凌 712100;
    2中国科学院水利部水土保持研究所, 陕西杨凌 712100;
    3中国科学院第四纪科学与全球变化卓越创新中心, 西安 710061
  • 收稿日期:2022-06-09 修回日期:2022-08-10 出版日期:2022-10-15 发布日期:2023-04-15
  • 通讯作者: * E-mail: ymyzly@163.com
  • 作者简介:王震, 男, 1998年生, 硕士研究生。主要从事土壤侵蚀与碳循环研究。E-mail: 2093817542@qq.com
  • 基金资助:
    国家自然科学基金项目(42177340,41877080)

Characteristics and factors influencing organic carbon decomposition in sediment in check dams

WANG Zhen1, LIU Ying1, YANG Ming-yi1,2,3*, ZHANG Feng-bao1,2   

  1. 1State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conversation, Northwest A&F University, Yangling 712100, Shaanxi, China;
    2Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi, China;
    3Chinese Academy of Sciences Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, China
  • Received:2022-06-09 Revised:2022-08-10 Online:2022-10-15 Published:2023-04-15

摘要: 黄土高原地区已建成的5.6万余座淤地坝累计拦截有机碳0.95 Pg,是陆地生态系统重要的碳汇,但是目前对其分解机制仍知之甚少,难以量化其在陆地碳循环中的作用。本研究通过模拟原始沉积条件下的泥沙环境(缺氧条件)进行矿化培养,并比较假定泥沙暴露在有氧情况下的有机碳分解速率,探究有机碳分解速率的影响因素。结果表明: 坝地泥沙在原始沉积条件和暴露在有氧条件下有机碳分解速率均值分别为(6.47±4.06)和(56.66±17.78) mg C·kg-1·d-1,坝地泥沙在埋藏条件下有机碳分解速率仅为被暴露在有氧条件下的11.4%,表明埋藏显著降低了有机碳分解速率。在缺氧条件下泥沙化学性质比有机碳分解相关微生物对泥沙有机碳分解速率的影响更大;在有氧条件下则表现为有机碳分解相关微生物对泥沙有机碳分解速率的影响更显著;泥沙物理性质对缺氧和有氧条件下泥沙有机碳分解速率的影响均较小。自然情况下,淤地坝表现为碳汇,但当发生溃坝时,原本在沉积缺氧条件下储存的泥沙有机碳会迅速暴露在空气中,有机碳分解速率显著提高,表现为碳源。

关键词: 淤地坝, 氧气条件, 微生物, 有机碳分解速率

Abstract: More than 56000 check dams have been built in the Loess Plateau, which capture around 0.95 Pg of organic carbon and act as an important carbon sink. However, the decomposition mechanism of organic carbon in the sediment in these dams is still poorly understood, and thus it is difficult to quantify their role in terrestrial carbon cycling. In this study, the mineralization culture was used as a simulated environment for the natural sediment environment. With the observations in the simulated environment, the decomposition rates of sediment organic carbon (SOC) were compared under different conditions to investigate the factors influencing the decomposition rate of SOC. The results showed that the average SOC decomposition rate of sediment under anoxic and aerobic conditions was (6.47±4.06) and (56.66±17.78) mg C·kg-1·d-1, respectively. The decomposition rate of SOC in dam sedi-ment under burial conditions was only 11.4% of that under the assumed aerobic condition, indicating that burial condition significantly reduced SOC decomposition. Under anoxic conditions, chemical compositions in the sediment had a greater effect on the decomposition rate of SOC than the microorga-nisms. In contrast, the effect of microorganisms on the decomposition rate of SOC was more significant under aerobic conditions. The physical properties of sediment had little effect on the decomposition rate of SOC under both anoxic and aerobic conditions. Under natural conditions, the siltation dam acted as a carbon sink. When the dam breaks, SOC stored in the sedimentary anoxic condition would be quickly exposed to the air, followed by a significant increase in the decomposition rate, and thus acting as a carbon source.

Key words: check dam, oxygen condition, microorganism, decomposition rate of organic carbon