Wang Wenwen, Zhao Li, Li Wei, Chen Junyi, Wang Shuhang
MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing, 102206, China.
National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
Environ Sci Pollut Res Int. 2023 Feb;30(10):26778-26790. doi: 10.1007/s11356-022-24097-z. Epub 2022 Nov 12.
Lake organic matter is one of the important forms of terrestrial carbon, and its sedimentary evolution is affected by many factors such as climate and sources. However, few studies have been conducted on the feedback mechanism of the sedimentary evolution of organic matter to climate change in cold and arid lakes. Historical variations and compositions of sources of the sediment organic matter (SOM) of Hulun Lake, a typical lake in the cold and arid region of China, were studied by multiple methods. The interactions and fee7dback mechanisms between the sedimentary evolution of SOM and climate change, and compositions of SOM source change, were also discussed. Overall, the characteristic indexes of the SOM, including total organic carbon (TOC), carbon stable isotope (δC), carbon to nitrogen ratio (C/N), and fluorescence intensity (FI) of the protein-like component in water extractable organic matter (WEOM), showed obvious and uniform characteristics of periodical changes. The indexes were relatively stable before 1920, and fluctuated from 1920 to 1979. Since the 1980s, values of TOC, δC, and FI of the protein-like component in WEOM has increased, while C/N decreased. The absolute dominant contribution of terrestrial source to the SOM had changed, and the relative average contribution rate of autochthonous source increased from 17.6% before 1920 to 36.9% after 2000. The increase of temperature, strong evaporation concentration effect, and change of compositions of SOM sources are the important driving factors of the sedimentary evolution of organic matter in Hulun Lake.
湖泊有机质是陆地碳的重要存在形式之一，其沉积演化受气候和物源等多种因素影响。然而，针对寒冷干旱湖泊中有机质沉积演化对气候变化的反馈机制的研究较少。运用多种方法对中国寒冷干旱地区典型湖泊呼伦湖沉积物有机质（SOM）的历史变化及物源组成进行了研究。同时，还探讨了SOM沉积演化与气候变化以及SOM源组成变化之间的相互作用和反馈机制。总体而言，SOM的特征指标，包括总有机碳（TOC）、碳稳定同位素（δC）、碳氮比（C/N）以及水可提取有机质（WEOM）中类蛋白组分的荧光强度（FI），呈现出明显且一致的周期性变化特征。这些指标在1920年之前相对稳定，1920年至1979年期间波动变化。自20世纪80年代以来，WEOM中类蛋白组分的TOC、δC和FI值升高，而C/N降低。陆地源对SOM的绝对主导贡献发生了变化，自生源的相对平均贡献率从1920年之前的17.6%增加到2000年之后的36.9%。温度升高、强烈的蒸发浓缩效应以及SOM源组成的变化是呼伦湖有机质沉积演化的重要驱动因素。
