典型湖区有色可溶性有机物来源、组成和转化的过程与机制

有色可溶性有机物（CDOM）是水体中非常重要的光学活性物质并且富含丰富的碳氮磷生源要素，其来源组成复杂、生态环境效应多样，对区域及全球碳、氮、磷的转化和循环，水生生态系统结构和功能以及气候变化都会产生巨大影响。本项目聚焦CDOM来源、组成和转化的过程与机制及其环境效应，选择CDOM来源组成和循环转化差异明显的云贵高原和东部平原2个典型湖区，开展大范围不同季节的CDOM野外调查和样品采集，以及CDOM降解和转化的野外原位和室内受控实验，综合运用光谱吸收、三维荧光、稳定同位素和超高分辨率质谱等技术方法，定量表征我国典型湖区CDOM丰度的时空格局、区域分异特征及主要影响因素；综合解析和辨识CDOM来源、物质组成和分子结构；深入揭示不同来源和组成CDOM的光降解和微生物降解机制；定量评估CDOM光衰减、温室气体排放和营养盐再生的环境效应，服务于CDOM表征与监测，来源与归趋以及全球碳循环研究。

Chromophoric dissolved organic matter (CDOM) is an important optically active substance in aquatic ecosystems and affects the attenuation of ultraviolet and photosynthetically active radiation. Meanwhile, CDOM plays an important role in the biogeochemical cycling of carbon, nitrogen and phosphorus in natural ecosystems. The sources and composition of CDOM are very complex and CDOM has a multi ecological and environmental effects. In detail, CDOM plays a vital important role in regional and global carbon and nutrient cycling, aquatic ecosystem productivity, ecosystem structure and functions. This project focuses on the processes, driving mechanisms and environmental effects of CDOM sources, compositions and transformations. Field investigation and sample collection of CDOM in a large spatial scale from the lakes of Yungui Plateau and Eastern Plains of different seasons, and in situ and indoor controlled experiments of CDOM degradation and transformation will be carried out. Combining CDOM spectral absorption, three-dimensional fluorescence, stable isotopes and ultrahigh resolution mass spectrometry, this project is aimed to: 1)quantitatively characterize the spatial and temporal pattern, regional differentiation and main influencing factors of the abundance of CDOM; 2)comprehensively analyze and identify CDOM sources, composition and molecular structures; 3) deeply reveal the processes and mechanisms of photodegradation and microbial degradation of different sources and composition of CDOM; 4)quantitatively evaluating the ecological and environmental effects of CDOM light attenuation, greenhouse gas emission and nutrients regeneration. The study results will be helpful to to improve our knowledge of the characterization, monitoring, sources and fates of CDOM in inland waters, and the global carbon cycle.