Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, People's Republic of China.
The University of Chinese Academy of Sciences, Beijing, 10049, China.
Environ Sci Pollut Res Int. 2019 May;26(14):14116-14127. doi: 10.1007/s11356-019-04568-6. Epub 2019 Mar 11.
Carbon (C) in riverine ecosystems play an important role in regulating terrestrial carbon reservoir to the oceans and atmosphere, thus, understanding C dynamics in riverine ecosystem are essential for understanding global carbon cycle. Here, we investigated the seasonal and spatial variations in concentrations of dissolved inorganic carbon (DIC), particulate organic carbon (POC), and their carbon isotopic signatures (i.e., δC-DIC, δC-POC) in the tributaries and main channel of the upper Han River, China. Dissolved organic carbon (DOC), total suspended solid (TSS), and other physicochemical parameters including water temperature, pH, dissolved oxygen (DO), and electrical conductivity (EC) were also measured. We found that POC concentration was significantly higher in wet season and in main channel, and DIC concentration did not show significant spatiotemporal variability. DIC and POC were positively related to DOC, and they were also positively correlated with water temperature and TSS, respectively. δC-DIC and δC-POC had significant seasonal and spatial variations, and δC-DIC was significantly higher in dry season and δC-POC was significantly higher in the tributaries and in dry season. δC-DIC was negatively related to the TSS concentration, while δC-POC was negatively correlated with water temperature, DIC, and DOC concentrations. Our results suggest that water temperature and TSS are the primary factors in regulating C concentrations, and their stable isotopic signatures are primarily affected by aquatic photosynthesis and riverine respiration in the upper Han River, China.
河流生态系统中的碳在调节陆地碳库向海洋和大气的输送方面起着重要作用，因此，了解河流生态系统中的碳动态对于理解全球碳循环至关重要。在这里，我们调查了中国上汉江支流和干流中溶解无机碳（DIC）、颗粒有机碳（POC）及其碳同位素特征（即δC-DIC、δC-POC）的季节性和空间变化。还测量了溶解有机碳（DOC）、总悬浮固体（TSS）和其他理化参数，包括水温和 pH 值、溶解氧（DO）和电导率（EC）。我们发现，POC 浓度在雨季和干流中显著较高，而 DIC 浓度没有表现出显著的时空变化。DIC 和 POC 与 DOC 呈正相关，它们分别与水温 TSS 呈正相关。δC-DIC 和 δC-POC 具有显著的季节性和空间变化，δC-DIC 在旱季较高，δC-POC 在支流和旱季较高。δC-DIC 与 TSS 浓度呈负相关，而 δC-POC 与水温、DIC 和 DOC 浓度呈负相关。我们的研究结果表明，水温和 TSS 是调节碳浓度的主要因素，其稳定同位素特征主要受到中国上汉江中水生光合作用和河流呼吸的影响。
