河流“呼吸”作用及其性质研究的综述及展望

A Review and Perspectives of the Research on Riverine "Breath" and Its Features

河流是联系地球系统各大碳库的纽带,其碳行为是解析地球系统碳循环的重要环节。作为流域系统的重要"呼吸"窗口,河流"呼吸"作用的特征依赖于河道水-气界面体系中各种理化性状和反应条件以及流域系统内的各种自然环境特征,反映了流域有机质在河道系统中贮存、分解、转化规律。影响河流"呼吸"作用的直接因子有河道水体的温度、总碱度、pH值及其水动力条件和周围大气的风速、温度、湿度和大气的CO2分压等,而上述直接因子与流域的地理位置、形状、海拔高度、下垫面状况等相关。河流"呼吸"作用由于受上述影响因子的综合作用表现出很强的地域性和季节性。河流"呼吸"作用研究的发展方向应致力于在解决"大气碳源汇平衡"和"失踪的陆源碳"两个科学问题上有所作为。

River is a joint that connects carbon pools in the Earth system. Riverine carbon behavior is an important link to analyze the carbon cycle of the Earth system and the mechanism of the biogeochemistry cycle. Riverine ＂breath＂, as an important ＂breath mouth＂ of the basin system, reflects the stockpile, decomposition and transformation law of the riverine organic matter in the basin, which depends on the physical-chemical characteristics and the reaction conditions in the water-atmosphere interface system. The mechanism of the riverine ＂breath＂ is discussed in the paper. It is considered that the direct factors to influence the ＂breath＂ include the temperature, total alkalinity and pH of riverine water and the riverine hydrodynamic condition, as well as the wind speed, temperature, humidity and pCO2 of the ambient atmosphere; while the indirect factors include the geographical location, shape, altitude and underlying surface of the basin. By the compositive effect of above-mentioned factors, riverine ＂breath＂ takes on distinct regional and seasonal features in the drainage basin. The study of fiver ＂breath＂ should commit itself to settling two scientific problems, one is ＂source and sink balance of atmosphere carbon＂ and the other is ＂missing terrestrial carbon＂, and should set up availability modes to reckon carbon flux of the riverine ＂breath＂ and study its mechanism.