多年冻土区河流溶解性有机碳输出的研究进展  

Export of Dissolved Organic Carbon in Streams Draining Permafrost-Dominated Areas:A Review

作　　者：安志宏 孙自永[3] 胡雅璐[3] 王烁 An Zhihong;Sun Ziyong;Hu Yalu;Wang Shuo(School of Earth and Space Sciences, Peking University, Beijing 100871, China;China Aero Geophysical Survey and Remote Sensing Center for Land and Resources, Beijing 100083, China;School of Environmental Studies, China University of Geosciences（Wuhan）, Wuhan 430074, China)

机构地区：[1]北京大学地球与空间科学学院,北京100871 [2]中国国土资源航空物探遥感中心,北京100083 [3]中国地质大学(武汉)环境学院,武汉430074

出　　处：《地质科技情报》2018年第1期204-211,共8页Geological Science and Technology Information

基　　金：国家自然科学基金项目(91325101)

摘　　要：多年冻土区河流中溶解性有机碳(DOC)的输出对全球碳循环有着重要贡献,是全球气候变化研究的热点。当前研究主要集中在2个方面:多年冻土区河流DOC输出的时空特征及其影响因素;多年冻土区河流DOC输出对气候变暖和冻土退化的响应。研究表明,河流中DOC的浓度、通量、化学组分等主要受流域内水的流动路径、滞留时间及路径上潜在DOC源的特征控制,而多年冻土的分布及其季节性融冻循环对上述因素有显著影响,进而控制多年冻土区河流DOC的输出规律。气候变暖可从3个方面对多年冻土区河流DOC输出产生影响:(1)造成多年冻土退化,使地下水的流动路径变深和滞留时间增长,导致河流的DOC输出量降低;(2)使多年冻土中储存的老有机碳释放,导致河流的DOC输出量增高;(3)改善深部土壤的通气和温度条件,促进土壤微生物活性,进而影响河流DOC的输出量和化学特征。今后,有3个方面的研究需要加强:(1)中、低纬度高海拔冻土区河流DOC的输出规律及其与流域水文过程的关系;(2)小型源头河流DOC输出的对比与控制性试验;(3)冻土区地下水流过程的精细刻画和潜在有机碳源的直接探测。Dissolved organic carbon（DOC）fluxes in streams and rivers draining permafrost-dominated areas contribute significantly to the global carbon cycle,and thus become the research focus of global climate change.Recent researches are mainly centered on patterns and controls of DOC export in streams from permafrost-influenced catchments and their responses to permafrost degradation caused by climate warming.These researches demonstrate that the distribution of permafrost and seasonal frozen ground and the freeze-thaw cycle of active layer significantly influence DOC concentrations,fluxes and compositions in rivers by altering hydrologic flow paths,water residence times and potential DOC sources in the catchment.Global warming may affect stream DOC export from permafrost-dominated areas in contradictory ways.On the one hand,with permafrost thaw and degradation,active layer thickness,depth of subsurface flows and water residence time may increase,and the DOC delivered to the streams and rivers may decline.On the other hand,degradation of permafrost and increases in active layer depths may facilitate the release of old organic carbon to adjacent streams and rivers.In addition,warmer temperatures and improved aeration occurring with the deepening of active layer stimulate microbial activities,potentially influencing DOC fluxes and chemical compositions in streams and rivers.Future research prospects include,（1）patterns and hydrological controls of DOC export in streams draining permafrost-dominated catchments in mid-low latitude,high altitude mountain areas;（2）control studies of stream DOC export from small headwater watersheds where landscape is homogeneous and thus processes and changes are easier to elucidate;（3）more detailed characterization of groundwater flow and access to deep DOC sources in permafrost areas.

关 键 词：多年冻土 溶解性有机碳 水文过程 气候变化 高寒山区 源头河流 

分 类 号：P641.3[天文地球—地质矿产勘探]