三峡坝区干流及香溪河库湾水体秋季二氧化碳分压

于2009年9月对三峡水库坝区干流以及坝区主要库湾-香溪河流域水体中溶解CO2分压(pCO2)进行了走航观测。结果表明:秋季香溪河表层pCO2为150～240μatm,三峡水库坝区干流表层pCO2为920～1140μatm;在干、支流交汇处的水柱剖面上,表层水体pCO2最低为368μatm,随着水深的增加,pCO2急剧增大,在10m达到最大值1300μatm,10m后保持不变;通过计算,香溪河和三峡水库坝区干流河道的CO2释放通量分别为-4.74±1.15和(83.7±14.1)mmol.m-2.d-1。香溪河表现为CO2的"汇",而三峡水库坝区干流表现为CO2的"源"。在评价水库建设对周边区域CO2通量影响时,不仅要考虑局部流域,更需要对整个研究地区进行综合考察。

Partial pressure of water body dissolved carbon dioxide in mainstream and Xiangxi bay of Three Gorges Reservoir area in autumn

In September 2009,a cruise investigation was conducted to study the partial pressure of water body dissolved carbon dioxide(pCO2) in the mainstream and Xiangxi River of the Three Gorges Reservoir Area in autumn.The pCO2 in the surface water of the mainstream and Xiangxi River was 920-1140 and 150-240 μatm,respectively.At the joint area of mainstream and distributaries,the pCO2 had a minimum of 368 μatm in surface water,and increased markedly with increasing water depth,being the maximum(1300 μatm) at 10 m depth and keeping stable downward.The CO2 flux of the mainstream and Xiangxi River was 83.7±14.1 and-4.74±1.15 mmol·m-2·d-1,respectively,indicating that the mainstream was a sink,while Xiangxi River was a source of CO2.Therefore,when evaluating the influence of reservoir construction on the CO2 flux in reservoir’s surrounding regions,it would be necessary not only considering the local basins,but also investigating the entire study area comprehensively.