桂林潮田河水溶解无机碳昼夜变化与通量 |
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关键词:dissolved inorganic carbon aquatic photosynthesis diurnal cycling flux Chaotian river of Guilin |
基金项目:中国地质科学院基本科研业务费项目(编号: YYWF201639; JYYWF20182002);科技部援外项目(编号: KY201802009);广西科技计划项目(编号: 桂科AD17129047);中国科学院国际合作局国际伙伴计划项目(编号: 132852KYSB20170029-01) |
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摘要: |
Day and Night Variations of Dissolved Inorganic Carbon and Flux in Chaotian River, Guilin, Guangxi |
Small mountain river systems are suitable sites for biogeochemical process studies because of their relatively small catchments, shorter response time and easier identification of anthropogenic activities on their hydrochemistry and biogeochemistry. Taking Chaotian River in Guilin of Guangxi as an example, the authors studied day and night variations of hydrochemistry, inorganic carbon removal and their biogeochemical control mechanism by high resolution monitoring and high frequency sampling. The results show that pH values, dissolved oxygen, specific conductivity, and concentrations of bicarbonate and calcium present remarkable diurnal cycling resulting from aquatic photosynthesis and calcium precipitation and, furthermore, the diurnal amplitudes of all those parameters are close related to riverbed substrate and aquatic plant species. The daytime falling ranges of calcium and bicarbonate concentrations are 12% and 11% respectively at Niaolingqiao monitoring site with well developed algae-covered gravel substrate and 10.6% and 8.9% respectively at Lianghegou monitoring site with muddy riverbed and abundant submerged plants. Dissolved oxygen and pH values are mainly controlled by local in-stream processes, namely aquatic vegetation photosynthesis, whereas specific conductivity could be affected obviously by upstream transmission signals. The timelag of specific conductivity is supposed to be similar to the advection transit time between the two sites. Calcium precipitation and dissolved inorganic carbon removal caused by aquatic photosynthesis at monitoring section were estimated to be 302 kg/d and 997 kg/d, i.e., 188.75 g/m/d and 623.13 g/m/d, respectively. The values are 4 to 5 times higher than the results from representative spring-fed streams in southwest China karst region, implying inorganic carbon is converting to organic carbon by aquatic photosynthesis in small karst rivers. It acts as a real meaning natural carbon sink process to waterbody carbon flux. |
ZHANG Cheng,WANG Jin-liang,XIAO Qiong,GUO Yong-li,MIAO Ying.2021.Day and Night Variations of Dissolved Inorganic Carbon and Flux in Chaotian River, Guilin, Guangxi[J].Acta Geoscientica Sinica,42(4):555-564. |
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