| 桂林潮田河水溶解无机碳昼夜变化与通量 |
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| 引用本文： | 章程,汪进良,肖琼,郭永丽,苗迎.桂林潮田河水溶解无机碳昼夜变化与通量[J].地球学报,2021,42(4):555-564. |
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| 作者姓名： | 章程 汪进良 肖琼 郭永丽 苗迎 |
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| 作者单位： | 中国地质科学院岩溶地质研究所, 自然资源部/广西岩溶动力学重点实验室 |
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| 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： | 小型山区河流系统具有流域面积小、响应时间短、人类活动的水化学影响易识别等特点,是研究生物地球化学过程的理想场所.本文以桂林潮田河为例,通过高分辨率监测与高频取样,研究水化学昼夜动态变化,无机碳移除及其生物地球化学控制机理.受水生光合作用与钙沉积作用的控制,河水pH、DO、SpC、HCO–3和Ca2+离子产生显著的昼夜动态变化,这些水化学指标昼夜变幅大小又与河床基质和水生植物类型有关.砾石类河床藻类发育的鸟岭桥河段Ca2+和HCO3-含量白天下降幅度平均值分别为12％和11％,泥质类河床沉水植物发育的两河沟河段为10.6％和8.9％.DO浓度与pH值主要受局地河流内部过程控制,即水生植物或藻类光合作用控制,而电导率受上游传输影响较大,滞后时间与两点之间信号平流传输时间相关.监测河段水体因光合作用产生的钙沉降与溶解无机碳移除量分别为302 kg/d和997 kg/d,即188.75 g/m/d和623.13 g/m/d,是西南亚热带典型地下河出口河流的4～5倍,小型岩溶河流沿流程发生的无机碳向有机碳转化,对水体碳通量而言,是真正意义上的自然碳汇过程.
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| 关 键 词： | 溶解无机碳 水生光合作用 昼夜变化 通量 桂林潮田河 |
Day and Night Variations of Dissolved Inorganic Carbon and Flux in Chaotian River, Guilin, Guangxi |
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| ZHANG Cheng,WANG Jin-liang,XIAO Qiong,GUO Yong-li,MIAO Ying.Day and Night Variations of Dissolved Inorganic Carbon and Flux in Chaotian River, Guilin, Guangxi[J].Acta Geoscientia Sinica,2021,42(4):555-564. |
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| Authors: | ZHANG Cheng WANG Jin-liang XIAO Qiong GUO Yong-li MIAO Ying |
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| Institution: | Karst Dynamics Key Laboratory of Ministry of Natural Resources/Guangxi Zhuang Autonomous Region,Institute of Karst Geology, Chinese Academy of Geological Sciences |
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| Abstract: | 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. |
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| Keywords: | dissolved inorganic carbon aquatic photosynthesis diurnal cycling flux Chaotian river of Guilin |
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