| 地下河出口河流水化学昼夜动态变化——生物地球化学过程的控制 |
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| 关键词:karst diurnal aqueous chemistry biogeochemistry Guangcun of Guangxi |
| 基金项目:国土资源部公益性科研行业专项(编号: 201111022, 201311148);广西科学技术计划项目(编号: 桂科能1298018-6);中国地质调查局地质调查项目(编号: 12120113014200);国家自然科学基金(编号: 41202185);联合国教科文组织/国际地科联国际地学计划项目(编号: IGCP 598) |
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| Diel Aqueous Chemical Cycling in a Typical Karst Spring-fed Stream: Controls of Biogeochemical Processes |
| The study of diel variations can help to reveal biogeochemical processes that occur relatively rapidly in natural waters and also the main and important controlling factors that influence the changes of aqueous chemistry. Three-day monitoring with high resolution data logger and high frequency sampling with 1-hour interval were conducted in a typical karst spring-fed stream with abundant aquatic vegetation. Daily cycling of hydrochemistry and its changes along the stream flow were discussed and the influence of biogeochemical processes on hydrochemistry was analyzed. The results show that the changes in aqueous chemistry are closely associated with biogeochemical processes and featured as diel cycling. Concentrations of Ca2+ and DIC decrease during the daytime with an amplitude of 22.4%, which reflects the controls of photosynthesis of aquatic plants and suggests that the stream loses Ca2+, DIC and nutrients with downstream distance, but changes of various components along the stream flow are quite different. NO3- concentration also tends to decrease along the stream flow, which is consistent with plant assimilation and exhibits a slightly daytime increasing and nighttime decreasing cycling in a 24-hour time scale. The latter may be caused by nitrification in such a nutrient-rich stream. Data of DOC and TOC collected at hourly interval change quickly but still have a daytime increase and nighttime decrease cycling, with daily increases of as high as 100%. These diel DOC and TOC cycles are likely caused by metabolic processes. The study of diel hydrochemical cycling and biogeochemical processes in karst spring-fed streams will improve understanding of carbon conversion rate between DIC and DOC in karst aquatic environments and thus lead to better estimation of karst carbon sink. |
| ZHANG Cheng,WANG Jin-liang,PU Jun-bing.2015.Diel Aqueous Chemical Cycling in a Typical Karst Spring-fed Stream: Controls of Biogeochemical Processes[J].Acta Geoscientica Sinica,36(2):197-203. |
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