| 异养细菌作用下岩溶水体惰性有机碳变化及其环境影响因素分析 |
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| 关键词:RDOC heterotrophic bacteria biological effect hydrodynamic condition karst water |
| 基金项目:广西自然科学基金杰出青年基金项目“岩溶地球化学”(编号: 2015GXNSFGA139010);成都工业学院校级项目(编号: 2021ZR023) |
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| Variation of Recalcitrant Dissolved Organic Carbon in Karst Water under the Influence of Heterotrophic Bacteria and Its Environmental Controlling Factors |
| Recalcitrant dissolved organic carbon is difficult to be biodegraded and constitute long-term carbon sequestration. The fertilization effect of karst water on phytoplankton increased the biomass, which theoretically provides sufficient organic substrates for heterotrophic bacteria promoting its metabolism, which could generate more RDOC. Samples were taken along the Liujiang River at Guangxi in July and September 2016. The δ14C method was used to measure the primary productivity of bacteria; the fluorescent real-time quantitative PCR method was used to measure the bacteria and AAPB abundance, and the in-situ microbial cultivation method was used to determine the RDOC concentration in the basin. Based on the results, the RDOC measured from 1.46~2.66 mg·L–1, with an average of 1.85 mg·L–1, accounting for 48.16%~92.61% of DOC which showed a significant seasonal and spatial variation. With the rise in water temperature and decreased turbidity, the plankton primary productivity increased during the normal season providing sufficient organic carbon for heterotrophic bacteria. The increased bacterial abundance and its primary productivity generated more RDOC than that in the wet season. However, the spatial variation of RDOC presented different responding mechanisms, which were mainly controlled by hydrodynamics. The slow flow rate of the site behind the reservoir dam was conducive to the growth and metabolism of aquatic organisms. The concentration of chlorophyll a, bacterial abundance, and both primary productivity of plankton and bacteria had all increased significantly at the site behind the reservoir dam, but the RDOC concentration decreased because the slow flow rate also made it easier for organic matter and biopolymers to settle, reducing the DOC concentration in water. The results indicated that biological effect, carbon sources, and specific hydrophysical/hydrochemical properties were the main impacting factors of RDOC. The heterotrophic bacteria were the main contributor to RDOC in the basin, and the endogenous organic carbon produced by planktons promoted the production of RDOC. |
| HE Ruo-xue,LI Qiang,YU Shi,SUN Ping-an.2022.Variation of Recalcitrant Dissolved Organic Carbon in Karst Water under the Influence of Heterotrophic Bacteria and Its Environmental Controlling Factors[J].Acta Geoscientica Sinica,43(4):438-448. |
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