| 库湾营养盐循环对三峡库区营养盐输运的影响:以草堂河为例 |
| 摘要点击 2403 全文点击 832 投稿时间：2016-01-29 修订日期：2016-03-24 |
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| 中文关键词 三峡库区 草堂河 营养盐 分布特征 来源 |
| 英文关键词 Three Gorge Reservoirs (TGR) Caotang tributary nutrients distribution characteristics source |
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| 中文摘要 |
| 三峡水库蓄水后，库区众多支流下游形成库湾回水区，这些库湾回水区是库区水环境调整最为活跃的地区. 为了探究支流库湾对于库区生源要素循环及物质通量的作用和意义，于2012年8月~2013年7月对草堂河库湾、相邻干流、支流上游水体中溶解态无机氮（DIN）、溶解态无机磷（DIP）、溶解态硅酸盐（DSi）的时空分布进行逐月现场观测. 结果表明，草堂河库湾回水区营养盐的浓度与库区干流相近，二者的月变化趋势也高度一致. 干流输入是库湾DIN、DIP、DSi的主要来源. 草堂河库湾与干流连通性很好，干支流水体交换迅速且充分，其影响可到达库湾回水区的末端. 春、夏季，干流输入的营养盐通过表层生产力在库湾截留，秋、冬季库湾中的营养盐释放并输送到干流. 营养盐在库湾的这种循环过程，在一定程度上改变了库区干流不同季节营养盐输送的节律. 库区支流库湾众多，其对干流物质通量的季节调配作用不容忽视. |
| 英文摘要 |
| Backwater regions have been formed in the downstream of tributaries since the Three Gorge Reservoir (TGR) was impounded, as the most influential area to the aquatic environment within the reservoir. In order to study the effects and significance of the backwater regions on the nutrient cycling and substance fluxes, dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), dissolved silicon (DSi) were monitored in situ in Caotang tributary backwater region, the adjacent mainstream and Caotang tributaries' upstream every month from August 2012 to July 2013. The results showed that the concentrations of DIN, DIP and DSi in Caotang tributary backwater region were similar to those in the mainstream, and the monthly variation tendency was very consistent with the mainstream Changjiang. DIN, DIP and DSi in the Caotang tributary were mainly originated from the mainstream. The influence of the mainstream water could extend to the upmost of the backwater region due to the good connection and rapid, sufficient water exchange between mainstream and tributary. Nutrients from the mainstream were retained and consumed by primary producers in the tributary during the growing seasons in spring and summer, while released back to the water during late autumn and winter. Nutrient cycling in the tributary could change the seasonal pattern of nutrient transportation. The mainstream nutrient fluxes could receive significant seasonal modification from the large numbers (more than 40) of tributaries within the TGR domain. |
