| 不同水期洞庭湖水体中磷分布特征及影响因素 |
| 摘要点击 2352 全文点击 813 投稿时间：2018-09-17 修订日期：2018-11-22 |
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| 中文关键词 洞庭湖 不同水期 各形态磷 季节性变化 悬浮颗粒 影响因素 |
| 英文关键词 Dongting Lake different water periods various forms of phosphorus seasonal variation suspended particles influencing factors |
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| 中文摘要 |
| 为研究不同水期洞庭湖水体中磷的分布特征及影响因素，分别于2016年1~12月对洞庭湖湖区及其入湖河流共18个代表性监测断面采集水样，分析了样品中各形态磷质量浓度.结果表明，总体上，洞庭湖水体中总磷（TP）、溶解性总磷（DTP）和磷酸盐（DPO）均表现为平水期 > 枯水期 > 丰水期，具有明显的季节性变化特征.空间分布上，枯、平水期湖区水体磷质量浓度由西向东增加，丰水期由西向东减少.时间分布上，东、西洞庭湖和出湖口水体中各形态磷质量浓度季节性分布差异明显，西洞庭湖表现为丰水期大于枯、平水期，东洞庭湖和出湖口表现为枯、平水期大于丰水期.形态组成上，与三峡水库蓄水前不同，洞庭湖湖区及其入湖河流水体中磷以溶解态为主，DTP是TP的主要形态，DPO是DTP的主要形态.洞庭湖水体中悬浮颗粒（SS）和磷的分布有一定的协同性，各水期SS和磷质量浓度呈显著或极显著相关关系，因此认为SS是洞庭湖水体中磷季节性变化的重要影响因素.另外，南嘴断面、大小西湖断面、东洞庭湖湖区等区域受周边人类活动影响造成的水体磷污染较重，应引起高度重视. |
| 英文摘要 |
| To study the distribution characteristics and influencing factors of phosphorus in the Dongting Lake at different water periods, water samples were collected from 18 representative monitoring sections located in the Dongting Lake and its upper rivers from January to December 2016. Various forms of phosphorus concentration in the samples were analyzed. The results showed that, overall, the average concentrations (range) of total phosphorus (TP), total dissolved phosphorus (DTP), and phosphate (DPO) in the Dongting Lake were 0.085 mg·L-1(0.030-0.176 mg·L-1), 0.062 mg·L-1(0.017-0.151 mg·L-1), and 0.053 mg·L-1(0.007-0.144 mg·L-1), respectively. These forms of phosphorus concentrations were all characterized by the intermediate season (IS) > the dry season (DS) > the wet season (WS), with obvious seasonal variation characteristics. In the spatial distribution, the phosphorus concentration increased from west to east in DS and IS and decreased from the west to east in WS. In terms of time distribution, various forms of phosphorus were characterized by obvious seasonal distribution in the east, west, and outlet of the Dongting Lake. The phosphorus concentration in WS was higher than that in DS and IS in the West Dongting Lake. However, the concentration was higher during DS and IS than that in WS for the east and outlet of lake. Various forms of phosphorus concentrations in the west were highest in the Dongting Lake during WS, while those in the outlet and east were relatively highest in DS and IS. Therefore, the phosphorus pollution in the West Dongting Lake should receive more attention during WS, and the pollution in the east and outlet requires higher attention during DS and IS. In terms of form composition, according to the monthly data of the sections, the values of ρ(TPO)/ρ(TP) and ρ(DPO)/ρ(TPO) were mainly above 60% in the water body of the Dongting Lake and its upper rivers. DTP was the main form of TP, and DPO was the main form of DTP. It indicated that the phosphorus in the Dongting Lake and its upper rivers was mainly soluble, which is different from that before the impoundment of the Three Gorges Reservoir. The spatio-temporal distribution of suspended particles (SS) and phosphorus in the Dongting Lake had a certain synergistic effect. The concentration of SS and phosphorus in each water period showed a significant or extremely significant correlation. Therefore, SS was considered as an important factor affecting the seasonal variation of phosphorus in the Dongting Lake. In this study, it was concluded that the Nanzui section, the Daxiaoxihu section, and the East Dongting Lake area were clearly affected by surrounding human activities, respectively including domestic, agricultural, and sand mining sources of phosphorus pollution. The water in the West Dongting Lake has even been affected by mild and moderate eutrophication in 2016. These phenomena should be paid more attention. |
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