| 太湖草藻型湖区磷赋存特征及其环境意义 |
| 摘要点击 3177 全文点击 1061 投稿时间：2019-07-01 修订日期：2019-07-17 |
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| 中文关键词 太湖 藻型湖区 草型湖区 磷赋存形态 分布特征 |
| 英文关键词 Taihu Lake phytoplankton-dominated zone macrophyte-dominated zone phosphorus fractions distribution character |
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| 中文摘要 |
| 研究草藻型湖区上覆水和沉积物磷赋存特征及环境意义有助于明晰磷在沉积物-水界面的迁移转化过程，对于深入理解不同类型湖区的富营养化过程及富营养化湖泊的治理具有重要现实意义.在太湖典型草藻型湖区进行四季多点采样，分析草藻型湖区水体及沉积物中不同磷形态的时空差异，并揭示其环境意义.结果表明：①藻型湖区上覆水中总磷（TP）、溶解性总磷（DTP）、溶解性无机磷（DIP）和颗粒态磷（PP）显著高于草型湖区，时间分布上大都表现出夏秋高于冬春的特点，PP是TP的主要组成部分，占比71.8%~89.6%.叶绿素（Chl-a）浓度与上覆水中磷赋存形态呈相似的时空分布特征.②藻型湖区表层沉积物TP含量为372.38~529.64mg·kg-1，草型湖区为304.29~454.27mg·kg-1，藻型湖区表层沉积物TP含量明显高于草型湖区，冬季沉积物TP含量最高，夏季最低，这与外源污染的输入以及不同环境条件下内源磷在沉积物和上覆水间的迁移转化有关.③沉积物中不同磷赋存形态数量分布由小到大依次均为：NH4Cl-P、Fe-P、Org-P、Res-P、Al-P和Ca-P.表层沉积物Mobile-P（NH4Cl-P+Fe-P+Org-P）在TP中的占比藻型湖区为9.10%~16.93%，略高于草型湖区8.11%~13.50%，Res-P在TP中占比藻型湖区为10.06%~14.97%，草型湖区为11.02%~20.28%.藻型湖区内源磷释放风险大，不利于磷的固定与埋藏.不同类型的湖区富营养化程度明显不同，在磷的释放与埋藏中也表现出不同变化特点.藻型湖区因其较高的内源磷负荷和释放潜力，值得特别关注. |
| 英文摘要 |
| It is of great importance to study the environmental significance of phosphorus fractions in overlying water and sediments of typical phytoplankton-and macrophyte-dominated zones. It will help to clarify the process of phosphorus migration and transformation in the sediment-water interface, and has practical significance for understanding the eutrophication process and its treatment in different regions of Taihu Lake. The investigation was conducted within typical phytoplankton-and macrophyte-dominated zones of Taihu Lake over four seasons to analyze the spatial and temporal differences between phosphorus fractions in water and sediments, and reveal their environmental significance. The results showed that:① Total phosphorus (TP), total soluble phosphorus (DTP), dissolved inorganic phosphorus (DIP), and particulate phosphorus (PP) in the overlying water of phytoplankton-dominated zones were much higher than those in macrophyte-dominated zones. Most of them showed seasonal characteristics, which were higher in summer and autumn than in winter and spring. PP is the main component of TP, accounting for 71.8% to 89.6%. A similar distribution character was found in the content of chlorophyll (Chl-a) compared with phosphorus concentration in overlying water. ② The concentration of TP in the surface sediments of phytoplankton-dominated zones was 372.38-529.64 mg·kg-1, and that in macrophyte-dominated zones was 304.29-454.27 mg·kg-1. In surface sediments, concentrations of TP in phytoplankton-dominated zones were significantly higher than in phytoplankton-dominated zones. The highest TP concentrations appeared in winter, and the lowest in summer. These were owing to the input of exogenous pollution, and the migration and transformation of internal phosphorus between sediments and overlying water under different environmental conditions. ③ The order of the mass fraction of phosphorus in sediments was:NH4Cl-P < Fe-P < Org-P < Res-P < Al-P < Ca-P. Mobile-P=NH4Cl-P+Fe-P+Org-P, accounting for 9.10%-16.93% of TP in phytoplankton-dominated zones, and slightly higher in macrophyte-dominated zones, where it was 8.11%-13.50%. Res-P accounted for 10.06%-14.97% of TP in phytoplankton-dominated zones, and 11.02%-20.28% in macrophyte-dominated zones. The risk of internal phosphorus release in phytoplankton-dominated zones is high, which is not conducive to the fixation and burial of phosphorus. The eutrophication degree of different regions in Taihu Lake is obviously different, and different characteristics of phosphorus release and burial are showed. The phytoplankton-dominated zones deserve special attention because of their high internal phosphorus load and release potential. |
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