太湖水体溶解态磷的时空变化特征

对2010年太湖西岸区北段、湖心北区、贡湖、梅梁湾、竺山湾、西岸区南段、湖心南区、南岸区和湖心区9个研究点位水体中的溶解态总磷(TSP)、溶解态反应磷(SRP)和叶绿素a(Chl-a)进行了长达1年的动态监测,全面分析了太湖不同月份、不同区域水体溶解态磷含量的时空动态变化特征及其与藻类生长的相关性。全湖月平均TSP变化范围为(0.027±0.019)~(0.054±0.042)mg/L,SRP变化范围为(0.009 ± 0.006)~(0.035 ± 0.020) mg/L,夏秋季SRP含量高于春冬季。北太湖区溶解态磷含量普遍高于南太湖区,近岸溶解态磷含量高于离岸。各点位年均TSP变化范围为(0.019±0.011)~(0.104±0.038) mg/L,SRP变化范围为(0.009±0.006)~(0.041±0.022)mg/L。全年SRP变异(53.2%)高于TSP(23.4%)、近岸变异高于离岸、表层高于底层。溶解态磷含量日变化特征不明显,外源磷输入影响太湖水体溶解态磷分布。全年中太湖水体TSP、SRP与Chl-a呈显著正相关,相关系数分别为0.313(P<0.01)、0.284(P<0.01)。

Spatio-tempo Variations of Dissolved Phosphorus Concentrations in Lake Taihu

Total solubility phosphorus(TSP)and solubility reactive phosphorus(SRP)at 9 sampling sites in Lake Taihu were collected during 2010. The spatial and temporal distribution of TSP and SRP, as well as the correlation between different phosphorus fractions and chl-a were analyzed at the same time. Results showed that the monthly average contents of TSP ranged from (0.027±0.019) to (0.054±0.042) mg/L, SRPs were in the range of (0.009±0.006)-(0.035±0.020) mg/L. Additionally, the SRP levels in summer and autumn were normally higher than the other two seasons. Meanwhile, annual average contents of TSP changed from (0.019±0.011) to (0.104±0.038) mg/L, while SRP varied from (0.009±0.006) to (0.041±0.022) mg/L. It was generally observed that dissolved phosphorus concentration in northern area was higher than southern area. The comparison of variation coefficient indicated that SRP mutation(53.2%)was higher than TSP(23.4%) by 29.8%. The diurnal variations of dissolved phosphorus were not obvious. An significant positive correlation between Chl-a and TSP, SRP was observed with the correlation coefficients of 0.313 and 0.284 respectively.