阳澄西湖叶绿素a的时空分布及其与环境因子的关系

根据2015年3月~2016年2月对阳澄西湖水体叶绿素a和水质理化因子的逐月监测结果表明,阳澄西湖叶绿素a浓度存在着明显的季节变化,其全年变化范围为11.93μg/L~66.67μg/L,平均值为27.54μg/L±20.34μg/L。最小值出现在2016年1月,最大值出现在2015年8月。叶绿素a在空间分布上也存在着差异,叶绿素a在断面Ⅰ浓度最高,其次是断面Ⅱ和断面Ⅳ,断面Ⅲ最低。根据综合营养状态指数法计算阳澄西湖营养状态,得出综合营养状态指数范围为50.7~59.3,年平均值为55.6,水体总体处于"轻度富营养"状态。综合pearson相关系数和逐步回归方程,结果表明叶绿素a与水温呈极显著正相关,与溶解氧呈极显著负相关,与透明度呈极显著负相关。结合生产实践对阳澄西湖总氮(TN)、总磷(TP)和氮磷比(N/P)取对数进行pearson相关性分析并建立一元线性回归方程,结果表明叶绿素a浓度与总氮无相关关系,与总磷呈极显著正相关,与氮磷比呈极显著负相关,阳澄西湖可能是一定程度的磷限制湖泊。

TEMPORAL AND SPATIAL DISTRIBUTION OF CHLOROPHYLL A AND ITS RELATIONSHIP WITH ENVIRONMENTAL FACTORS IN YANGCHENG WEST LAKE

Monthly monitoring from March 2015 to February 2016,temporal-spatial dynamics of chlorophyll-a in the Yangcheng West Lake and also the potential influencing factors were analyzed.The results showed that,seasonal variation of chlorophyll-a in were obvious,ranging from 11.93 μg/L to 66.67 μg/L and with an annual mean value of 27.54 μg/L± 20.34 μg/L.The minimum and maximum value of chlorophyll-a concentration appeared in January 2016 and August 2015,respectively.The concentration of chlorophyll-a was different in the spatial distribution.The content of chlorophyll-a reached the highest in the section Ⅰ,followed by section Ⅱ and Section Ⅳ,and section Ⅲ was the lowest.The comprehensive trophic state index was 50.7-59.3,and the annual mean value was 55.6.In general,the lakes was in a state of mesotrophic.According to Pearson correlation and stepwise regression analyses,chlorophyll-a was significantly positively correlated with water temperature and negatively with dissolved oxygen and transparency.Pearson correlation analysis was further carried ou twith total nitrogen (TN),total phosphorus (TP),and the ratio of nitrogen and phosphorus (N/P).Chla was found to correlated weakly with total nitrogen while significantly positively with total phosphorus,and negatively correlated with N/P ratio,suggesting a limitation by phosphorus.