洞庭湖水体叶绿素a时空分布及与环境因子的相关性

Spatial-Temporal Distribution of Chlorophyll-a and Its Correlation with Environment Factors in Dongting Lake

2013年6月至2014年5月逐月对洞庭湖水体叶绿素a质量浓度和主要环境因子进行测定,分析洞庭湖水体叶绿素a质量浓度的时空分布特征,探讨洞庭湖水体叶绿素a质量浓度与环境因子的相关性。结果表明,洞庭湖水体叶绿素a质量浓度为0.11~8.62 mg/m^3,年均值为(1.89±1.23)mg/m^3,属贫营养;叶绿素a质量浓度随季节变化明显,总体呈现夏、秋季明显大于冬、春季的规律;在空间上,总体表现为西洞庭湖和东洞庭湖明显大于南洞庭湖。全湖叶绿素a质量浓度与水温、电导率、COD和TP呈极显著正相关,与DO、NH3-N、TN和TN/TP呈极显著负相关,与NO-3-N呈显著负相关,与p H和透明度无显著相关性。全湖TN/TP的年均值为28.5,磷可能是洞庭湖水体浮游植物生长的限制性营养盐。

The spatial-temporal distribution characteristics of chlorophyll-a concentration was analyzed and the correlation between chlorophyll-a concentration and environmental factors were also studied, based on the monthly monitoring data in Dongting Lake from June 2013 to May 2014. The results showed that the chlorophyll-a concentration in Dongting Lake ranged from 0. 11 to 8.62 mg/m3 , with the annual average value of （ 1.89 ± 1.23） mg/m3 ,which indicated that Dongting Lake at oligotrophic level. There was an obvious temporal and spatial variation of chlorophyll-a concentration. In time, the average concentration of chlorophyll-a was found to be obviously higher in summer and autumn than in winter and spring generally. In space, the average concentration of chlorophyll-a was found to be obviously higher in West Dongting Lake and East Dongting Lake than in South Dongting Lake generally. Significantly positive correlation was found between chlorophyll-a and water temperature, conductivity, COD and TP, significantly negative correlation was found between chlorophyll-a and DO, NH3-N, TN and TN/TP, and negative correlation was found between chlorophyll-a and NO3 -N, but no significant correlation was found between chlorophyll-a and pH and transparency in Dongting Lake. The ratio of TN/TP was 28.5, and phosphorous might be the nutrient limiting phytoplankton growth in Dongting Lake.