人工湖蓝绿藻浓度与水质和气象条件关系研究

Study on the Relationship between Blue-Green Algae Concentration and Water Quality and Meteorological Conditions in Artificial Lakes

摘要: 水体的富营养化程度直接或间接地影响着藻类浓度的高低，同时藻类浓度也受外部环境因素的影响。为了解水体中藻类的浓度与水质和气象条件的关系，本文从2017年5月初开始至2017年10月，每月采取传统实验方法对云师大人工湖中水温、pH、氨氮、总磷、硝酸盐氮、总氮以及叶绿素a浓度等指标进行了测量，并且从校内气象站获取了CO₂的浓度、总辐射、风速和环境温度等指标。通过相关性分析，结果表明：1) 北湖的藻类爆发特征比较明显，主要集中在6~7月份；2) 在研究的三个湖泊中，1号湖总氮的平均含量为0.919 mg/L，且硝酸盐氮平均含量为0.368 mg/L，氨氮平均含量为0.611 mg/L；总磷的平均含量为0.007 mg/L，很明显，该湖的总氮含量偏高，氮主要来源于氨氮；总磷含量很低，造成了氮磷比很高，磷成为限制因子；3) 南湖总氮平均含量为0.965 mg/L，氨氮平均含量为0.715 mg/L，硝酸盐氮平均含量为0.314 mg/L；总磷平均含量为0.013 mg/L。总氮含量远高于总磷含量，且氮主要来源于氨氮，由氮磷比与叶绿素浓度相关性趋势图得出，南湖的氮磷比与叶绿素整体上呈负相关，相关系数为0.289 (除该湖4号采样点的数值异常偏高)，二者相关性较低；4) 北湖总氮平均含量为0.508 mg/L，氨氮平均含量为0.376 mg/L，硝酸盐氮平均含量为0.146 mg/L；总磷平均含量为0.0179 mg/L。总氮含量高于总磷含量，且氮同样主要来源于氨氮，根据氮磷比与叶绿素浓度相关性示意图，二者相关性较低；5) 气象观测和叶绿素a的测定为六个月，相关性分析采用三个湖六个月的气象数据和六个月的叶绿素a进行分析，结果显示，CO₂的浓度与叶绿素a的相关性较强，呈负相关；环境温度与叶绿素a浓度呈负相关，相关系数比CO₂大；风速与叶绿素a的关系并不大，人工湖受风速影响较小；总辐与叶绿素a的相关性也不是很大；总体来看，气象因子在一定程度上也影响着蓝绿藻的爆发。

Abstract: The eutrophication degree of water body directly or indirectly affects the algae concentration, and the algae concentration is also affected by external environmental factors. In order to understand the relationship between the concentration of algae in water and water quality and meteorological conditions, traditional experimental methods were used in this paper to meas-ure the water temperature, pH, ammonia nitrogen, total phosphorus, nitrate nitrogen, total ni-trogen and chlorophyll a concentration in the artificial lake of Yunnan Normal University every month from the beginning of May 2017 to October 2017, and the CO₂ concentration, total radiation, wind speed and environmental temperature were obtained from the weather station in the school. Through the correlation analysis, the results show that: 1) The characteristics of algae outbreaks in North Lake are obvious, mainly in June-July; 2) In the three lakes studied, the av-erage content of total nitrogen in Lake No. 1 is 0.919 mg/L, the average content of nitrate nitrogen is 0.368 mg/L, and the average content of ammonia nitrogen is 0.611 mg/L; the average content of total phosphorus is 0.007 mg/L. Obviously, the total nitrogen content in the lake is high, and the nitrogen mainly comes from ammonia nitrogen. The total phosphorus content is very low, resulting in a high ratio of nitrogen to phosphorus, and phosphorus becomes the limiting factor; 3) The average content of total nitrogen, ammonia nitrogen and nitrate nitrogen in Nanhu Lake is 0.965 mg/L, 0.715 mg/L and 0.314 mg/L, respectively. The average content of total phosphorus is 0.013 mg/L. The total nitrogen content is much higher than the total phos-phorus content, and the nitrogen mainly comes from ammonia nitrogen. According to the trend chart of the correlation between the ratio of nitrogen to phosphorus and the concentration of chlorophyll, the ratio of nitrogen to phosphorus in South Lake is negatively correlated with chlorophyll as a whole, with a correlation coefficient of 0.289 (except for the abnormally high value at the No. 4 sampling point in the lake), and the correlation between them is low; 4) The average content of total nitrogen, ammonia nitrogen and nitrate nitrogen in North Lake is 0.508 mg/L, 0.376 mg/L and 0.146 mg/L, respectively. The average content of total phosphorus is 0.0179 mg/L. The total nitrogen content is higher than the total phosphorus content, and the nitrogen also mainly comes from ammonia nitrogen. According to the correlation diagram between the nitrogen phosphorus ratio and chlorophyll concentration, the correlation between the two is relatively low; 5) The meteorological observation and determination of chlorophyll a lasted for six months, and the correlation analysis used the meteorological data of three lakes for six months and chlorophyll a for six months. The results showed that the correlation between CO₂ concentration and chlorophyll a was strong and negative. Environmental temperature is negatively correlated with chlorophyll a concentration, and the correlation coefficient is larger than that of CO₂. The relationship between wind speed and chlorophyll a is not great, and the artificial lake is less affected by wind speed; the correlation between total radiation and chlorophyll a is not very great; generally speaking, meteorological factors also affect the outbreak of blue-green algae to some extent.