澜沧江小湾库区浮游植物初级生产力评估及其时空变化

Assessment of phytoplankton primary productivity and its spatiotemporal changes in Xiaowan Reservoir area of Lancang River

为了解澜沧江小湾库区浮游植物初级生产力及其时空变化,于2017-2019年8月使用叶绿素a法、黑白瓶法和生物量法对小湾库区进行初级生产力测定、估算。结果显示:2017-2019年小湾水库初级生产力(以C计)为0.17~5.26 mgC/(m^(3)·d),三年平均值分别为(2.67±1.10)、(2.68±1.14)、(2.38±1.11)mgC/(m^(3)·d);黑白瓶法测得初级生产力(以溶氧计)为0.87~2.31 mgO_(2)/(L·d),三年平均值分别为(1.23±0.19)、(1.51±0.40)、(1.45±0.33)mgO_(2)/(L·d);生物量变化范围为0.16~5.49 mg/L,三年平均值分别为(1.51±0.56)、(2.42±1.19)、(2.95±1.12)mg/L。三种测量方法中叶绿素a法估算各年份结果最稳定,可作为周年代表值;黑白瓶法测量结果空间变化范围最小,可作为库区均值,生物量易受环境因子影响,不宜估算全年生产力终值。从时空分布看,连续三年黑惠江生产力最高,澜沧江上游最低,三种测量结果呈现出支流>下游>中游>上游的变化趋势,不同年份的初级生产力水平分布基本一致,小湾水库营养盐与透明度是各江段初级生产力主要影响因子。

The primary productivity of Xiaowan Reservoir Area was measured and estimated by the black-and-white bottle method,chlorophyll a method and phytoplankton biomass method to understand the primary productivity of phytoplankton in Xiaowan Reservoir Area of Lancang River and its temporal and spatial changes.Meanwhile,This samples were collected from August 2017 to August 2019.The results showed that the primary productivity(in Terms of C)of Xiaowan Reservoir from 2017 to 2019 ranges from 0.17 to 5.26 mgC/(m^(3)·d),and the mean values of three years(M±SD)were(2.67±1.10),(2.68±1.14)and(2.38±1.11)mgC/(m^(3)·d),respectively.The primary production of the black and white bottle method measured(in dissolved oxygen meter)was 0.87-2.31mgO_(2)/(L·d).(M±SD),the average for three years were(1.23±0.19),(1.51±0.40),(1.45±0.33)mgO_(2)/(L·d),respectively.The biomass varied from 0.16 to 5.49 mg/L,with the mean values of(M±SD)(1.51±0.56),(2.42±1.19)and(2.95±1.12)mg/L.Among the three measurement methods,chlorophyll a method is the most stable and can be used as the annual representative value.The measurement results of the black and white bottle method have the smallest spatial variation range,and can be used as the mean of the reservoir area.The biomass is easily affected by environmental factors,so it is not suitable to estimate the final annual productivity.From the perspective of spatial and temporal distribution,the productivity of Heihui River was the highest and the productivity of Lancang River was the lowest in the upper reaches of Lancang River for three consecutive years.The results of the three measurement methods showed a trend of variation of tributary>downstream>middle reaches>upstream.The distribution of primary productivity in different years wass basically the same,and the nutrient and transparency of Xiaowan reservoir were the main influencing factors of primary productivity in each river section.