富营养化湖泊叶绿素a分析方法比较研究

Comparison between Analysis Methods of Chlorophyll a for Eutrophic Lakes

叶绿素a浓度是表征水体中浮游藻类生物量水平的常用指标,但是缺乏理想的规范。为筛选出更适用于富营养化湖泊藻类叶绿素a的分析方法,研究于2006年7月-2007年6月期间,每月从滇池取10个水样,采用常用的2种叶绿素a分析方法测定其叶绿素a浓度,并通过显微分析方法获得藻类湿重数据。通过四波段法和两波段法的比较,计算得到如下数据结果:(1)四波段法的相对偏差平均值3.0%比两波段法的3.8%小;(2)四波段法和两波段法≤5%的相对偏差数据比例分别占83.3%和70.8%;(3)四波段法和两波段法叶绿素a浓度与藻类湿重的相关系数分别为0.761(n=120,p<0.001)和0.606(n=120,p<0.001);(4)四波段法和两波段法(叶绿素a/藻类湿重)比值的相对标准偏差分别44.8%和61.2%。结论认为四波段法比两波段法更稳定,更适用于富营养化湖泊藻类生物量的检测。

Chlorophyll a concentration （chkl） is widely used as an indicator of phytoplankton biomass, but there is no ideal protocol. In order to find more suitable chla analysis method in monitoring eutrophic lakes, two common methods named with two-band method and quad-band method were simultaneously performed in Dianchi Lake, Yunnan Province. 10 samples from Dianchi Lake were monthly obtained from July 2006 to June 2007, and chla were analyzed by the two methods above, and phytoplankton wet weight were analyzed by macroscopic counts and microscopic measurement. Through the comparison of quad-band method and two band method, results indicated that mean value of 3.0% R.D. from quad-band method was lower than the mean value of 3.8% R.D. from two-band method. The proportion of R.D. less than or equal to 5.0% from quad-band method was 83.3%, and that from two-band method was 70.8%. The correlation coefficient of chla-phytoplankton wet weight from quad-band method was 0.761 （n=120, p〈0.001）, while that from two-band method was 0.606 （n=120, p〈0.001）. The value of R.S.D. of chla/wet weight ratios from quad-band method was 44.8%, and that from two-band method was 61.2%. It is concluded that the quad-band method is more stable, and more suitable for detection of phytoplankton biomass in eu- trophic lakes,