安邦河湿地浮游植物及营养现状评价

Phytoplankton and Trophic Levels in Anbang River Wetland

于2005年7月至2006年5月对安邦河湿地浮游植物进行调查，通过浮游植物结合综合营养状态指数法对其营养现状进行评价。调查共发现浮游植物8门104种，以绿藻最多（49种），其次蓝藻（25种）、硅藻（18种）。营养指示种结果表明处于中营养化水平。浮游植物年平均数量为182．44×10^4ind·L^-1，生物量为2．92mg·L^-1。各站位的数量显示安邦河湿地处于中、富营养化水平，而生物量表现为中营养化水平（除8#、10#站位外）。生物量以硅藻占优（年平均占40．75％），为硅藻型，属中营养化水平。基于生物量的Shannon-Veaner指数评价结果显示，除了春季的3#、4#、6#、8#和秋季的4#站位是贫营养外（〉3．30），其他均为中营养化水平（0．93—3．30），说明安邦河湿地整体已处于中营养化水平。各季节各站位的综合营养状态指数均在30～50之间，均为中营养化状态，支持了浮游植物评价结果。由此可见，安邦河湿地处于中营养状态，有向富营养化过渡的趋势，通过监测浮游植物可以正确评价其水质状况。

An investigation was carried out in Anbang River wetland, a type of high frigid swamp, from July 2005 to May 2006. Phytoplankton diversity of 104 taxa, belonging to Chlorophyta （49）, Cyanophyta （25）, Baeillariophyta （18）, Chrysophyta （4）, Euglenophyta （3）, Xanthophyta （2）, Cryphophyta （2）, and Pyrrophyta （1）, were found. There were 17 eutrophic taxa, 34 mesotrophic taxa and 25 oligotrophie species were indentifiod in the studied period. Typical trophie indicators, such as Aphanizomenon flos- quae, Microcystis aeruginosa, Melosira granulate, and so on, which are usually associated with eutrophic environments, were monitored and were the dominant species in 1 #, 5 #, 9 # sampling stations, with ratios of 51.31% , 58.28% , and 53.37% , respectively. Trophie taxa showed that the trophie status of Anbang river wetland was mesotrophers. Total mean abundance was 183.32 × 10^4 ind · L^-1 and biomass was 2.92 mg· L^-1 , respectively, with an order of temporal distribution of abundance and biomass summer 〉 autumn 〉 spring. The abundance of sampling stations were from 42. 12 × 10^4 ind · L^- 1 to 178.53 × 10^4 ind · L^-1 in spring, at 98.04× 10^4-396.57 × 10^4 ind · L^-1 in summer, and at 58.45 × 10^4 -323.93 × 10^4ind · L^-1 in autumn, biomass in spring from 1.21 mg · L^-1 to 3.02 mg · L^-1 , in summer at 2.57-4.80 mg· L^-1, and in autumn at 1.34-4.35 mg·L^-1. Based on the criteria of trophie status in phytoplankton in China： （1） abundance 〈3 × 10^5 ind · L^-1 or biomass at 1-1.5 mg · L^-1 is oligotropher; （2） abundance at 3 × 10^5-10 × 10^5 ind · L^-1 or biomass at 1.5-5 mg · L^-1 is mesotrophers; （3） abundance 〉 10 × 10^5 ind · L^-1 or biomass 〉 5 mg · L^-1 is eutropher. There was differentia in trophie status based on the abundance and biomass. Results of abundance showed it was mesotrophers ＆ eutropher, but biomass was mesotrophers except 8# and 10# sampling stations. Biomass of Bacillariophyta was dominant in spring （62.16%）, autumn （41.30%）, and mean （40.75%）, only in summer was non-dominant species （27.59%）, merely 〈 Chlorophyta （33.95%） , revealed the phytoplankton community was Baeillariophyta type, was mesotrophers. Diversity index is a useable method in evaluating water trophic starus. Species number, Margalef＇ s index, Shannon-Veaner＇ s index and Pielou＇ s index were collected. Correlation analysis between the species number and Margalef＇s index in Anbang River wetland indicated that had a positively significant correlation （Spearman r = 0. 988, n = 30, P 〈 0. 001 ）, Shannon-Veaner, s index had a positively significant correlation with Pielou＇ s index （ Spearman r = 0.875, n = 30, P 〈 0. 001 ）, there was no significant correlation between other diversity indexes （P 〉 0.05, n = 30）. Therefore, Margalef＇ s index and Shannon-Veaner＇s index were collected to measure phytoplankton community diversity. However, Margalef＇s index is strongly correlate to rare species, and the results maybe error, in contrast, Shannon-Veaner＇s index is one of best diversity index, which can be preferably reflect the phytoplankton community structure. Shannon-Veaner＇s index indicated that in spring there were 9, in summer 4, and in autumn 8 sampling stations, which value 〉 3.30, showed most of sampling stations were oligotrophic water, not same as the indicator species and biomass estimation, based on abundance. Shannon-Veaner＇s index based on biomass suggested that 3#, 4#, 6#, 8# in spring, and 4# in autumn 〉3.30, were oligotrophic, other between 0.93 and 3.30, were mesotrophers, sustained results of indicator species and biomass evaluation. Phytoplankton compositions are affected by different environmental factors such as nutrient, pH, light, temperature, and so on, so trophic status should be monitored by vary methods. Trophic level indexes （TLI） based on chlorophyll-a （Chl-a）, total nitrogen （TN）, total phosphorus （TP）, and secchidisk depth （SD） were conducted, TLI between 30 and 50 in all sampling stations in three seasons, and 5#, 9# sampling stations in summer, which TLI were 49. 459 and 49. 731, nearly the eutrophic status. TLI demonstrated that water in Anbang river wetland was mesotrphic, were likely to maintain the results of phytoplankton. In summary, water quality was well, belonging to mesotrophic, but had the potential to eutrophication. Though water trophic status assessment based on phytoplankton may seem clear enough, it served as a valuable example for the future monitoring of the Anbang River wetland water quality.