棘洪滩水库浮游藻类变化及富营养化防治

详细分析了2004~2006年度棘洪滩水库浮游藻类的细胞密度及种群结构变化。2004年进水口与放水口藻类细胞密度年均值分别为3.892×106/L和2.269×106/L,冬季以硅藻为主,春季以隐藻、金藻为主,夏、秋季以蓝藻为主。2005年进水口与放水口藻类细胞密度年均值分别为6.654×106/L和5.903×106/L,冬、春季以硅藻、隐藻为主,夏季以绿藻为主,秋季则以蓝藻为主。2006年进水口与放水口藻类细胞密度年均值分别为3.001×106/L和3.687×106/L,夏末至秋季绿藻占优势,代替了先前在此阶段占优势的蓝藻,其他季节多以硅藻为主,隐藻和金藻分别在冬季和春季占有一定比例,说明2006年的水质状况较2004年、2005年有所改善。棘洪滩水库藻类峰值出现在夏末和秋季,此阶段水库的水质呈中富营养状态,其他月份为中营养或贫营养状态。Shannon-weaver多样性指数显示,目前水库的水质总体呈中度污染。入库的源水质量对水库水质影响很大,控制引入的源水质量并采取相应的生物防治措施可有效避免水库发生富营养化。

Phytoplankton variation and eutrophication prevention in Jihongtan Reservoir

The changes of cell density and community composition of phytoplankton in 2004, 2005 and 2006 in the Jihongtan Reservoir were analyzed in detail. The annual mean cell densities of phytoplankton were 3.892 × 10^6/L at the inlet and 2.269 × 10^6/L at the oudet in 2004, and the community composition of phytoplankton was dominated by diatoms in winter, cryptomonad and Chrysophyta in spring and blue algae in summer and autumn. In 2005, the annual average cell densities of phytoplankton were 6.654 ×10^6/L at the inlet and 5.903 × 10^6/L at the outlet, and dominant species were diatoms and cryptomonad in winter and spring, green algae in summer and blue algae in autumn. The water quality of the reservoir was better in 2006 than in 2004 and 2005. The annual average cell densities of phytoplankton were 3.001 × 10^6/L at the inlet and 3.687 ×10^6/L at the outlet in 2006; diatoms were the main phytoplankton in all seasons except the period from the end of summer to autumn, when green algae, instead of blue algae as in 2004 and 2005, were the dominant phytoplankton. In the meantime, cryptomonad and Chrysophyta existed in winter and spring, respectively. The peak value of cell density appeared at the end of summer and autumn, when the water in the reservoir was in a eutrophic state rather than the mesotrophic or oligotrophic states of other months. The Shannon-weaver diversity index shows that water in Jihongtan Reservoir was medium-polluted. The water quality of the Jihongtan Reservoir was influenced greatly by its water sources. In order to avoid eutrophication, it is important to control the quality of the source water and to adopt biological control methods in the reservoir.