太湖螺类的实验生态学研究——以环棱螺为例

Studies on the experimental biology of snail in Lake Taihu: a case study of Bellamya spp.

通过室内实验探讨环棱螺营养盐释放的影响因子及环棱螺对水体悬浮物、透明度及浮游植物的影响等生态特性．结果表明:温度及进食状况对环棱螺的营养盐释放均有显著影响．15℃时,环棱螺氨氮的释放速率约为55．60±4．95μg／(g·d),磷酸根的释放速率约为2．073±0．120μg／(g·d);而25℃时,环棱螺磷酸根的释放速率是2 819±0．075μg／(g·d),表明在一定温度范围内,环棱螺营养盐的释放速率随温度升高而增加,且进食状态下环棱螺的营养盐释放速率高于饥饿状态．此外,环棱螺虽在短时间内可提高水体的透明度,但其释放的营养盐可引起局部水体溶解态氮磷含量的增加,在没有其它初级生产者争夺营养盐和光照等资源的情况下,水体中藻类的再生速率会加快,环棱螺难以对藻类的增殖起到抑制作用．南此建议在利用螺类进行生态调控的过程中,必须与沉水植物的恢复紧密结合,通过合理的空间搭配,实现水生态系统的恢复与健康发展．

To study the factors affecting the nutrient release of Bellamya sp. , laboratory simulation experiments were carried out, and other traits of Bellamya sp. such as the effects of Bellamya spp. on suspended substance in the water column, water transparency and phytoplankton in the system were also investigated. Results showed that temperature and the amount of food had great influence on nutrient release of Bellamya sp. At 15℃ , the release rates of ammonia nitrogen and phosphate phosphorus by Bellamya spp. were 55.60（ ± 4.95 ） μg /（ g · d） and 2. 073 （ ± 0.1203 ） μg /（ g · d）, respectively ; at 25 ℃ , the release rate of phosphate phosphorus was about 2.819 （ ± 0. 075） μg/（ g · d）. So the release rate of nutrient increased at an enhanced temperature , meanwhile nutrient release rate of snail eating food was higher than it that eating nothing. Bellamya sp. could increase the transparency of water on a short term, but the release of nutrients increased the contents of nitrogen and phosphorus in water, which in turn accelerated the regeneration of phytoplankton. Bellamya sp. can not control the production of algae completely, but their improving the secchi-disk depth of water is helpful for the growth and restoration of submerged macrophytes. It is suggested that the combination of biomanipulation of snails and restoration of submerged macrophytes will be an important technical way to control the eutrophication and improve water environment.