利用环棱螺调控池塘水质的实验生态学研究

Environmental biology of Bellamya sp.in regulating pond water quality

设计了3组微尺度可控实验研究环棱螺的生态功能及其对水体各要素的影响机制,结果表明:受控条件下,环棱螺代谢释放氮、磷,使水体中不同形态氮、磷浓度均明显增加,430h后溶解性总氮和溶解性总磷分别较初始增加0.73～2.56倍和1.85～3.41倍,且高营养盐浓度条件下,环棱螺的代谢释放受到抑制。环棱螺对水体悬浮颗粒物具有显著的短期促沉效能,且与水体中悬浮颗粒物浓度及成分有关,初始浊度较高的高岭土溶液和藻华水体的沉降速率与螺密度呈正比。短期内环棱螺能显著降低水体叶绿素a浓度,且去除率与螺密度呈正比,但随着时间增加叶绿素a浓度迅速升高。环棱螺对微囊藻的摄食和营养盐释放促进绿藻取代蓝藻成为优势种。

Three micro-scale controlled experiments were established to examine the ecological function of Bellamya sp.and their affecting mechanisms upon water.Due to the N and P release through the Bellamya sp.metabolism under controlled conditions,the concentrations of different N and P forms in water were obviously increased.After 430 hours incubation,the concentrations of dissolved total nitrogen（DTN） and dissolved total phosphorus（DTP） in water were increased by 0.73-2.56 times and 1.85-3.41 times,respectively.Under the high nutrient concentrations,the N and P release by Bellamya sp.was inhibited.Meanwhile,Bellamya sp.showed a positive effect on the short-term deposition of suspended particulate matter（POM）,which was related to the constituents and concentrations of POM.The sedimentation rates in both kaolin-and eutrophic water with high initial turbidity showed significant positive relationship with snail density.Furthermore,Bellamya sp.greatly reduced the chlorophyll-a concentration in water in a short period,and the removal rate was positively correlated with snail density.However,the chlorophyll-a concentration was increased rapidly with increasing incubation time.The feeding activities of Bellamya sp.and the consequent nutrient release stimulated the chlorophyta instead of cyanobacteria as the dominant species.