富营养化水体中铜锈环棱螺促进苦草生长和水质改善研究

Bellamya aeruginosa promote the growth of Vallisneria natans and improve water quality in high nutrient environment

铜锈环棱螺(Bellamya aeruginosa)和苦草(Vallisneria natans)是淡水生态系统中常见的生物类群,两者之间存在直接或间接的相互作用,对维持生态系统的多样性和功能的稳定具有重要作用。本研究通过在富营养化水体中构建4组(单植苦草组、苦草+低生物量环棱螺、苦草+中生物量环棱螺、苦草+高生物量环棱螺)小型水生态系统,研究铜锈环棱螺和苦草的复合作用对水质改善和苦草生长的影响。结果表明:(1)铜锈环棱螺可有效去除水体悬浮颗粒和藻类细胞,提高水体透明度,改变可溶解性氮、磷形态和含量,促进苦草的生长;(2)苦草的株高、无性分株数以及系统中氮磷的去除率与铜锈环棱螺生物量存在显著的正相关关系;(3)与对照组苦草逐渐消亡的比较可知,光照条件是苦草消亡的主要原因,而铜锈环棱螺对可溶解性营养盐含量及其形态的影响是促进实验组苦草快速生长繁殖的重要因素。研究表明,在富营养化水体中共同移植铜锈环棱螺和苦草可以明显改善水质状况,促进苦草生长繁殖,但这种作用与铜锈环棱螺生物量的配置有紧密关系。

Bellamya aeruginosa and Vallisneria natans was widely distributed in freshwater ecosystem in china,there exists the obviously direct and indirect correlations between Bellamya aeruginosa(Reeve)and Vallisneria natans(Lour.),which play important roles in the maintaining of the diversity and function of freshwater ecosystem.In this study,we constructed four groups of mesocosms(V.natans,V.natans+low B.aeruginosa biomass,V.natans+middle B.aeruginosa biomass,V.natans+high B.aeruginosa biomass)to study the synergistic effect of B.aeruginosa and V.natans on V.natans growth and the health of water environment.The results showed that(1)the presence of B.aeruginosa significantly reduced the content of suspended particles and algae,improved the water transparency,and promote the growth of V.natan.(2)The growth conditions of V.natans and nitrogen and phosphorus removal are positive correlation with the biomass of B.aeruginosa.(3)Compared with the control group,we inferred that light may be the main reason for V.natans's extinction,but the change of nutrient level and forms are the main factors promoting the growth of V.natans in B.aeruginosa groups.The study suggested that the co-existence of V.natans in B.aeruginosa could promote the growth of V.natans and improve water quality in high nutrient environment,but such effects depend on the biomass of B.aeruginosa.