应用草型塘模型生态系统研究化学品的整体生态效应

USE OF MODEL GRASSY POND OF ECOSYSTEM TO EVALUATE THE HOLISTICALLY ECOLOGICAL EFFECTS OF CHEMICAL STRESS

本文叙述草型塘模型生态系统的结构、功能及应用于评价化学品引起生态效应的可能性。模型塘由８个３ｍ×１ｍ×１ｍ（Ｖ＝３ｍ￣３）的玻璃钢水槽组成。每个槽的底部铺设１０ｃｍ厚的带有水生生物种子、孢子和卵子的河泥，灌注自来水，添加一定量的ＫＮＯ＿３和ＮａＨ＿２ＰＯ＿４．使起始氮、磷含量达到中－富营养水平。在室外自然光照条件下培养，实验历时４个多月。经１个多月的培养，各槽即形成结构复杂的沉水植物群落，除各种常见的沉水植物外，尚有多种藻类、浮游动物、底栖动物及微生物。各群落之间的相似性较好，藻类、浮游甲壳类及底栖动物多样性指数变异系数分别为１７．７％、１８．０％和３６．０％。群落功能稳定，９月中旬各槽群落总产氧量平均为５．７５±０．３０ｇ／ｍ￣２·ｄ’Ｐ／Ｒ比值平均为１．２６±０．０７，二者的变异系数分别为５．２％和５．６％。经单甲脒农药污染影响实验，本模型生态系统中的群落结构及功能产生一系列明显反应。说明草型塘模型生态系统结构、功能比较复杂，稳定，可比性较强，对药物污染反应灵敏，是生态系统水平上生态效应评价的良好工具。

his paper deals with the community structure and metabolism of the model grassy pond ecosystem and the possibility of its application to evaluate the effects of chemical contamina-tion on ecosystems,The model pond of ecosystems consisted of eight glass fiber tanks each inadimension of 3m × 1m ×1m(V=3m￣3). Each tank was filled with tap water,together with10cm thick river sediments containing seeds,cysts and eggs of aquatic organisms on its bot-tom, Some KNO_3 and NaH_2PO were added to keep water nutrients close to a meso-eutrophiclevel. Then they were incubated under the outdoor ambient condition from June through Oc-tober。One month after incubation, a submerging community , including macrophytes , algae,zooplankton , benthos and microorganisms, was growing up luxuriantly and the communitymetabolism reached steady conditions, The high similarities among the communities in vari-ous tanks were found,and the variabilities of the diversity index for algae , zooplankton andbenthos were 17.7%, 18.0%and 36.0%, respectively. Gross production was averaged 5.75±0.30gO_2/m￣2·d,with a P/R ratio of1.26±0.07.The variabilities of both gross productionand P/R ratio were 5.2%and 5.6%,respectively.Preliminary monitoring results indicate that this kind of mesocosm was a sensitive anduseful tool for evaluating ecological effects of chemical stress on ecosystem level.