基于附生硅藻的川蔓藻水质综合需求研究

Water quality integrated assessments of Ruppia maritime using epiphytic diatom

选择生长良好的川蔓藻群落,计算其表面附生硅藻的特定污染敏感指数(IPS)和硅藻生物指数(IBD)及其生态类群,以期阐明川蔓藻对水环境的综合需求,为川蔓藻的恢复和保护提供有价值的参考。结果显示,川蔓藻上附生硅藻共36种,分属9科13属,以异极藻属(Gomphonema)、舟形藻属(Navicula)和菱形藻属(Nitzschia)为主,优势种有Cocconeisplacentula var.euglypta,Cymbella tropica,Achnanthidium minutissimum,Nitzschia amphibia和Gomphonema minutum。硅藻指数IPS和IBD显示水体质量为"好"。耐N-自养型和兼性N-异养型生态类群、需氧较高和中等需氧、喜中性类群至喜碱性、微咸水、β-中污和α-中污染性以及富营养性硅藻类群分别大于总数的70%、60%、80%、70%、70%和80%以上。以上结果表明,川蔓藻水体环境pH值7.0～8.0之间,Cl含量大致介于0.1～0.5 g L-1之间,水体N浓度较低,有机污染程度较轻,氧气较为充足,适度的营养物质促进川蔓藻的生长,IPS和IBD可以综合显示川蔓藻对水环境的需求。

The indices of specific pollution sensitivity index （IPS） and standardized biological diatom index （IBD） are applied on Ruppia maritime with good living form to evaluate water ecological .quality based on epiphytic diatom community. There are 36 diatom species belonging to 9 families and 13 genera with the dominant species of Cocconeis placentula var. euglypta, Cymbella tropica, Achnanthidium minutissimum, Nitzschia amphibian and Gomphonema minutum. The results show IPS and IBD vary from 10.3 to 13.6 and from 14 to 14.7, respectively, indicating the good water ecological quality of R. maritime. There are more than 70%, 60%, 80%, 70%, 70% and 80%, respectively, of diatom ecotype of autotrophic and heterotrophic nitrogen uptake metabolism, high and moderate oxygen requirement, circumneutral and alkaliphilous pH, fresh brackish salinity, 13-mesosaprobous and a-mesosaprobous saprobity, and eutrophic state. The results indicate the good water ecological quality of R. maritime is pH 7.0-8.0, C1 concentration 0.1-0.5 g.L-1, relatively low N contents, low organic pollutions, enough oxygen and moderate nutrient concentrations. IPS and IBD can comprehensively indicate the above environment requirements for R. maritime.