Exploration of relationships between phytoplankton biomass and related environmental variables using multivariate statistic analysis in a eutrophic shallow lake:A 5-year study

Understanding the process of the changing phytoplankton patterns can be particularly useful in water quality improvement and management decisions.However,it is generally not easy to illustrate the interactions between phytoplankton biomass and related environmental variables given their high spatial and temporal heterogeneity.To elucidate relationships between them,in a eutrophic shallow lake,Taihu Lake,relative long-term data set of biotic and abiotic parameters of water quality in the lake were conducted using multivariate statistical analysis within seasonal periodicity.The results indicate that water temperature and total phosphorus(TP)played governing roles in phytoplankton dynamics in most seasons(i.e.temperature in winter,spring and summer; TP in spring,summer and autumn); COD(chemical oxygen demand)and BOD(biological oxygen demand)presented significant positive relationships with phytoplankton biomass in spring,summer and autumn.However,a complex interplay was found between phytoplankton biomass and nitrogen considering significant positive relationships occurring between them in spring and autumn,and conversely negative ones in summer.As the predatory factor,zooplankton presented significant grazing-pressure on phytoplankton biomass during summer in view of negative relationship between them in the season.Significant feedback effects of phytoplankton development were identified in summer and autumn in view that significant relationships were observed between phytoplankton biomass and pH,Trans(transparency of water)and DO.The results indicate that interactions between phytoplankton biomass and related environmental variables are highly sensitive to seasonal periodicity,which improves understanding of different roles of biotic and abiotic variables upon phytoplankton variability,and hence,advances management methods for eutrophic lakes.     

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索风营水电站Dr2号危岩体破坏模式分析

在专门性工程地质勘察的基础上,系统分析了Dr2危岩体的边界条件、形成机理及破坏模式,并简要介绍了目前所采取的处理措施。     

黄陵至延安高速公路k295+750-k296+050段滑坡稳定性分析与治理

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环境税收制度是未来中国环境政策改革的突破口，相对于其它的环境政策如排污收费与排污权交易等，环境税收其经济效益与环境效益明显，开征环境税收有重要的意义，但在短期内，我国实施环境税收制度的条件尚不成熟，环境政策体系应该采取税费并存，并逐步过渡到以环境税为主的方式。     

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利用2kg模拟焦炉，进行了首钢炼焦配煤与北京市石景山区生活垃圾中的废塑料的共焦化实验。研究结果表明，添加废塑料有提高焦油收率和减少水的收率的趋势；但添加废塑料对成焦率、焦油产率及水产率的影响随废塑料处理方法和废塑料添加比例的不同而有差异；采用废塑料型煤或废塑料型煤破碎物与配煤共焦化在提高废塑料添加比例方面具有较大优势。     

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