| 1 | Environmental factors regulating cyanobacteria dominance and microcystin production in a subtropical lake within the Taihu watershed,China显示文摘Understanding the pattern of phytoplankton and their dependence on water quality variables, can help the management of eutrophic lakes. The aim of this study was to determine water quality and environmental factors associated with cyanobacteria dominance and microcystin production in Qingshan Lake, a subtropical lake located in the headwater of the Taihu watershed, China. Water samples collected monthly from 10 study sites in Qingshan Lake were analyzed for the species distributions of freshwater algae and physico-chemical parameters including total nitrogen (TN), ammonia (NH4+-N), nitrate (NO3--N), total phosphorus (TP), and chlorophyll a (Chl-a) from June, 2008 to May, 2009. Qingshan Lake was found to be eutrophic, based on the calculated trophic state index (TSI). The average TN of 4.33 mg/L during the study period exceeded the Surface Water Quality Standards of China. TP was significantly correlated with relative abundance of cyanobacteria and Microcystis biovolume, indi- cating its important role in regulating cyanobacteria. Microcystis, Anabaena, and Oscillatoria were dominant cyanobacteria in Qingshan Lake from June to November, 2008. Cyanobacteria dominance was regulated by water temperature and TP. Principal component analysis further indicated that microcystin production was most affected by water temperature, TP, and cyanobacteria biomass. Results suggest that the control of TP in summer can mitigate cyanobacteria dominance and microcystin production in Qingshan Lake, and close monitoring should be undertaken in summer. | Wan-min NI Jian-ying ZHANG Teng-da DING R.Jan STEVENSON Yin-mei ZHU | 2012 | Journal of Zhejiang University-Science A(Applied Physics & Engineering)2012，13，4： | 4 |
| 2 | Assemblage-based biomonitoring of freshwater ecosystem health via multimetric indices:A critical review and suggestions for improving their applicability显示文摘Freshwater biota are more comprehensive and direct indicators of biological impacts,and more meaningful to the public than water quality or physical habitat surrogates.Freshwater biotic data and the multiple biological indicators developed from them offer a much richer array of data for assessing the impacts of pollution controls than a limited set of physical or chemical measures.In recent decades,assemblage-based assessments by ecologists,environmental scientists,and water quality agencies have been employed globally for determining the condition of,and threats to,freshwater ecosystems.A key step in this advance has been the development of multimetric indices(MMIs)or indices of biotic integrity(IBIs)based on quantitative assessments of algae,macrophyte,macroinvertebrate,fish or riparian bird assemblages.In Europe,where biological assemblages are mandated for assessing freshwater ecosystem health,many indices are multimetric.However,the proliferation of MMIs globally has not always occurred through the application of rigorous study designs and monitoring protocols,nor have they always effectively incorporated functional metrics,stressor assessments,and statistical analyses.Therefore,in this review,we discuss eleven major concerns with the development and application(including logistical limitations)of multimetric indicators based on freshwater biota to encourage more rigorous and widely applicable(transferable)MMI use and implementation.Specifically,our concerns focus on reference conditions;sampling effort,methods,and season;trophic guild definition;metric comprehensiveness,options,screening and scoring;and MMI validation.MMIs could also benefit from increased attention to ecological mechanisms and metric development,to further improve our understanding of anthropogenic impacts as well as rehabilitation effects on freshwater ecosystems globally.Paying closer attention to study designs,ecological mechanisms and metric development should further improve our understanding of anthropogenic impacts and better facilitate rehabilitation of degraded freshwater ecosystems,as well as aiding in the conservation of healthy freshwater ecosystems globally. | Robert L.Vadas Jr. Robert M.Hughes Yeon Jae Bae Min Jeong Baek Orestes Carlos Bello Gonzáles Marcos Callisto Débora ReisdeCarvalho Kai Chen Maria T.Ferreira Pablo Fierro Jon S.Harding Dana M.Infante C.J.Kleynhans Diego R.Macedo Isabela Martins Norman Mercado Silva Nabor Moya Susan J.Nichols Paulo S.Pompeu Renata Ruaro Deborah R.O.Silva R.Jan Stevenson Bianca de Freitas Terra Christa Thirion Douglas Ticiani Lizhu Wang Chris O.Yoder | 2022 | Water Biology and Security2022，1，3： | 1 |
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