Berlin University of Technology, Chair of Water Quality Control, Berlin, Germany.
Water Sci Technol. 2013;67(4):708-14. doi: 10.2166/wst.2012.583.
The process of reservoir eutrophication has been recognised as a central problem in tropical reservoir environmental quality. Effects of eutrophication are complex interactions involving a decrease in water quality, especially loss of aquatic biodiversity, occurrence of undesired species such as cyanobacteria with its cyanotoxins, mass development of macrophytes such as Egeria densa with its mechanical impact on turbines, and an increase in greenhouse gas emissions, mainly of methane. The eutrophication process can be described by the OECD critical load concept or related models. The phosphorus use efficiency is given by the Chl a-P - relationship, indicating eutrophic conditions by only 10 μg L(-1) P in Itaparica Reservoir, Brazil. Eutrophication of the reservoir is quantified for internal phosphorus sources (inflow, mineralisation of inundated soils and vegetation, net cage aquaculture) and external ones (agriculture, emissions of natural caatinga vegetation and rural communities) The actual internal P load is calculated to be 0.40 g m(-2) a(-1), and the critical P load is given with 1.20 g m(-2) a(-1). The external P load amounts about 1.16 g m(-2) a(-1) and thus exceeds the critical export rate of 7.1 kg km(-2) a(-1) by 50%, thus a bundling of measurements has to be considered when attempting to promote re-oligotrophication.
富营养化过程已被认为是热带水库环境质量的核心问题。富营养化的影响是复杂的相互作用，包括水质下降，特别是水生生物多样性的丧失，不希望出现的物种，如蓝藻及其产生的蓝藻毒素，大型水生植物如伊特帕里卡水库中的伊特帕里卡藻的大量繁殖，以及温室气体排放的增加，主要是甲烷。富营养化过程可以用经合组织的临界负荷概念或相关模型来描述。磷的利用效率由叶绿素 a-P 关系给出，表明伊特帕里卡水库的富营养化条件仅为 10μg L(-1) P。对水库的内部磷源（流入、淹没土壤和植被的矿化、网箱水产养殖）和外部磷源（农业、天然 caatinga 植被和农村社区的排放）进行了富营养化量化。实际的内部 P 负荷被计算为 0.40 g m(-2) a(-1)，而临界 P 负荷为 1.20 g m(-2) a(-1)。外部 P 负荷约为 1.16 g m(-2) a(-1)，因此超过了 7.1 kg km(-2) a(-1)的临界输出率的 50%，因此在试图促进再寡营养化时，必须考虑综合测量。
