Devlin Michelle, Best Mike, Coates Deborah, Bresnan Eileen, O'Boyle Shane, Park Richard, Silke Joe, Cusack Caroline, Skeats Joe
Centre for Environment, Fisheries and Aquaculture Science, Pakefield Rd., Lowestoft NR3 3EJ, UK.
Mar Pollut Bull. 2007;55(1-6):91-103. doi: 10.1016/j.marpolbul.2006.09.018. Epub 2006 Oct 24.
This paper presents a description of three of the proposed phytoplankton indices under investigation as part of a classification framework for UK and ROI marine waters. The three indices proposed for the classification process are (i) phytoplankton biomass measured as chlorophyll, (ii) the frequency of elevated phytoplankton counts measuring individual species and total cell counts and (iii) Seasonal progression of phytoplankton functional groups through the year. Phytoplankton biomass is calculated by a 90th percentile measurement of chlorophyll over the growing season (April to September) compared to a predetermined reference value. Calculation of functional groups and cell counts are taken as proportional counts derived from the presence of the indicator species or group as compared to the total phytoplankton count. Initial boundary conditions for the assessment of high/good status were tested for each index. Chlorophyll reference conditions were taken from thresholds developed for previous EU directives with the setting of offshore concentrations as a reference condition. Thresholds for elevated counts of phytoplankton taxa were taken from previous EU assessments describing counts that could be impact negatively on the environment. Reference seasonal growth curves are established using phytoplankton counts from "high status" waterbodies. To test the preliminary boundaries for each index, a risk assessment integrating nutrient enrichment and susceptibility for coastal and transitional waters was carried out to identify WFD waterbodies in England and Wales at different levels of risk. Waterbodies assessed as having low or medium risk from nutrient enrichment were identified as type 1 and type 2 waterbodies, and waterbodies assessed as high risk were identified as type 3 waterbodies. Phytoplankton data was extracted from the risk assigned waterbodies and applied to each phytoplankton index to test the robustness of the preliminary classification ranges for each phytoplankton index.
本文介绍了作为英国和爱尔兰共和国沿海水域分类框架一部分正在研究的三种拟议浮游植物指数。为分类过程提出的三个指数分别是：（i）以叶绿素衡量的浮游植物生物量；（ii）测量单个物种和总细胞计数的浮游植物数量升高的频率；（iii）浮游植物功能群全年的季节性变化。浮游植物生物量通过在生长季节（4月至9月）对叶绿素进行第90百分位数测量，并与预先确定的参考值进行比较来计算。功能群和细胞计数的计算是根据指示物种或类群的存在与浮游植物总数的比例计数得出的。对每个指数测试了评估高/良好状态的初始边界条件。叶绿素参考条件取自为先前欧盟指令制定的阈值，并将近海浓度设定为参考条件。浮游植物分类群数量升高的阈值取自先前欧盟的评估，这些评估描述了可能对环境产生负面影响的数量。参考季节性生长曲线是使用来自“高状态”水体的浮游植物计数建立的。为了测试每个指数的初步边界，对沿海和过渡水域进行了一项综合营养物富集和敏感性的风险评估，以识别英格兰和威尔士处于不同风险水平的《水框架指令》水体。被评估为营养物富集低风险或中等风险的水体被确定为1类和2类水体，被评估为高风险的水体被确定为3类水体。从分配了风险的水体中提取浮游植物数据，并将其应用于每个浮游植物指数，以测试每个浮游植物指数初步分类范围的稳健性。
