The phytoplankton compartment is particularly reactive to changes in nutrient concentration and is used as a quality indicator. Using a simple numerical approach, the response of emblematic harmful taxa from the eastern English Channel and southern North Sea to changes in nutrient inputs was studied. The method is based on a diachronic approach using averaged maxima over sliding periods of six years (1994–2018). This gave a final dataset containing pairs of points (number of years) for explained and explanatory variables. The temporal trajectory of the relationship between each pair of variables was then highlighted. Changes were represented as long-term trajectories that allowed a comparison to a reference/average situation. In addition, the relevance of the use of Phaeocystis globosa and the Pseudo-nitzchia complex as eutrophication species indicators was tested. Results showed a significant shift in the 2000s and different trajectories between diatoms and P. globosa abundances in response to changes in Dissolved Inorganic Nitrogen (DIN). The contrasting ecosystems under study reacted differently depending on the initial pressure. While a return to good ecological status does not seem feasible in the short term, it seems that these ecosystems were in an unstable intermediate state requiring continued efforts to reduce nutrient inputs.

中文翻译：

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与北英格兰南部东英吉利海峡中的营养压力相关的浮游植物生物量，球藻和硅藻的变化轨迹（包括Pseudo-nitzschia sp。）。

浮游植物隔室对营养物浓度的变化特别有反应，并用作质量指标。使用简单的数值方法，研究了来自英吉利海峡和北海南部的象征性有害生物分类对养分输入变化的响应。该方法基于历时方法，使用了六年（1994-2018年）滑动期内的平均最大值。这样就得到了一个最终的数据集，其中包含用于解释变量和解释变量的成对的点（年数）。然后突出显示了每对变量之间的关系的时间轨迹。变化被表示为允许与参考/平均情况进行比较的长期轨迹。此外，球囊藻的使用与测试了拟南芥属复合体作为富营养化物种的指标。结果表明，响应于溶解无机氮（DIN）的变化，硅藻和球形假单胞菌的 丰度在2000年代发生了显着变化，并且轨迹不同。根据初始压力，正在研究的对比生态系统的反应不同。虽然短期内恢复良好的生态状况似乎不可行，但似乎这些生态系统处于不稳定的中间状态，需要继续努力以减少养分投入。