INRAE, UR EABX, 33612, Cestas, France.
Pôle R&D ECLA, Le Bourget-du-Lac, France.
Environ Monit Assess. 2023 Sep 13;195(10):1202. doi: 10.1007/s10661-023-11855-w.
Eutrophication impairs lake ecosystems at a global scale. In this context, as benthic microalgae are well-established warnings for a large range of stressors, particularly nutrient enrichment, the Water Framework Directive required the development of diatom-based methods to monitor lake eutrophication. Here, we present the diatom-based index we developed for French lakes, named IBDL (Indice Biologique Diatomées en Lacs). Data were collected in 93 lakes from 2015 to 2020. A challenge arose from the discontinuous pressure gradient of our dataset, especially the low number of nutrient-impacted lakes. To analyze the data we opted for the so-called "Threshold Indicator Taxa ANalysis" method, which makes it possible to determine a list of "alert taxa." We obtained a multimetric index based on specific pressure gradients (Kjeldahl nitrogen, suspended matter, biological oxygen demand, and total phosphorous). Considering the European intercalibration process, the very good correlation between IBDL and the common metric (R from 0.52 to 0.87 according to the lake alkalinity type) makes us very confident in our ability to match future IBDL quality thresholds with European standards. The IBDL proved at last to be particularly relevant as it has a twofold interest: an excellent relationship with total phosphorus (R from 0.63 to 0.83 according to the lake alkalinity type) and a possible application to any lake metatype. Its complementarity with macrophyte-based indices moreover justifies the use of at least two primary producer components for lake ecological status classification.
富营养化会对全球范围内的湖泊生态系统造成损害。在这种情况下，由于底栖微藻是广泛存在的各种胁迫因素的良好预警指标，尤其是营养物质富集会对其造成影响，因此《水框架指令》要求开发基于硅藻的方法来监测湖泊富营养化。在此，我们提出了我们为法国湖泊开发的基于硅藻的指数，命名为 IBDL（湖泊硅藻生物指数）。该数据于 2015 年至 2020 年期间在 93 个湖泊中收集。我们的数据集中存在一个挑战，即压力梯度不连续，特别是营养物质影响的湖泊数量较少。为了分析这些数据，我们选择了所谓的“阈值指示分类分析”方法，该方法可以确定一系列“预警分类群”。我们基于特定的压力梯度（凯氏氮、悬浮物、生化需氧量和总磷）获得了一个多指标指数。考虑到欧洲的相互校准过程，IBDL 与常用指标（根据湖泊碱度类型，R 值从 0.52 到 0.87）之间非常好的相关性使我们对未来匹配 IBDL 质量阈值与欧洲标准的能力非常有信心。IBDL 被证明是特别相关的，因为它有两个优点：与总磷有极好的关系（根据湖泊碱度类型，R 值从 0.63 到 0.83），并且可能适用于任何湖泊类型。此外，它与大型植物基指数的互补性证明了至少使用两种初级生产者成分来对湖泊生态状况进行分类是合理的。
