Coastal environments are affected by multiple pressures resulting from anthropogenic activities, among which organic enrichment (C_org) is particularly important. Foraminiferal communities react to organic enrichment by changes in community structure (density, diversity, species composition) and behaviour (metabolism, feeding strategy, reproduction, mortality, etc.). A number of biotic indices based on foraminiferal faunas have been developed to measure the impact of anthropogenic organic enrichment on the ecological quality of marine soft bottom environments. However, the multiple origins of organic matter and its diffuse dispersion make it difficult to clearly identify enrichment gradients and the community changes along them. In this context, marine disposals of activated sewage sludge, which represent localised point sources of organic matter, offer the possibility to study faunal successions along a well-developed stress gradient. The main objectives of this study are to test 1) the ecological assignments of Mediterranean foraminifera species as recently proposed by Jorissen et al. (2018), and 2) two biotic indices, based on groups of indicator species, developed in the Mediterranean Sea, TSI-Med and Foram-AMBI, along such an organic matter gradient, resulting from a sewage outlet off the Israeli coast, south of Tel-Aviv. Along the studied organic enrichment gradient, Caronia silvestrii dominated the foraminiferal faunas in the most severely impacted zone. Further away from the sewage outlet, faunas were characterised by the dominance of Ammonia tepida. Finally, in the least affected area, farthest away from the sewage outlet, Leptohalysis scottii was the dominant taxon. Our observations strongly contrast with earlier assignments of C. silvestrii and L. scottii to ecological groups III (3rd order opportunists) and V (1st order opportunists), respectively (Jorissen et al., 2018). This discrepancy strongly suggests that additional studies are urgently needed to better characterise the ecological strategies of major ecological index species. When, as we propose here, L. scottii is not included in the group of stress-tolerant taxa for TSI-Med, and C. silvestrii and L. scottii are reassigned respectively to ecological groups V and III for Foram-AMBI, both tested indices clearly show the decreasing impact of organic enrichment with greater distance from the sewage outlet. These species reassignments underline the need to distinguish between stress-tolerant and opportunistic taxa, which do not give the same information about environmental quality.

沿海环境受到人为活动造成的多种压力的影响，其中包括有机富集（C _org）尤其重要。有孔虫群落通过群落结构（密度，多样性，物种组成）和行为（代谢，喂养策略，繁殖，死亡率等）的变化对有机物富集做出反应。已经开发了许多基于有孔虫动物群的生物指标来衡量人为有机物富集对海洋软底环境生态质量的影响。但是，有机物的多种起源及其分散的分散性使得难以清楚地识别出富集梯度和沿它们的群落变化。在这种情况下，代表局部有机物源的活性污泥的海洋处置，为研究沿高度发达的应力梯度的动物演替提供了可能性。这项研究的主要目的是测试1）Jorissen等人最近提出的地中海有孔虫物种的生态学分配。（2018）和2）在地中海沿岸，TSI-Med和Foram-AMBI上建立了基于指示物种组的两个生物指数，其有机物梯度来自以色列南部沿海的污水出口特拉维夫。沿着研究的有机富集梯度，Caronia silvestrii在受影响最严重的地区以有孔虫动物为主。远离污水出口的地方，动物区系以氨纶为特征。最后，在受影响最小的地区，离污水出口最远的地方，斯科特Leptohalysis是主要的分类群。我们的观察结果与C. silvestrii和L. scottii早期被分别划为生态学组III（三阶机会主义者）和V（一阶机会主义者）形成鲜明对比（Jorissen et al。，2018）。这种差异强烈表明，迫切需要进行其他研究以更好地表征主要生态指数物种的生态策略。正如我们在此建议的，对于TSI-Med，L。scottii不包括在耐应力类群中，而Foram-AMBI的C. silvestrii和L. scottii分别重新分配到了生态组V和III，这两个测试指标清楚地表明，有机浓缩，距排污口的距离更大。这些物种的重新分配突显了区分压力承受的分类单元和机会分类单元的需要，这些分类单元没有提供有关环境质量的相同信息。