The ctenophore Mnemiopsis leidyi, ranking among the 100 most damaging bioinvaders in the world, is a major predator of zooplankton, known to alter the biodiversity and functioning of the ecosystems in which it has been introduced. This first survey on the trophic relationships of M. leidyi in a Mediterranean lagoon (Berre, South of France) was performed through stable isotope analyses. Carbon and nitrogen isotope composition was used (1) to determine the types of prey ingested by this ctenophore and (2) the influence of individual size on its isotope composition, and (3) to make assumptions to explore its trophic relationships with the native jellyfish Aurelia sp.. The two gelatinous species ingested mainly (79% to 97% of the diet) planktonic prey (copepods, cirriped nauplii, gastropod larvae and cladocerans), but also preyed upon benthic organisms (mainly harpacticoid copepods and the amphipod Monocorophium insidiosum) in lower proportions (2.5% to 21%). Size-related changes in M. leidyi diet were evidenced with an increase in trophic level and benthic prey consumption in the larger individuals. These two gelatinous organisms probably play an important and underestimated role in the benthic-pelagic coupling in coastal lagoons by transferring benthic organic matter to the pelagic food webs.

栉水母在Mnemiopsis水母，在世界100个最具破坏性bioinvaders中的排名，是浮游动物的主要天敌，已知改变生物多样性和它已经推出了生态系统的功能。通过稳定同位素分析，对地中海泻湖（法国南部的贝雷）中的雷迪氏菌的营养关系进行了首次调查。碳和氮的同位素组成用于（1）确定捕食该捕食体的猎物类型，（2）个体大小对其同位素组成的影响，以及（3）作出假设以探索其与天然水母的营养关系奥雷利亚这两种糊状物种主要（占日粮的79％至97％）被摄食浮游生物（足脚类动物，轮状无节幼体，腹足类幼体和锁骨类），但也捕食底栖生物（主要是类类拟足动物足纲动物和两栖类单壳食虫）。较低的比例（2.5％至21％）。较大个体的营养水平和底栖猎物消费量增加证明了莱比迪分食的大小相关变化。通过将底栖有机物转移到中上层食物网中，这两种凝胶状生物可能在沿海泻湖的底栖-上层耦合中起重要和被低估的作用。