Université de Lorraine, CNRS, LIEC, F-57000 Metz, France; LTSER-Zone Atelier Moselle, F-57000 Metz, France.
Université de Lorraine, CNRS, LIEC, F-57000 Metz, France; Université de Toulouse, Laboratoire Ecologie Fonctionnelle et Environnement UMR 5245 CNRS, Toulouse, France.
Water Res. 2022 Jun 1;216:118325. doi: 10.1016/j.watres.2022.118325. Epub 2022 Mar 19.
Shallow lakes provide essential ecological and environmental services but are exposed to multiple stressors, including agricultural runoff (ARO) and climate warming, which may act on different target receptors disrupting their normal functioning. We performed a microcosm experiment to determine the individual and combined effects of three stressors-pesticides, nitrate and climate warming-on two trophic levels representative of communities found in shallow lakes. We used three submerged macrophyte species (Myriophyllum spicatum, Potamogeton perfoliatus, Elodea nuttallii), eight benthic or pelagic microalgal species and three primary consumer species (Daphnia magna, Lymnaea stagnalis, Dreissena polymorpha) with different feeding preferences for benthic and pelagic primary producers. Eight different treatments consisted of a control, only nitrate, a pesticide cocktail, and a combination of nitrate and pesticides representing ARO, each replicated at ambient temperature and +3.5°C, mimicking climate warming. Pesticides negatively affected all functional groups except phytoplankton, which increased. Warming and nitrate modified these effects. Strong but opposite pesticide and warming effects on Myriophyllum drove the response of the total macrophyte biomass. Nitrate significantly suppressed Myriophyllum final biomass, but not overall macrophyte and microalgal biomass. Nitrate and pesticides in combination caused a macrophyte decline, and the system tipped towards phytoplankton dominance. Strong synergistic or even reversed stressor interaction effects were observed for macrophytes or periphyton. We emphasize the need for more complex community- and ecosystem-level studies incorporating multiple stressor scenarios to define safe operating spaces.
浅水湖泊提供了重要的生态和环境服务，但它们面临着多种胁迫，包括农业径流 (ARO) 和气候变暖，这些因素可能会对不同的目标受体产生影响，破坏它们的正常功能。我们进行了一个微宇宙实验，以确定三种胁迫因素——农药、硝酸盐和气候变暖——对两种代表浅水湖泊群落的营养层次的单独和联合影响。我们使用了三种沉水植物物种（狐尾藻、菹草、水蕴草）、八种底栖或浮游微藻物种和三种初级消费者物种（大型溞、圆田螺、多刺裸鲤），它们对底栖和浮游初级生产者有不同的摄食偏好。八种不同的处理包括对照、仅硝酸盐、农药混合物以及代表农业径流的硝酸盐和农药组合，每种处理在环境温度和+3.5°C 下重复，模拟气候变暖。农药除了浮游植物外，对所有功能群都有负面影响，浮游植物增加了。变暖和硝酸盐改变了这些影响。农药和变暖对狐尾藻的强烈但相反的影响驱动了总大型植物生物量的响应。硝酸盐显著抑制了狐尾藻的最终生物量，但不影响大型植物和微藻的总生物量。硝酸盐和农药的组合导致大型植物减少，系统向浮游植物优势倾斜。对于大型植物或周丛生物，我们观察到了强烈的协同作用，甚至是相反的胁迫相互作用效应。我们强调需要进行更复杂的群落和生态系统水平的研究，纳入多种胁迫情景，以确定安全运行空间。
