Causes and consequences of contaminant-induced chemosensory deficits in aquatic animals

水生动物依靠化学感官信息来调节一系列对生存至关重要的行为。例如，化学感官刺激可以告知动物被捕食的风险、食物或迁徙路线的位置，以及潜在配偶的适宜性。环境污染物，如金属、杀虫剂、碳氢化合物、药品和个人护理产品(PPCP)会损害嗅觉，导致不适应行为缺陷。未能成功评估捕食风险、寻找食物或识别潜在配偶可能会导致生态死亡。因此，了解导致污染物诱导的化学感觉损害的过程对于评估生态风险和预测不利的生态后果至关重要。 尽管我们已经确定了一些污染物可以损害淡水动物的嗅觉调节行为，但我们仍然对这些影响的机制或它们的生态后果知之甚少。此外，几乎没有研究涉及多种应激源对化学感觉功能和行为的混杂影响，例如污染物和气候变化的混合物。这项研究的目的是了解污染物诱导的嗅觉损伤作为预测不良适应行为反应的一种手段的机制本质，以及这些影响是如何被多种应激源改变的。 将选择代表典型水生生态系统的几个级别的物种(例如，中上层浮游动物、底栖无脊椎动物和鱼类)。在第一阶段，将使用既定的神经生理学和行为技术来确定化学感觉阈值。然后，这些阈值将通过暴露于一系列常见环境污染物中的一种而受到挑战，例如金属、碳氢化合物、杀虫剂或PPCPs。化学感觉和行为反应将使用基因表达分析、组织学、电嗅觉(EOG)和行为视频跟踪来表征。二次应激源将在第二阶段期间应用于第一阶段暴露情景，如温度升高或盐度升高。在第三阶段，将从自然系统收集动物，包括清洁和受污染的水体，并以其化学感觉或行为功能为特征。 这项研究结合了实验室和现场技术，使用了代表大多数淡水生态系统典型的几个营养级别的一系列生物体，以确定与变化的环境相关的多种应激源如何影响化学感觉功能和行为。归根结底，一个主要目标是确定淡水动物能够在多大程度上适应不断变化的环境条件，将化学传感功能和行为作为生物效应的敏感指标。

Aquatic animals rely on chemosensory information to mediate a range of behaviours that are vital for survival. For example, chemosensory stimuli can inform an animal about the risk of predation, the location of food or migratory routes, and the appropriateness of a potential mate. Environmental contaminants such as metals, pesticides, hydrocarbons, and pharmaceuticals and personal care products (PPCPs) can impair olfaction leading to maladaptive behavioural deficits. Failure to successfully evaluate the risk of predation, find food, or identify potential mates can lead to ecological death.' Consequently, understanding the processes that lead to contaminant-induced chemosensory impairment is critical to evaluating ecological risk and predicting adverse ecological outcomes. Although we have identified a number of contaminants that can impair olfactory-mediated behaviours in freshwater animals, we still have very little understanding about the mechanisms of those effects, or of their ecological consequences. Moreover, almost no research has addressed the confounding influence of multiple stressors, such as mixtures of contaminants and climate change, on chemosensory function and behaviour. The purpose of this research program is to understand the mechanistic nature of contaminant-induced olfactory impairment as a means to predict maladaptive behavioural responses, and how those effects are modified by multiple stressors. Species will be selected to represent several levels of a typical aquatic ecosystem (e.g., pelagic zooplankton, benthic invertebrates, and fish). During the first phase, chemosensory thresholds will be determined using established neurophysiological and behavioural techniques. These thresholds will then be challenged by exposure to one of a number of common environmental contaminants, such as metals, hydrocarbons, pesticides, or PPCPs. Chemosensory and behavioural responses will be characterized using gene expression analysis, histology, electro-olfactography (EOG), and behavioural video-tracking. A secondary stressor will be applied to Phase 1 exposure scenarios during the second phase, such as elevated temperature or salinity. During the third phase, animals will be collected from natural systems, including both clean and contaminated water bodies, and characterized for their chemosensory or behavioural function. Together, this research combines both laboratory and field techniques using a range of organisms representing several trophic levels typical of most freshwater ecosystems, in order to determine how multiple stressors related to changing environments affect chemosensory function and behaviour. Ultimately, a major objective is to determine the extent to which freshwater animals can adapt to changing environmental conditions, using chemosensory function and behaviour as a sensitive indicator of biological effect.