Urban stormwater runoff negatively impacts lateral line development in larval zebrafish and salmon embryos Scientific Reports

After a storm, water often runs off of impervious urban surfaces directly into aquatic ecosystems. This stormwater runoff is a cocktail of toxicants that have serious effects on the ecological integrity of aquatic habitats. Zebrafish that develop in stormwater runoff suffer from cardiovascular toxicity and impaired growth, but the effects of stormwater on fish sensory systems are not understood. Our study investigated the effect of stormwater on hair cells of the lateral line in larval zebrafish and coho salmon. Our results showed that although toxicants in stormwater did not kill zebrafish hair cells, these cells did experience damage. Zebrafish developing in stormwater also experienced impaired growth, fewer neuromasts in the lateral line, and fewer hair cells per neuromast. A similar reduction in neuromast number was observed in coho salmon reared in stormwater. Bioretention treatment, intended to filter out harmful constituents of stormwater, rescued the lateral line defects in zebrafish but not in coho salmon, suggesting that not all of the harmful constituents were removed by the filtration media and that salmonids are particularly sensitive to aquatic toxicants. Collectively, these data demonstrate that sub-lethal exposure to stormwater runoff negatively impacts a fish sensory system, which may have consequences for organismal fitness. Grant no. NA14OAR4170078

风暴过后，雨水常会经由不透水的城市地表直接汇入水生生态系统。此类雨水径流实为混合有毒物质的复合体系，会对水生生境的生态完整性造成严重损害。在雨水径流环境中发育的斑马鱼（Zebrafish）会出现心血管毒性与生长受阻的症状，但目前学界尚未明确雨水径流对鱼类感觉系统的具体影响。本研究探究了雨水径流对斑马鱼（Zebrafish）幼体及银大麻哈鱼（coho salmon）侧线（lateral line）毛细胞（hair cells）的影响。研究结果显示，尽管雨水径流中的有毒物质并未导致斑马鱼毛细胞死亡，但此类细胞确实出现了损伤。在雨水径流中发育的斑马鱼还表现出生长受阻、侧线神经丘（neuromasts）数量减少，以及每个神经丘内毛细胞数目降低的现象。在雨水径流中饲养的银大麻哈鱼同样观察到神经丘数量减少的情况。旨在滤除雨水径流有害成分的生物滞留处理（Bioretention treatment）可修复斑马鱼的侧线缺陷，但无法改善银大麻哈鱼的相关异常，这表明滤料并未完全去除雨水径流中的有害成分，且鲑科鱼类（salmonids）对水生有毒物质尤为敏感。综合而言，本研究数据证实，经亚致死暴露（sub-lethal exposure）于雨水径流会对鱼类的感觉系统造成负面影响，这可能会对个体适合度（organismal fitness）产生不利后果。资助编号：NA14OAR4170078