Water quality and contaminants have been frequently identified as critical stressors for freshwater mussels, many species of which are highly imperiled throughout North America and the world. Nutrient pollution, specifically nitrate, has become one of the most prevalent causes of water quality degradation globally, with increasing anthropogenic input from suburban and agricultural runoff, municipal wastewater, and industrial waste. Nitrate acute toxicity is generally low for aquatic species, but the potential effects of nitrate exposure are largely unknown for freshwater mussels, particularly during the parasitic stage of their complex lifecycle. Therefore, this study was designed to determine the effects of short-term nitrate exposure at environmentally relevant concentrations on juvenile production in two freshwater mussel species. Lampsilis siliquoidea and L. fasciola glochidia were exposed to nitrate (0, 11, or 56 mg NO₃-N/L) for 24 h before inoculation on a primary host, Largemouth Bass (Micropterus salmoides). Glochidia attachment, metamorphosis success, and total number of juveniles produced were monitored on individual fish. Exposure of L. siliquoidea glochidia to 56 mg NO₃-N/L nitrate resulted in a significant (p = 0.02) 35% reduction of total juveniles produced, a combined result of moderate decreases in both glochidia attachment and metamorphosis success. A similar trend (28% reduction; p = 0.06) was evident with 11 mg NO₃-N/L. No effects were apparent for L. fasciola, suggesting species-specific differences in responses even among closely related species. These results are the first to suggest that glochidia exposure to nitrate may adversely affect juvenile recruitment in some species. Findings from these studies are important for improving characterization of the hazards of nitrate pollution to aquatic life and this work will help better define the role of water quality in assessing habitat suitability for mussel conservation efforts.

水质和污染物经常被认为是淡水贻贝的重要压力源，在整个北美和世界范围内，淡水贻贝的许多物种受到严重危害。营养物质的污染，特别是硝酸盐，已成为全球水质恶化的最普遍原因之一，郊区和农业径流，城市废水和工业废物的人为投入也在增加。硝酸盐对水生物种的急性毒性通常较低，但对于淡水贻贝而言，硝酸盐暴露的潜在影响在很大程度上尚不清楚，尤其是在其复杂生命周期的寄生阶段。因此，本研究旨在确定环境相关浓度下短期硝酸盐暴露对两种淡水贻贝物种的幼鱼生产的影响。在接种到主要寄主大口黑鲈（大嘴鲈）上之前，先将兰斯兰丝吸虫和格氏乳杆菌（L. fasciola glochidia）暴露于硝酸盐（0、11或56 mg NO ₃ -N / L）中24小时。在个别鱼类上监测了glochidia的附着，变态成功和幼鱼总数。球状镰刀菌暴露于56 mg NO ₃ -N / L硝酸盐会使所生产的幼鱼数量大幅减少（p = 0.02）35％，这是球状杆菌附着和变态成功率适度下降的综合结果。11 mg NO ₃ -N / L时也出现类似趋势（减少28％； p = 0.06）。对于fasciola L. fasciola没有明显影响，这表明即使在密切相关的物种之间，物种特异性的反应差异也是如此。这些结果首次表明，芦荟暴露于硝酸盐可能会对某些物种的少年募集产生不利影响。这些研究的发现对于改善硝酸盐污染对水生生物的危害的表征非常重要，这项工作将有助于更好地确定水质在评估贻贝保护工作的生境适宜性中的作用。