Increasing chloride concentrations threaten freshwater zooplankton. We questioned the protectiveness of the Canadian Water Quality Guideline for chloride because it is based on individual species studied under laboratory conditions and does not account for potential interactive factors, such as nutrient concentration. We exposed plankton communities to 30 chloride concentration increments for 6 weeks, crossed with either ambient or high nutrient treatments. Total zooplankton abundance, biomass, and richness declined with increasing chloride, with losses observed below the Canadian Water Quality Guideline. Nutrients did not affect the impact of chloride on zooplankton. Phytoplankton and protist responses varied by nutrient level. Under low nutrients, phytoplankton and protist abundance, biomass, and richness increased with chloride. Under high nutrients, phytoplankton and protist abundance and biomass were unaffected while richness decreased with chloride. These results indicate that current water quality guidelines do not sufficiently protect plankton and that nutrient context may alter phytoplankton and protist response.

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氯化物和营养物质对淡水浮游生物群落的影响

不断增加的氯化物浓度威胁着淡水浮游动物。我们质疑加拿大​​水质指南对氯化物的保护性，因为它是基于在实验室条件下研究的个别物种，没有考虑潜在的相互作用因素，例如营养浓度。我们将浮游生物群落暴露于 30 个氯化物浓度增量 6 周，并与环境或高营养处理交叉。浮游动物的总丰度、生物量和丰富度随着氯化物的增加而下降，观察到的损失低于加拿大水质指南。营养物不影响氯化物对浮游动物的影响。浮游植物和原生生物的反应因营养水平而异。在低营养条件下，浮游植物和原生生物的丰度、生物量和丰富度随着氯化物的增加而增加。在高营养条件下，浮游植物和原生生物的丰度和生物量不受影响，而丰富度随氯化物而降低。这些结果表明，目前的水质指南不足以保护浮游生物，营养环境可能会改变浮游植物和原生生物的反应。