Runoff containing road salt (sodium chloride, NaCl) causes the salinization of inland freshwaters, with potentially severe impacts on aquatic species. We performed a mesocosm experiment to test the effects of salinization on plankton community structure in an oligotrophic mountain lake with a limited history of elevated salt concentrations. We exposed plankton communities to a gradient of 30 salt concentrations ranging from 1 to 2900 Cl⁻ mg L⁻¹ for 6 weeks. Adding salt increased zooplankton biomass at concentrations < 500 mg Cl⁻ L⁻¹ while reducing phytoplankton biomass. Zooplankton biomass declined precipitously at higher concentrations, with phytoplankton biomass showing a mirror image increase. The initial increase in zooplankton biomass with salt addition suggests that zooplankton are salt-limited at low ionic concentrations. Additionally, the inverse response of zooplankton and phytoplankton suggests that salinity mainly affects phytoplankton biomass via changes in top-down regulation by grazers.

中文翻译：

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淡水盐碱化对内华达山脉浮游生物群落的级联效应

含有路盐（氯化钠、NaCl）的径流导致内陆淡水盐碱化，可能对水生物种造成严重影响。我们进行了一个中观实验，以测试盐碱化对盐浓度升高历史有限的贫营养高山湖泊中浮游生物群落结构的影响。我们将浮游生物群落暴露于 1 至 2900 Cl ⁻  mg L ⁻¹的 30 种盐浓度梯度中，持续 6 周。在浓度 < 500 mg Cl ⁻  L ^{−1时，添加盐会增加浮游动物生物量}同时减少浮游植物生物量。浮游动物生物量在较高浓度下急剧下降，浮游植物生物量呈镜像增加。添加盐后浮游动物生物量的初始增加表明浮游动物在低离子浓度下受盐限制。此外，浮游动物和浮游植物的逆反应表明盐度主要通过食草动物自上而下调节的变化影响浮游植物生物量。