Abrupt and Gradual Salt Application Mesocosm Experiment Zooplankton, Phytoplankton, Periphyton and Abiotic Data, Troy, NY, 2018.

Increasing chloride concentrations from road salt applications are an emerging threat to freshwater diversity in cold weather regions. Few studies have focused on how road salt affects freshwater biota and even fewer have focused on how the rate of exposure alters organism responses. We hypothesized that road salt concentrations delivered gradually would result in slower population declines and more rapid rebounds due to evolved tolerance. To test this hypothesis, we examined the responses of freshwater lake organisms to four environmentally relevant salt concentrations (100, 230, 860, and 1600 mg Cl−/L) that differed in application rate (abrupt vs. gradual). We used outdoor aquatic mesocosms containing zooplankton, filamentous algae, phytoplankton, periphyton, and macroinvertebrates. We found negative effects of road salt on zooplankton and macroinvertebrate abundance, but positive effects on phytoplankton and periphyton, likely resulting from reduced grazing. Only rarely did we detect a difference between abrupt vs gradual salt applications and the directions of those differences were not consistent. This affirms the need for additional research on how road salt pollution entering ecosystems at different frequencies and magnitudes will alter freshwater communities.

道路融雪盐施用引发的氯化物浓度升高，正成为寒冷气候区域淡水生物多样性的新兴威胁。目前鲜有研究探讨道路融雪盐对淡水生物群落的影响，而聚焦于暴露速率如何改变生物响应的研究更是少之又少。
我们提出假说：由于演化形成的耐受性，逐步施加的道路融雪盐浓度会导致种群衰退速度更缓、种群恢复速度更快。为验证该假说，我们检测了淡水湖泊生物对四种环境相关盐浓度（100、230、860及1600 mg Cl⁻/L）的响应，这些盐浓度的施加速率分为突发式与渐进式两类。
本实验采用包含浮游动物（zooplankton）、丝状藻类（filamentous algae）、浮游植物（phytoplankton）、周丛藻类（periphyton）以及大型无脊椎动物（macroinvertebrates）的室外水生中型实验生态系统（aquatic mesocosms）。
研究发现，道路融雪盐对浮游动物与大型无脊椎动物的丰度具有负面影响，但对浮游植物与周丛藻类则存在正向影响，这一现象大概率源于牧食压力的降低。我们仅极少能检测到突发式与渐进式盐施用之间的差异，且这类差异的方向并不统一。
上述结果证实，亟需开展更多相关研究，以探明以不同频率与强度进入生态系统的道路融雪盐污染，将如何改变淡水群落结构。