Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
Environ Pollut. 2017 Feb;221:159-167. doi: 10.1016/j.envpol.2016.11.060. Epub 2016 Dec 7.
The application of road deicing salts has led to the salinization of freshwater ecosystems in northern regions worldwide. Increased chloride concentrations in lakes, streams, ponds, and wetlands may negatively affect freshwater biota, potentially threatening ecosystem services. In an effort to reduce the effects of road salt, operators have increased the use of salt alternatives, yet we lack an understanding of how these deicers affect aquatic communities. We examined the direct and indirect effects of the most commonly used road salt (NaCl) and a proprietary salt mixture (NaCl, KCl, MgCl), at three environmentally relevant concentrations (150, 470, and 780 mg Cl/L) on freshwater wetland communities in combination with one of three biotic stressors (control, predator cues, and competitors). The communities contained periphyton, phytoplankton, zooplankton, and two tadpole species (American toads, Anaxyrus americanus; wood frogs, Lithobates sylvaticus). Overall, we found the two road salts did not interact with the natural stressors. Both salts decreased pH and reduced zooplankton abundance. The strong decrease in zooplankton abundance in the highest NaCl concentration caused a trophic cascade that resulted in increased phytoplankton abundance. The highest NaCl concentration also reduced toad activity. For the biotic stressors, predatory stress decreased whereas competitive stress increased the activity of both tadpole species. Wood frog survival, time to metamorphosis, and mass at metamorphosis all decreased under competitive stress whereas toad time to metamorphosis increased and mass at metamorphosis decreased. Road salts and biotic stressors can both affect freshwater communities, but their effects are not interactive.
道路融雪盐的应用导致了世界北方地区淡水生态系统的盐化。湖泊、溪流、池塘和湿地中增加的氯浓度可能会对淡水生物群产生负面影响，从而可能威胁到生态系统服务。为了减少道路盐的影响，操作人员增加了盐替代品的使用，但我们还不了解这些融雪剂如何影响水生群落。我们研究了最常用的道路盐（NaCl）和一种专有盐混合物（NaCl、KCl、MgCl）在三个环境相关浓度（150、470 和 780mg Cl/L）下，与三种生物胁迫（对照、捕食者线索和竞争者）中的一种结合对淡水湿地群落的直接和间接影响。这些群落包含周丛生物、浮游植物、浮游动物和两种蝌蚪物种（美洲蟾蜍，Anaxyrus americanus；林蛙，Lithobates sylvaticus）。总的来说，我们发现两种道路盐都没有与自然胁迫相互作用。两种盐都会降低 pH 值并减少浮游动物的数量。在最高 NaCl 浓度下，浮游动物数量的强烈减少导致了一个营养级联，导致浮游植物数量增加。最高 NaCl 浓度还降低了蟾蜍的活动。对于生物胁迫，捕食胁迫减少，而竞争胁迫增加了两种蝌蚪物种的活动。在竞争胁迫下，林蛙的存活率、变态时间和变态时的体重都降低了，而蟾蜍的变态时间增加，变态时的体重降低。道路盐和生物胁迫都会影响淡水群落，但它们的影响不是相互作用的。
