title: Investigation of road salts and biotic stressors on freshwater wetland communities.
abstract: 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, MgCl2), 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.
authors.affiliation: Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA. Electronic address: jonesd11@rpi.edu.
authors.forename: Devin K
authors.initials: DK
authors.lastname: Jones
authors.affiliation: Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Mattes
authors.affiliation: Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
authors.forename: William D
authors.initials: WD
authors.lastname: Hintz
authors.affiliation: Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Schuler
authors.affiliation: Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
authors.forename: Aaron B
authors.initials: AB
authors.lastname: Stoler
authors.affiliation: Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
authors.forename: Lovisa A
authors.initials: LA
authors.lastname: Lind
authors.affiliation: Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
authors.forename: Reilly O
authors.initials: RO
authors.lastname: Cooper
authors.affiliation: Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
authors.forename: Rick A
authors.initials: RA
authors.lastname: Relyea
mesh_terms: D000818:Animals; D002025:Bufonidae; D017753:Ecosystem; D004784:Environmental Monitoring; D005618:Fresh Water; D007814:Larva / Q000187:drug effects; D015636:Magnesium Chloride; D008675:Metamorphosis, Biological / Q000187:drug effects; D010839:Phytoplankton / Q000187:drug effects; D061005:Ponds; D011898:Ranidae; D012492:Salts / Q000032:analysis / Q000633:toxicity*; D012965:Sodium Chloride; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*; D053833:Wetlands; D015048:Zooplankton / Q000187:drug effects
chemical_list: D012492:Salts; D014874:Water Pollutants, Chemical; D015636:Magnesium Chloride; D012965:Sodium Chloride
keywords: Cladoceran; Copepod; Ecotoxicology; Novel environment; Species interactions; Tolerance