This document summarizes two studies on the effects of road salt (NaCl) on amphibian populations. Field studies found that salt concentrations were negatively correlated with distance from roads and species richness. Laboratory experiments showed high mortality rates in wood frogs and spotted salamanders exposed to environmentally relevant salt concentrations. Chronic exposure caused physiological changes and decreased time to metamorphosis. The studies conclude that road salt exposure can negatively impact amphibian community structure by excluding salt-sensitive species.

1. The Effects of Road Salt (NaCl) on the Survivorship of Two Vernal Pool-Breeding Amphibians: The Wood Frog (Rana sylvatica) and Spotted Salamander (Ambystoma maculatum) Denise M. Roth Baldwin-Wallace College Department of Biology May 1, 2009

2. “Why should we care if they all die? They are gross anyway!” -BW student

3. Well… Good Question http://www.fishingfury.com/wp-content/uploads/2008/05/record-halibut.jpg

4. Algae http://www.waterencyclopedia.com/images/wsci_01_img0017.jpg http://doctorswithoutborders.org/images/news/malaria/malaria_header_550x367.jpg

5. So… What is going on? E.O. Wilson says: Habitat destruction Invasive species Population Pollution Over-harvesting http://farm1.static.flickr.com/123/330811704_282ee8a597.jpg

6. What is a Vernal Pool?? Temporary Form from melting snow and spring rains Dry mid to late summer Unpredictable Naturally occurring Shallow (4ft > deep) Impermeable substrate on bottom Free of predatory fish http://www.fs.fed.us/ne/amherst/images/vernalpool.jpg

7. Vernal Pool (cont.) Contain one or more of four indicator species Blue-spotted Salamanders (Ambystoma laterale) Fairy Shrimp (Anostraca) Wood Frog (Rana sylvatica) Spotted Salamander (Ambystoma maculatum) http://www.umaine.edu/wetlands/VPecology.htm

8. Wood Frog (Rana sylvatica) http://www.nae.usace.army.mil/recreati/uvd/UVD_amphibians/uvdwoodfrog.html http://wpcontent.answers.com/wikipedia/commons/7/7f/Rana-sylvatica_Range.gif

9. Wood Frog: Reproduction

10. Spotted Salamander (Ambystoma maculatum) http://www.vernalpool.org/images/21_ys_a.jpg http://www.grizzlyrun.com/Files/Images/Image_Gallery/spotted_salamander_Range.gif

11. Spotted Salamander: Reproduction

12. Egg Masses http://www.vernalpool.org/images/115-js-ys-wf.jpg

13. Salts as De-Icing Agents NaCl most common 5 million tons/yr in Canada 10-15 million tons/yr in US (Environment Canada Website) Lower freezing point of water! melts at lower temperatures Cheap ~$30/ton Effective Above ~ 15˚F

14. Effects of road de-icing salt (NaCl) on larval wood frogs (Rana sylvatica) DomenicoSanzo, Stephen J. Hecnar 2003 Environmental pollution

15. Objective Determine the effect of road salts, if any, on amphibians at environmentally relevant field concentrations Hypothesis: Road salts have a negative effect on amphibians.

16. Study Location Thunder Bay, Canada Lakehead University Environmental Laboratories http://www.lib.utexas.edu/maps/united_states/united_states_wall_2002_us.jpg

17. Field Concentrations Water analysis of 59 wetlands 2 water samples from opposite ends of each Analyzed in university lab Expected to see: Salt concentrations negatively correlated with increasing distance of a wetland from the nearest road Negative correlation between salt concentrations and species richness

18. Results: Field Concentration Range in NaCl from 0.39 to 1030.00 mg/l Seawater ~ 3.5% NaCl ( 19,400 mg/l) NaCl decreased with increasing distance from nearest road Species richness negatively correlated with NaCl and positively correlated with increasing distance to nearest road

19. Materials and Methods:Acute Toxicity Experiment time 96 hours

20. Methods cont. Death defined: “… no response to continued prodding with a glass rod.”

21. Results: Acute Toxicity

22. Results: Acute Toxicity (cont.)

23. Methods:Chronic Toxicity 30 tadpoles to each tank

24. Methods (cont.)

25. Results: Chronic Toxicity

26. Mean time to Morph vs. Chronic Treatment concentrations

27. Discussion

28. Conclusions Road salts have a negative impact Chloride in roadside pools much higher than woodlands Supports hypothesis Species richness negatively correlated with NaCl concentrations Fewer tadpoles metamorphose with higher concentrations Does this relate to other amphibians? and is the evidence conclusive?

29. Sara J. Collins, Ronald W. Russell 2006 Environmental pollution Toxicity of road salt to Nova Scotia amphibians

30. Objective “…examine how chloride concentrations in ponds, due to application of road salt, influence amphibian community structure and richness in roadside wetlands of Nova Scotia.” Hypothesis: Elevated Chloride concentrations affect amphibian populations

31. Nova Scotia April-Sept. 2006 26 ponds http://www.lib.utexas.edu/maps/united_states/united_states_wall_2002_us.jpg

32. Field Methods Water samples collected for lab analysis May-September

33. Chloride Concentrations

34. Results: Species Richness

35. Methods:Acute Toxicity Larvae of 5 amphibian species: Spotted Salamander Spring Peeper Wood Frog Green Frog American Toad

36. Methods (cont.)

37. Species Abundance vs. Chloride Concentrations

38. Results: Acute Toxicity Tests

39. Conclusions Spotted Salamanders and Wood Frogs were most sensitive to NaCl Road salt concentrations affected community structure Sensitive species were absent from high chloride concentrated ponds Acute toxicity results supported field observations Behavioral changes could result in reduction of species fitness

40. Interpretation Exposure to road salts can affect amphibian community structure and species richness by excluding salt-sensitive species from high chloride environments

41. Overall Conclusions At environmentally realistic concentrations, road salt caused physiological issues and decreased survivorship in amphibians. Acute toxicity results of both studies showed high rates of mortality Chronic exposure caused physiological differences

42. This is not new information! In 1859 Charles Darwin noted that “nearly all amphibians and their spawn were killed by sea water” (Origin of Species)

43. http://kornorstone.com/db3/00225/kornorstone.com/_uimages/BubbleBoy1.jpg

44. Alternatives Potassium Acetate -76˚F $700-800/ton Less toxic; less corrosive; can cause %50 solution irritation if inhaled

45. Future Studies Why do higher salt concentrations cause tadpoles to metamorphose faster? Why was there a spike in survival from 7500-9000 mg/l? Possible mutagenic effects of developing tadpoles Effects of other road salts on these two species Reasons for salt tolerance seen in the American Toad Long term effects on community structure How chemical runoff affects people

46. “We now face an extinction episode on this planet comparable to that which marked the end of the dinosaurs about 65 million years ago”(Planet Earth Episode 1)

48. Dr. Barratt

50. ParentsFriends… all of you!

51. Questions?

52. Function of Chloride Chloride: membrane function and water absorption In the body reacts with potassium Helps maintain osmotic equilibrium by creating concentration gradient through ATP either goes in to the cell or leaves the cell ~ based on solute concentration in the water vs. solute in the cell Moves from high to low concentrations Helps maintain pH Kidney function: co-transport proteins Na+, K+, Cl -