I am enrolled in a Creative Inquiry course at Clemson University in which the question asked in the creative inquiry I am apart of has to do with is how the movement of human populations to a less developed location (ex-urbanization) effects salamanders. I specifically have questioned if salamander sizes vary due to the presence of toxic substances in the stream. Or, if these organisms simply vary in size due to their own individual growth rates.
In answering these two questions, the effect of common pollutants on salamanders must be identified. Because the majority of salamanders (at least the ones most common) at our field sites are lungless (family Plethodonitdae), their ability to absorb oxygen through their skin is pertinent to their survival (Pauley, 2010). As a result, the species needs clean, cool water for maintaining healthy populations. Without both of these criteria being met, they are unable to “breathe”. What are some factors that could keep them from being able to absorb this oxygen? Stream pollution is an obvious one. As Purdue University has discovered: with excess amounts of nitrogen or phosphorous in the stream, the amount of oxygen available depletes (“Water Quality”). This occurs because of the reaction between nitrate molecules and oxygen molecules; as well as phosphorous molecules and oxygen molecules. Both of these factors can accelerate plant growth and lead to oxygen deprivation in streams through photosynthesis.
As observed by Rex Springston of the Richland Times, a specific type of salamander called the Hellbender that relies solely on its ability to absorb oxygen through its skin, has been quickly disappearing throughout regions in the southeast. Springston (2013) interviewed various scientists throughout the state of Virginia who have observed this anomaly. The majority of those interviewed agreed that pollution as well as global warming caused by pollution has influenced the amount of Hellbenders seen in their state.
What does this have to do with the growth rate of salamanders you may ask? As discovered by Wood and Orr there is direct correlation between the size of the salamander and its oxygen intake (1967). The larger the amphibian, the more oxygen it will require. Therefore, it can be assumed that a larger salamander would be unable to survive in locations that more pollutants and less oxygen were present.
Throughout the course of this semester our class will be capturing and studying various salamander species that have felt the strong effects of pollution through ex-urbanization. It is obvious that the Hellbender alone is not a good enough reference to fully confirm or deny my hypothesis; this is where collecting a variety of species will become pertinent to this project. Because sampling sites will be in more mountainous regions, the types of salamanders observed will most likely include: black-bellied salamanders, shovel-nosed salamanders, and a variety of other mountain and stream-dwelling species. When collecting these species, I would like to identify and measure them to determine how each specific type has faired against the adversities of pollution and ex-urbanization. It is my hope that by the end of this creative inquiry, both my classmates and I will be more knowledgeable about exactly what effects ex-urbanization has on salamanders.
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Pauley, Thomas K. "Salamanders of West Virginia." www.wvdnr.gov. N.p., 04 Dec. 2010. Web. 1 Oct. 2013.
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Wood, Stephen C., and Lowell P. Orr. "Effects of Photoperiod and Size on the Oxygen Consumption of the Dusky Salamander, Desmognathus Fuscus." The Ohio Journal of Science 69 (1969): 122. The Ohio State University Knowledge Bank. Web. 1 Oct. 2013.