Algal Species Composition on Turtle Carapaces in Spring Lake, San Marcos, Texas

Abstract

Algae are found in a wide variety of habitats on the planet. They are found in the depths of the oceans, in freshwater lakes and streams, in different types of soil, in aerial habitats, and living in or on other organisms. One notable habitat is the carapaces of freshwater turtles. Historically, species of algae have been reported using turtles as their main substrate; however no study has statistically proven a difference in algal species composition among turtle species or if algae colonize specific substrates. This study, conducted in Spring Lake, San Marcos, Texas, determined significant differences in algae species, Basicladia chelonum (DF = 3, G2 = 195.53, P < 0.0001), Basicladia crassa (DF = 3, G2 = 24.38, P < 0.0001), and Cladophora glomerata (DF = 3, G2 = 250.59, P < 0.0001) among turtle species in Spring Lake. This study also determined that significant differences in algae species, C. glomerata (DF = 3, G2 = 32.43, P < 0.0001), Coleochaete scutata (DF = 3, G2 = 42.60, P < 0.0001), Rhizoclonium hieroglyphicum (DF = 3, G2 = 17.70, P < 0.001), and Lyngbya spp. (DF = 3, G2 = 20.84, P < 0.0001) among substrate types in Spring Lake. Factors that may influence the colonization of algae on freshwater turtles include turtle habit, light availability, and desiccation rates. The patterns in algal composition among turtle species and substrate types found in this study suggest a relationship between some algae species and freshwater turtles. The relationship can be considered to be commensalism; however the results from this study suggest mutualism.