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.
