Ecological factors affecting the distribution of Volvox species in small ponds

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White, Arthur J.
Senft, W. Herbert
Issue Date
Thesis (M.A.)--Ball State University, 1981.
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Factors influencing the distribution of Volvox spp. in 41 ponds of the Lake Itasca region, Minnesota, were investigated from May 25 through July 14, 1980. Twenty-two ponds had Volvox populations. The three species of Volvox found were: V. aureus Ehr., V. globator L. and V. tertius Meyer. Usually only one species was present in a pond with rare co-occurrence of two species. Only two of the 41 ponds contained two Volvox species simultaneously for a short time.Group comparison tests of ponds with and without Volvox showed three parameters to be significant (P > 0.05 level). Mean total phosphorus was higher in ponds with Volvox (x = 1.75 uM/1) than without (x = 0.95 uM/1). Mean temperature (20.4°C versus 21.8°C) and mean pH calculated from H+ concentrations (6.32 versus 6.76) were both lower in ponds with Volvox than in ponds without. Field observations of one pond revealed a patchy distribution of V. globator related to macrophyte abundance. Laboratory investigations confirmed that V. globator colonies orient to the aquatic moss Drepanocladus revolvens.Ball State UniversityMuncie, IN 47306