Interactions of Ipomoea aquatica and Utricularia reflexa with phytoplankton densities in a small water body in northern Nigeria

The interactions of Ipomoea aquatica and Utricularia reflexa with phytoplankton densities were studied in a small water body in Zaria, Nigeria from June to November 2007. The negative effects of both macrophytes on 10 out of 15 phytoplankton taxa, including Staurastrum sp., Netrium sp., Ulothrix sp., Marssionella sp. and Closterium sp. were differentiated from other environmental effects. U. reflexa, on the other hand, showed positive associations with species like Actinocyclus sp., Palmellopsis sp., Spirotaenia sp., Microcystis sp. and Marssionella sp. Qualitative phytochemical screening and FT-IR analyses confirmed the presence of glycosides, anthraquinone, saponins, steroids, triterpenes, flavonoids, and alkaloids in Ipomoea aquatica and Utricularia reflexa. The observed variations in phytoplankton community dynamics were closely related to the presence of these macrophytes as well as the environmental conditions in the pond.