ABSTRACT

The protozoa and higher animals hydrolyze the solid organics internally rather than externally. Protozoa are identified entirely from their physical characteristics. Protozoologists consider flagellated algae as a major part of the phytoflagellated protozoa; but environmental microbiologists have kept the photosynthetic phytoflagellates with the algae and the non-photosynthetic phytoflagellates with the protozoa. Suctoria are interesting protozoa that look like stalked ciliated protozoa. Protozoa are primarily aerobic organisms, requiring dissolved oxygen as their electron acceptor. The metabolic data from the studies demonstrated that the aerobic growth of the protozoa followed the same general relationships of metabolism as the other microorganisms. In the natural environment the different groups of protozoa compete for nutrients. Like the other microscopic animals, the rotifers prefer bacteria as their source of food, but can eat small algae and protozoa. The crustaceans feed on bacteria, algae, protozoa, and solid organic materials.