The abundance and distribution of Filinia Terminalis in various types of lakes as related to temperature,oxygen, and food

Although morphologically variable, Filinia terminalis constitutes a well defined ecological unit living below 12–15°C, and forming large maxima up to several thousand ind./l at an oxygen content < 2 mg/l. Field investigations and laboratory experiments indicate facultative anaerobiosis and food sources of chemosynthesizing or plankton decomposing bacteria. On the grounds of these physiological requirements a hypothetical schema is presented attempting to predict the occurrence of the two species, F. terminalis and F. longiseta in oligotrophic, eutrophic, meromictic, and polymictic, shallow lakes.