Colour range of euglenoid (Euglenophyceae) blooms

Abstract

The presence of autotrophs, heterotrophs and mixotrophs among euglenoid taxa, multiple means of nutrition, and high tolerance to a wide range of thermal living conditions contribute to their colonization of various types of water bodies in different climatic zones. The formation of water “blooms” by euglenoids occurs during accelerated development and intensive cell division of these organisms. Euglenoids outcompete other microalgae and produce significant biomass under favorable conditions. The ability to produce temporal, reproductive and protective cysts also contributes to rapid bloom formations. Our observations suggest that their features probably make them model organisms for observing environmental changes in small water bodies. So far, little attention has been given to the species-dependent color variation of euglenoid blooms. Long-time research on euglenoid taxonomy, biogeography and habitat observations allow observers to recognize different blooms depending on the species causing the phenomenon: Euglena sanguinea, E. mutabilis, E. clara, E. hemichromata, E. geniculata, E. agilis, Euglenaria anabaena, Euglenaformis chlorophoenica, Monomorphina pyrum, Phacus pleuronectes, Ph. orbicularis, Lepocinclis ovum, Trachelomonas volvocina, T. volvocinopsis and T. caudata. The color range of euglenoid blooms are presented here for the first time.