Species of Desmodesmus and Scenedesmus are well known to occur
in many aquatic environments and can even withstand harsh conditions.
They exhibit a high degree of phenotypic plasticity in response
to prevailing conditions. For example, some species form multicellular
colonies (coenobia) in the presence of chemical cues of excretions from
zooplankton grazers, and later disintegrating into unicellular forms in
deeper waters [11]. A species of Scenedesmus that maintained its
coenobial morphology was found within subcutaneous granuloma
in cichlids [12]. However, as far as we know, the species has never
been found in such parasitic form and the observed clumping of species
of Scenedesmaceae into green spots has never been reported in
the literature.