 Fluorescent microscopy verifies the presence of the phytoplankton, while the accumulation of phytoplankton in starved D. hemprichi and subsequent increasing levels of phaeopigments determine that phytoplankton is being consumed and digested.Furthermore, the depletion of phytoplankton concentrations in water currents downstream of D. hemprichi colonies also support the energetic pathway designating phytoplankton as the main source of energy for D. hemprichi.D.