Plasticity and Multiplicity of Trophic Modes in the Dinoflagellate Karlodinium and Their Pertinence to Population Maintenance and Bloom Dynamics

As the number of mixotrophic protists has been increasingly documented, “mixoplankton”, a third category separated from traditional categorization plankton into “phytoplankton” and “zooplankton”, become new paradigm research hotspot in aquatic ecology. While species dinoflagellates are dominant group among all recorded members mixoplankton, trophic modes Karlodinium, genus constituted cosmopolitan toxic species, were reviewed due to their representative features as mixoplankton harmful algal blooms (HABs)-causing dinoflagellates. Among at least 15 reported genus, three have intensively studied for modes, found be phagotrophic. Their phagotrophy exhibits multiple characteristics: (1) omnivority, i.e., they can ingest variety preys many forms; (2) flexibility phagotrophic mechanisms, small by direct engulfment much bigger myzocytosis using peduncle; (3) cannibalism, including K. veneficum dead cells own species. However, some recently described barely tropical still need investigated further regarding above-mentioned aspects. Mixotrophy Karlodinium plays significant role population dynamics formation HABs ways, which thus deserves investigation aspects physiological ecology, environmental triggers (e.g., levels inorganic nutrients and/or presence preys), energetics, molecular (genes gene expression regulations) biochemical relevant enzymes signal molecules) bases, origins, evaluation advantages being phagotroph.