Impact of light and nutrient availability on the phagotrophic activity of harmful bloom-forming dinoflagellates.
Catalina Mena, Marc Long, Ophélie Lorand, Pascale Malestroit, Emilie Rabiller, Jean-François Maguer, Stéphane L'helguen, Aurore Regaudie De Gioux
Author Information
Catalina Mena: Écologie Pélagique (DYNECO/PELAGOS), Institut Français de Recherche pour l'Exploitation de la Mer, IFREMER, 29280 Plouzané, France. ORCID
Marc Long: Écologie Pélagique (DYNECO/PELAGOS), Institut Français de Recherche pour l'Exploitation de la Mer, IFREMER, 29280 Plouzané, France.
Ophélie Lorand: Écologie Pélagique (DYNECO/PELAGOS), Institut Français de Recherche pour l'Exploitation de la Mer, IFREMER, 29280 Plouzané, France.
Pascale Malestroit: Écologie Pélagique (DYNECO/PELAGOS), Institut Français de Recherche pour l'Exploitation de la Mer, IFREMER, 29280 Plouzané, France.
Emilie Rabiller: Écologie Pélagique (DYNECO/PELAGOS), Institut Français de Recherche pour l'Exploitation de la Mer, IFREMER, 29280 Plouzané, France.
Jean-François Maguer: University of Brest, CNRS, IRD, IFREMER, Laboratoire des sciences de l'environnement marin (LEMAR), F-29280 Plouzané, France.
Stéphane L'helguen: University of Brest, CNRS, IRD, IFREMER, Laboratoire des sciences de l'environnement marin (LEMAR), F-29280 Plouzané, France.
Aurore Regaudie De Gioux: Écologie Pélagique (DYNECO/PELAGOS), Institut Français de Recherche pour l'Exploitation de la Mer, IFREMER, 29280 Plouzané, France.
Phagotrophy is a key nutritional mode for many bloom-forming dinoflagellates that can supplement their carbon and nutrient requirements. However, the environmental drivers and ecological relevance of phagotrophy in algal blooms are still poorly understood. This study evaluates the effect of light and nutrient availability on the phagotrophic activity of three common bloom-forming dinoflagellates (, and ) using three fluorescently labeled preys: bacteria, and the haptophyte . The three dinoflagellates exhibited distinct responses to light and nutrient availability in terms of growth, cell size, prey ingestion and preference. and showed higher cell-specific ingestion rates on bacteria (0.53 ± 0.13 and 1.64 ± 0.39 prey dinoflagellate h, respectively) under co-limited nutrient and light availability, whereas showed higher ingestion on (0.93 ± 0.22 prey dinoflagellate h) under low-light availability alone. However, the three dinoflagellates exhibited the highest carbon and nitrogen-specific ingestion rates when feeding on the larger prey . Our findings indicate that phagotrophy could be of advantage in short periods of light or nutrient limitation and may play different roles during the development of blooms, likely influencing the energy transfer through the food web.
