Mixotrophy upgrades food quality for marine calanoid copepods

Inorganic nutrient limitation affects the stoichiometry and nutritional quality of marine phytoplankton. Mixoplankton, able to photosynthesize feed simultaneously in one cell, can compensate shortage nutrients by phagotrophy, theoretically upgrading their for predators: zooplankton. Yet, additional value that phagotrophy mixoplankton may provide support zooplankton growth recruitment has been poorly explored. Therefore, we investigated feeding reproductive performances copepods Paracartia grani Centropages typicus on mono-diets dinoflagellate Karlodinium veneficum grown as strict autotroph mixotroph, both under N P depletion, nutrient-balanced conditions (f/2 medium; only autotroph). Feeding reproduction outputs were generally higher P. than C. typicus. Both copepod species ingested mixotrophic K. at similar rates autotrophic ones either nutrient-limited scenario. However, egg production increased when mixotrophs, N- P-limited diets, limitation. In general, influenced physiology more depletion. Our results show upgrades mixotrophs prey compared ones. These findings are among first reported cases ingestion laboratory actively mixoplankton, they highlight importance considering trophic mode protist response various zooplanktonic predators attempting understand functioning planktonic food webs.