Abstract
Dinoflagellates are unicellular eukaryotes with striking cell-biology and genomes and are major drivers of global primary production. Marine Prorocentrum cordatum has a barrel-like chloroplast, reticular mitochondrion, and unique nucleus. A photosystem megacomplex also comprising diverse pigment-binding proteins fosters adaptability to changing light regimes. Climate-forced heat stress evokes reduced cell yields correlating with modulated photosynthesis, central metabolism, and biosynthesis.