Gephyrocapsa huxleyi is a prevalent, bloom-forming phytoplankton species in the oceans. It exhibits a complex haplodiplontic life cycle, featuring a diploid-calcified phase, a haploid phase and a third ‘decoupled’ phase produced during viral infection. Decoupled cells display a haploid-like phenotype, but are diploid. Here, we investigated the fate of decoupled cells during culture observations and we compared the transcriptome profiles and the cellular ultrastructure of the three life …