Light-mediated interactions in pennate diatoms (Can you see the light?)*

Communication between conspecific individuals is an essential part of life both in terrestrial and marine realms. Until recently, social behavior in marine phytoplankton was assumed to rely mainly on the secretion of a variety of infochemicals that allow population-scale collective responses. However, recent findings reveal that pennate diatoms also utilize light-driven intercellular communication, likely mediated by autofluorescence emission in the red spectral band and photoreceptor proteins of the phytochromes superfamily, that facilitate collective behavior and synchronous sinking. Our work offers novel insights into a little-known aspect of the marine microbial world: communication through light.