Microscopic marine life includes genetically diverse lifeforms. This image shows diatoms, a type of microalgae, collected in Russian waters and arranged on a microscope slide in 1952 by Albert Brigger. The scale bar is one-tenth of a millimeter.California Academy of Sciences/Flickr
Microscopic marine life forms help in generating oxygen and taking up carbon dioxide just like rainforests on land. But how do they know when it is day or night? Can they see? By analysing RNA from seawater samples, researchers have now identified four main groups of photoreceptors (cells that are triggered by light). The team notes that the discovery could help in the field of optogenetics, where light is used to control a cell's functions.