Posted by Alumni from MIT
October 20, 2026
The oxygen in about every other breath we take comes from microscopic cells ' phytoplankton ' drifting in the surface of the ocean. Among them is Prochlorococcus, the smallest and most abundant photosynthetic organism in the seas. It single-handedly accounts for roughly 10 percent of all the carbon that the land and the oceans pull from the atmosphere each year. Since its discovery decades ago by MIT Institute Professor Sallie (Penny) Chisholm and colleagues, Prochlorococcus has been known as the loner microbe, free-floating along and drifting through sunlit ocean waters. Because it lives and dies quickly near the water's surface, Prochlorococcus was thought to contribute very little to the ocean's biological pump, the natural process of moving carbon into the deep ocean and storing it there. In an open-access study published in Nature Communications, they demonstrate Prochlorococcus can also form biofilms, sticky communities of cells attached to surfaces. The finding suggests that... learn more