They're called "ultra-small bacteria," but "ultra-small" doesn't seem to do them justice. Instead, try "about as small as life can get," write researchers at the Lawrence Berkeley National Laboratory. They managed to capture the first-ever image of such an organism, no small feat given that the cells have an average volume of 0.009 cubic microns. Translation: You could fit 150,000 of them on the tip of a single human hair. This is "the smallest a cell can be and still accommodate enough material to sustain life," says the research team. Scientists have debated whether these things actually exist for about 20 years now, notes UPI. And while the argument may have been settled, researchers still don't quite grasp their role.
"These newly described ultra-small bacteria are an example of a subset of the microbial life on earth that we know almost nothing about," says Berkeley's Jill Banfield. "They probably play important roles in microbial communities and ecosystems, but we don't yet fully understand what these ultra-small bacteria do.” Scientists collected the microbes from filtered groundwater in Colorado, flash-froze the samples for transport to the lab, and took advantage of advances in electron microscopes to capture the image of the organism and sequence its genome. They're so "minimal" that they likely depend on other organisms to remain alive, reports Engadget. More research is needed to suss out that process and to answer what the Smithsonian says might be a bigger question: "Are there even smaller life forms out there?" (In less consequential "size matters" news, there's this.)