First detailed microscopic images of 'ultra-small bacteria' are representing the lowest possible size for life on earth. For long, researchers have debated about the existence of small bacteria, but there has never been such a detailed observation of the microbes.

Scientists from Lawrence Berkeley National Laboratory and the University of California, Berkeley, have taken the images. As per Dr. Jill Banfield from Berkeley Lab's Earth Sciences Division said that ultra-small bacteria is a subset of the microbial life on earth of which they do not know much.

"They're enigmatic. These bacteria are detected in many environments and they probably play important roles in microbial communities and ecosystems. But we don't yet fully understand what these ultra-small bacteria do", affirmed Dr. Banfield.

The team filtered groundwater collected in Rifle to 0.2 microns. The researchers said that when water is filtered to such a level then it is generally considered sterile, but when they assessed the water sample then it was teeming with the tiny microbes.

These microbes were so tiny that about 22,500,000 of the bacteria could fit onto the top of a human hair. The researchers froze the water sample and took it to Berkeley Lab. The researchers assessed the bacteria and at the Joint Genome Institute in Walnut Creek, Calif, the bacteria genomes were sequenced.

The researchers noticed many hair-like appendages that were radiating from the ultra-small bacterial cell. Dr. Birgit Luef was of the view that there is no consensus over how small a free-living organism can be.

The research is quite an important step in characterizing the shape, size and internal structure of ultra-small cells. The team said that earlier there was only a hypothesis over the presence of such bacteria, but they have been able to prove the existence of the same and are quite thrilled with their new accomplishment.