Researchers from the University of California, Berkeley and the U.S. Department of Energy’s Lawrence Berkeley National Laboratory have captured the first detailed microscopy images of ultra-small bacteria. These bacteria, which are believed to be as small as life can get, could have an impact on human health, Earth’s climate and our food and water supply but virtually nothing is known about them.

The cells identified by the researchers have an average volume of 0.009 cubic microns. According to the team, about 150 of them could fit inside a single E. coli cell, more than 150 thousand could fit onto the tip of a human hair.

The existence of such small organisms has been debated, but there has been no scientific description of them prior to the paper published in the February 27 edition of the journal Nature Communications.

Concentrating the cells into an analyzable sample was no small trick. Groundwater collected at Rifle, Colorado was run through a series of filters down to 0.2 microns. That is the last size used in the process of sterilizing water. The tiny microbes were then flash frozen at -272 degrees Celsius in a device called a cryo plunger to ensure that they weren’t damaged during transportation to the lab.

Researchers at Berkeley Lab using 2-D and 3-D “cryogenic transmission electron microscopy” which revealed that the bacteria were dividing, indicating that they were healthy.

Given that the cells are smaller than some researchers thought possible for life they are thought to be the smallest life forms that will ever be found. The cells contain densely packed spirals which are believed to be DNA, a very small number of ribosomes and a stripped down metabolism which researchers believe forces them to rely on other bacteria for survival.

“These newly described ultra-small bacteria are an example of a subset of the microbial life on earth that we know almost nothing about. 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,” says Jill Banfield, a Senior Faculty Scientist in Berkeley Lab’s Earth Sciences Division and a UC Berkeley professor in a statement.

According to the researchers, a better understanding of the bacteria could improve scientists understanding of everything from the planet’s climate to our food and water supply.

The bacteria’s genomes were sequenced at the Joint Genome Institute in Walnut Creek, California and were about 1 million base pares in length. Metagenomic and other DNA-based analyses of the samples were conducted at UC Berkeley where a diverse range of bacteria were found.

“There isn’t a consensus over how small a free-living organism can be, and what the space optimization strategies may be for a cell at the lower size limit for life. Our research is a significant step in characterizing the size, shape, and internal structure of ultra-small cells,” says Birgit Luef, a former postdoctoral researcher in Banfield’s group who has since moved to the Norwegian University of Science and Technology, Trondheim.

Among other things the team found that the bacteria have pili, thread-like appendages, which they believe could serve as connections to other microbes, which are required because the genomic data suggests that they lack many basic functions and must work as a community.