An international research team led by scientists from the University of Vienna found several bacteria that use DNA as a food source in samples of Atlantic ocean sediment. The study was published in “Nature Microbiology” and provides new insights into the biodiversity and function of the microscopic life of the ocean, which is largely still unexplored.
Microbes are able to use various molecules as nutrients, including proteins and fats of dead and rotting organisms. “DNA is basically a fertilizer. It consists of a chain of millions of sugar molecules and phosphorus and nitrogen bases,” explains microbiologist Kenneth Wasmund, the study’s author.
When an organism dies, extracellular DNA molecules are released, which are then found in the environment. Microbes that break down these and other biological molecules play a significant role in global biogeochemical processes because they recycle organic material from the ocean and affect how much carbon dioxide reaches the bottom.
The oceans cover more than 70 percent of the Earth’s surface, and the sediments of the ocean floor provide habitat for thousands of microbial species. Most of these organisms are still unknown.
“Our study identified some of these microbes and discovered their way of life. We investigated whether and how microbes living on the ocean floor use DNA as a food source,” Wasmund said.
For the purposes of the study, samples were collected from Baffin Bay, which is located in the edge sea of the Atlantic Ocean between Greenland and Canada. In order to identify DNA-feeding microbes in the samples, the research team used experimental, analytical and bioinformatics methods.
In the laboratory, the scientists fed the bacteria with purified DNA marked with heavy carbon atoms and discovered which bacteria decompose DNA.
They have enzymes that break down DNA into smaller pieces so they can eat it. One of the newly discovered bacteria has a specially developed mechanism like this. Scientists called it “Izemoplasma acidinucleici”.