A research team led by Bigelow Laboratory for Ocean Sciences has discovered that marine microbes are adapted to very narrow and specialized niches in their environment. This may explain why so few of these microbes (usually less than one percent) can be grown for study in the laboratory. By using new genetic tools, the researchers’ ability to read and interpret genetic information from the remaining 99 percent will be pivotal in detecting and mitigating the impact of human activities in the ocean. Funded by the National Science Foundation, the study was published in the “Proceedings of the National Academy of Sciences of the United States of America” this week.

The cutting-edge technology that proved critical to the research, and was implemented on a large scale for the first time, is called single cell genomics.

“While other tools are available to analyze genes in uncultured microbes, they seldom tell us how these genes fit together and what microbes they come from,” said Ramunas Stepanauskas, the study’s senior author and director of the Bigelow Single Cell Genomics Center (SCGC). “By developing and applying high-throughput single cell genomics, we obtained the first near-complete genomic blueprints of many microbial types that dominate marine ecosystems but used to be inaccessible to scientific investigation.

“We found that natural bacterioplankton are devoid of ‘genomic pork,’ such as gene duplications and noncoding nucleotides, and utilize more diverse energy sources than previously thought,” Stepanauskas said. “This research approach opens a new chapter in the exploration of microbial life in the oceans and in other environments on our planet.”

Genomic streamlining is the rule, not the exception among marine bacterioplankton, according to Brandon Swan, lead author and postdoctoral researcher in the SCGC. “We also found that marine microbes are effectively dispersed around the globe, but they stay within their temperature ‘comfort zones.’

“Bacteria that thrive in the frigid Gulf of Maine don’t show up near Hawaii. However, as long as the temperature is right, the same types are found anywhere in the world, whether on the coast of British Columbia, Northern Europe, or Tasmania,” Swan said.

“Thanks to single cell genomics and other technological advances, we now have a much more accurate understanding of the biological diversity and processes taking place in the ocean,” said Tanja Woyke, a key co-author from the Department of Energy Joint Genome Institute. “The amount of adaptations and biochemical innovation that have accumulated in marine microorganisms over billions of years of evolution is astounding – a glass of seawater encodes more genetic information than a desktop computer can hold.

“This information represents a largely untapped source of novel natural products and bioenergy solutions, both essential for human well-being,” Woyke said.