This is a summary of a story that originally appeared on Nicholas School of the Environment. 

The Southern Ocean surrounding Antarctica plays an outsize role in global climate, largely thanks to tiny, drifting organisms called plankton that soak up carbon. Researchers recently completed the most comprehensive survey to date of DNA associated with these microbes. The survey paves the way for a better understanding of their role in climate change. 

“We wanted to better understand microbial diversity in the , because those microbes affect the carbon cycle in different ways,” said Nicolas Cassar, Lee Hill Snowdon Bass Chair at the Nicholas School of the Environment, who collaborated with an international team on the research. 

For example, certain microscopic marine organisms called phytoplankton are responsible for half the photosynthesis on Earth, meaning they take up a substantial amount of carbon dioxide from the atmosphere.

The researchers analyzed DNA from water samples collected throughout the Southern Ocean during a three-month expedition in late 2016 and early 2017. After sequencing the DNA, they cross-referenced their results with data on known genes, called gene catalogs. Next, they divided their samples into groups based on genetic similarities, such as adaptation to cold temperatures.

Remarkably, at least a third of the genes identified are missing from existing marine gene catalogs, underscoring how little we know about microbial life on our planet, according to Cassar.

“When we looked at the databases, a huge portion of these genes just wasn’t there. That’s a sign we’re charting largely uncharacterized genetic territory,” he said.

The next step is to dig deeper into this newfound genetic diversity to ultimately understand how it affects, and is affected by, climate change, according to Cassar.  

“Microbes regulate much of the ocean’s chemistry,” he said. “To understand how the Southern Ocean will influence future climate, we need to understand the genes that control those microbial processes.”

For more information go to Nicholas School of the Environment. 


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