Ocean bacteria using CO2 to grow: New Zealand scientist

Common ocean bacteria play a greater role in global climate processes than previously thought, says a New Zealand scientist who took part in research that found sunlight stimulates bacteria to use carbon dioxide (CO2) for growth when organic carbon food sources are scarce.

The international study found marine bacteria, which comprise up to 90 percent of the oceans' global biomass, had a significant role in the biogeochemistry of the oceans, University of Otago marine scientist Dr Federico Baltar said Tuesday.

The researchers studied a marine bacterium called Dokdonia, which contained a light-absorbing pigment named proteorhodopsin ( PR).

"We discovered that light profoundly affects Dokdonia's patterns of gene expression and metabolic activities, and that these responses are influenced by the availability of organic matter and its quality," Baltar said in a statement.

When they were exposed to light, the bacteria switched to obtaining a third of their cellular carbon from CO2.

"These bacteria's ability to use both inorganic and organic carbon to grow makes them remarkably flexible micro-organisms that can quickly adapt to the highly variable conditions in their ocean environment," he said.