New light is being cast by the research of a Texas A&M University oceanographer on the role “picky eater” microbes in the coastal zone play in the global carbon cycle.

A scientific paper based on the research by Thomas Bianchi has been published in Proceedings of the National Academy of Sciences. The study explores the microbial process occurring at the juncture between land and sea. Microbes break down much of the carbon found on earth, turning it into carbon dioxide, which is released either into the surrounding water or into the air.
But microbes can be "picky" eaters and tend to prefer algae that are easy to digest rather than more difficult items like large plant vegetation.

“Microbes, however, are ever-evolving life forms,” Bianchi explains.

“When they digest more difficult substances because it's mixed with easily digestible substances, scientists call it priming. The concept is not new, but the analytical tools we now have are, and this process has mostly been studied by soil scientists.

"Priming is like mixing M&Ms with non-digestible materials," Bianchi says. "Combine the easily digestible carbon with the more difficult carbon and the more difficult is consumed faster than previously thought."

Priming effects can be enhanced when increases in temperature produce more activity from microbes. In fact, organic carbon in rocks like shale, which is the largest reserve of organic carbon on the planet, can be consumed by microbes under the right conditions. The potential this reservoir has to contribute to increased carbon dioxide in the atmosphere is enormous.

"Priming has largely been ignored and needs to be considered in future carbon models and budgets," Bianchi says.

Bianchi is currently looking at the priming of material in coastal regions such as the Mississippi River Plume, where terrestrial and algal materials are commonly combined.

He developed his theory by reading a broad spectrum of research literature, particularly in soil agricultural, and applied it to how land and water might interact.

"This is the first report to the global community about how priming linkages between different systems may work at the interface between different ecosystems," Bianchi says. "The soil people are still way ahead of aquatic researchers on this one."

Bianchi's is the first peer-reviewed study to link how priming in the carbon cycle at the land-sea interface has the potential to dramatically influence carbon dioxide production. He claims that microbial microevolution is not incorporated enough into our understanding of carbon cycling, noting that his analysis adds a dimension to the global carbon cycle that has been overlooked.

"It is certainly a springboard to a more comprehensive understanding of the carbon cycle on a global level," he says. "Think of the world's massive delta systems like the Amazon and the Indus reserves of carbon stored within them. Extraordinary activity at the molecular level can have a tremendous impact of the amount of carbon in the atmosphere."