Deep within the Arctic's permafrost, that top layer of soil there that never melts, live hundreds of thousands of microbes, many that produce methane. However, we still don't really know a lot about these mysterious microscopic creatures.
Recently, though, scientists at the Pacific Northwest National Laboratory (PNNL) gained new insight into how these microbes function, as well as discovered new species of these methane-producing microbes we didn't even know existed.
We also now know that those microbes aren't just living in a frozen stasis: many are actively producing methane, even in sub-zero temperatures.
"We know so little about them because the majority have never been cultivated and their properties are unknown," says microbiologist Janet Jansson. "This work hints at the life strategies they use when they've been frozen for thousands of years."
Beneath the frozen soil of permafrost lies another layer that cyclically thaws and refreezes, an "active layer." The permafrost traps a lot of carbon. However, if that permafrost melts, which is likely, thanks to global warming, that releases a lot of carbon for the microbes living in the slushy "bog" to feed upon, releasing methane as a byproduct.
"Estimates are that permafrost stores between 780 and 1,400 gigatons of terrestrial carbon. That's a huge reservoir," says Jansson. "What happens when permafrost thaws and trapped carbon is available for microbes?"
The PNNL study covered three types of soil from the Arctic: permafrost, active layer and bog soil. They used tools to identify and examine the genes of microbes, as well as study the proteins that allow these tiny creatures to survive in sub-zero temperatures.
Their results showed that microbes in the permafrost layer of soil had proteins that allowed them to survive extremely cold temperatures, as well as had the ability to move through the permafrost, feeding of off iron and methane to survive. Microbes in the active layer had other proteins that helped them seek out nutrients as their environment constantly freezes and thaws.
However, those microbes in the bog surprised scientists the most. Not only did they possess genetic material specifically designed for methane production, but the team also discovered several new species of these methane-producing microbes.
Of course, this still doesn't answer the question about what happens when the permafrost completely thaws out, although it looks like a lot of methane could be released, which could greatly increase global warming, perhaps pushing Earth past the tipping point. However, we now better understand the delicate ecosystems at work here deep within the Arctic soil.
