Tracking the fate of ancient carbon in the Siberian Arctic

The Siberian Arctic is one of the most remote and pristine corners of the planet. During the brief summer season, temperatures can climb into the 90s Fahrenheit, and the seemingly endless expanse of boreal forest — or taiga — and tundra explodes with plant and animal life. Every summer since 2008, R. Max Holmes and colleagues from the Woods Hole Research Center have brought a growing international team of undergraduate and graduate students halfway around the world to the Northeast Science Station near Cherskiy, Siberia. The project, called Polaris, is designed to immerse students in the arctic environment and mentor them as they carry out their own original research on permafrost, the supposedly permanently frozen soil beneath their feet.

During the Pleistocene, about 2 million to 11,000 years ago, herds of mega-herbivores including mammoth and woolly rhinoceros grazed vast, fertile grasslands that stretched across the entire Arctic. Over thousands of years, the carbon-rich remains of this productive ecosystem were slowly compacted and frozen into the soil. The amount of carbon stored in Arctic permafrost soil is estimated to be 1,500 billion tons — more than double what is currently in our atmosphere or four times as much as all of the forests on Earth.

However, as temperatures in this region steadily rise, the permafrost is thawing, and the resulting gooey, carbon-rich soil is becoming a fresh source of food for modern microbes. As the microbes consume this ancient food, they respire methane and carbon dioxide, both potent greenhouse gases.

The fieldwork in Cherskiy is not glamorous. Team members battle hordes of mosquitoes and navigate treacherous bogs to collect their samples and make their measurements. A permafrost team drills through the concretelike soil to extract 50-foot-long cores, while an aquatic team measures the carbon in the lakes, rivers and streams. They are driven by questions that affect the entire planet. How fast is the permafrost thawing? How much carbon is being converted to methane and carbon dioxide? And when will the changes in the Siberian Arctic impact decision-makers in Washington, D.C.?

Chris Linder is a documentary photographer, filmmaker and multimedia producer specializing in stories about science. He is a Senior Fellow in the International League of Conservation Photographers. To see more of his work, visit www.chrislinder.com.