Cloudberries ripening in a stretch of tundra burned in the 2007 fire.
Scientist Gus Shaver amid the flowering cottongrass at the burn site. His colleague, Adrian Rocha, and the 3-meter tall tower that measures carbon exchange out on the tundra. It’s surrounded by an electric fence to keep out bears (more on that later).
The tundra from above.
Gus Shaver displays a cross-section of unburned tundra.
Toolik Lake, Day 3: The North Slope from above
Wednesday we took a helicopter ride out about 27 miles from Toolik Lake to what scientists here call “the burn site”—about 400 square miles of tundra that was scorched during a 2007 fire.
The Anaktuvuk River fire was the largest such fire on record. Some scientists think this unprecedented event shows that future fires on a tundra made warmer and drier by climate change could amplify the effects of global warming. The fire released carbon that had been locked in the peaty tundra soil, according to research and fieldwork conducted by University of Florida scientist Michelle Mack and her co-authors, including Gus Shaver of the Marine Biological Laboratory.
The fire also changed the ecosystem there. The dark, charred surface retains more heat than the previous mix of mosses and tussock grasses. Scientists think the loss of the insulating surface soil layer could destabilize the permafrost below, soemthing that could lead to further releases of carbon into the atmosphere. Their paper on the subject is being published Thursday in Nature (http://www.nature.com/nature/journal/v475/n7357/full/nature10283.html).
On Wednesday we inspected the main burn site, and compared growth of plants there and thaw depth of the permafrost with an unburned site nearby. MBL scientist Adrian Rocha has set up instrument towers at both sites that measure how much carbon the tundra there absorbs and releases into the atmosphere.
Once a stark contrast, by now the difference between the two locations is difficult to detect even by air. From above the recovering burn scar looks slightly browner than the unburned tundra, which is more of a drab olive color. But on the ground both sites looked alive with growth, dotted with flowering cottongrass and ripening cloudberries, a reddish-amber berry with a pleasingly tart taste.
“It’s wonderful out here,” Shaver said, as we walked back over the springy tussocks toward the waiting helicopter. “You really are alone.”
Later in the day we stopped over at Horn Lake, where thawing permafrost has resulted in a unique sort of erosion that scientists called “thermokarst.” As the ice in the permafrost melts and water drains away, the ground slumps, forming hollows and—in this case—tumbling down toward the water’s edge.
Just before heading back to the Toolik field station, we took a dramatic detour and flew over Atigun Gorge at the foot of the Brooks Mountain Range. Arctic sheep (known as Dall sheep) grazed on the steep, stony slopes above the Atigun River.
Toolik Lake, Day 3
We’re going up in a helicopter to check out burned sections of tundra from a sweeping 2007 fire. Pix and video to come!
