Canada — He is thinking about the past. How fires may have crackled across the tundra. He is squeezing the wetlands for evidence as if they were tea bags. He is measuring rings on trees that may be as old as 500 years.
Phil Camill is a climate-change scientist. For three nightless weeks in July 2009, under the Arctic sun, he and a small team of researchers traced the carbon footprint of the past through the soil, water and trees of northern Manitoba.
“We want to see how carbon and nutrient cycling in lake-water chemistry and wetland dynamics might change with climate warming,” said Camill, who is director of Bowdoin’s Environmental Studies Program. “These ecosystems are not all responding the same, so we are studying a lot of landscape variability.”
This was the last round of fieldwork in a three-year research odyssey funded by a grant from the National Science Foundation. In his search for carbon records, the entire tundra ecosystem is proving to be an archive.
With Camill is Bowdoin first-year student Allison Dupont ‘ 12, who piled into a car with her professor and his research cohorts to travel more than 2,500 miles to northern Manitoba. They reached their final destinationa rustic fishing lodgeby small plane.
“It’s one of those opportunities you can’t turn down,” she said. “It was so beautiful and amazing. The sun stays light all night and there we were in the middle of nowhere with a complete science lab set up. It’s crazy that I was having fun running water samples at one in the morning. .. How many students get the opportunity to go to the Arctic? It makes you want to just keep going north ….”
A significant part of the research has taken place in permafrost areas where Camill, a global change ecologist, samples cores of frozen wetland peat sediments. He is trying to determine when the wetlands formed, how much carbon has accumulated over the past 8,000 years, and the effect of fire on the wetlands.
“Wetlands and other northern soils tend to store large amounts of carbon in the soils,” noted Camill, “Possibly as much carbon as is in the atmosphere. So with a bit of atmospheric warming hastening decomposition, or with more fires happening, the wetlands could release more carbon dioxide.”
Camill and the other researchers also are examining the past dynamic of forest stands to try to reconstruct climate patterns through tree-ring analysis. In warmer years, tree rings appear to be wider.
Perhaps the most tantalizing early data from their fieldwork was retrieved from water samples and mud cores taken from more than 40 lakes in the region. Camill and Dupont traveled by float plane over hundreds of acres of tundra to get to their research sites.
“Some of the lakes up there look like giant pots of iced tea,” he said. “That’s because the wetlands leach out dissolved organic carbon. Presumably, as more of this organic material gets into them, it turns the lakes more acidic and constrains the plankton community. This could affect how much the plankton photosynthesize or bacteria decompose, thus turning the lakes into a greater source of carbon.”
This kind of research is providing yet more data for larger research questions about the responses of lakes, streams and oceans to increased carbon levels.
“How do ecosystems process this dissolved organic carbon?” Camill posited. “Are lakes and rivers passive conduits? How much are organisms, such as bacteria, actually processing and transforming this material?”
And what of the landscape itself?
“If for some reason the hydrology were to change and maybe things got wetter in these northern areas, as is expected,” he noted, “you might have bigger, more interconnected lakes that act as reservoirs where this material gets processed. That might turn these lakes into stronger sources of carbon … that could lead to more CO2 going into the atmosphere. But that’s an open question. Nobody really knows.”