I'm Elizabeth Webb, an ecosystemicologist interested in understanding climate change feedbacks in the Arctic and sub-Arctic. Along with other members of the ecosystem dynamics lab at the University of Florida, I set out to measure and study the carbon flux of the Alaskan tundra in the winter time. Most of the research on northern tundra has been done in the summertime when it's relatively easy to measure carbon flux by placing a chamber over the bare tundra. But things are much more complicated in the winter when there's a massive amount of snow on the ground and it's brutally cold and dark. In the Arctic, winter can last as much as seven months out of the year and air temperatures are expected to increase the most during the winter time as a result of climate change, so it's incredibly important to know what's going on during this period. We simulated future warming scenarios by constructing snow fences so that snow collects on the leeward side of the fence, insulating the soil from the cold air. So the plots on the snow build-up side of the fence are in effect warmer than those away from the fence. This allows us to study how warmer temperatures affect the amount of carbon that is released during the winter. We found that warming increased the amount of carbon dioxide released over the winter time by 9 to 36 percent depending on which method we used. When we added the amount of carbon lost during the winter to what we measured in the summer, we found that our field site was a carbon source, emitting more carbon than it takes in on an annual basis. This was true for both our experimentally warmed plots and our control plots, which indicates that our sub-arctic undersite could be shifting from its historical carbon sink to a carbon source.