The carbon cycle is the means by which carbon is moved between the world's soils, oceans, atmosphere, and living organisms. Northern tundra ecosystems play a key role in the carbon cycle because the cold, moist, and frozen soils trap organic material and slow their decomposition. This very slowly decaying organic material has caused carbon to build up in the Arctic during the past thousands of years. Historically, the tundra has stored large amounts of carbon. Now warming in the Arctic is slowly causing the permafrost to thaw and the tundra to become warmer and dryer. As the earth warms and permafrost thaws, this previously frozen carbon is released as carbon dioxide and goes into the atmosphere, turning the tundra into a source of carbon, rather than a sink. Because carbon dioxide is a greenhouse gas, this additional carbon dioxide creates a positive feedback that leads to even further warming.
Little is known about respiration in the arctic winter. The team used five different methods to find the best way to measure how much carbon is being released from northern ecosystems in the winter. Measuring winter respiration directly from experimentally warmed plots and understanding the drivers of wintertime tundra respiration have the added benefit of being able to improve global arctic carbon models. More information about the project can be found here.