Response of a tundra ecosystem to elevated atmospheric carbon dioxide and CO{sub 2}-induced climate change. [Annual report]

• Main Author: Oechel, W.C.
• Language: unknown
• Published: 2014
• Subjects: 54 ENVIRONMENTAL SCIENCES; TUNDRA; ARCTIC REGIONS; TERRESTRIAL ECOSYSTEMS; CARBON DIOXIDE; ECOLOGICAL CONCENTRATION; PROGRESS REPORT; CLIMATE MODELS; SEASONAL VARIATIONS; CARBON CYCLE; PERMAFROST; METHANE; Arctic; Climate change; permafrost; Tundra
• Online Access: http://www.osti.gov/servlets/purl/230286; https://www.osti.gov/biblio/230286; https://doi.org/10.2172/230286

Predicting the response of northern ecosystems to increases in atmospheric CO{sub 2} and associated climatic change is important for several reasons, including the fact that northern ecosystems contain large stores of carbon, most of which is below ground and because northern ecosystems could conceivably be either sources or sinks for CO{sub 2} under future climatic and atmospheric CO{sub 2} concentrations. The carbon in northern ecosystems is equal to about 20% of the world`s terrestrial carbon and about 70% of the carbon currently in the atmosphere. Eighty-three percent of this carbon is below ground in the seasonally-thawed upper soil layers and in the permanently frozen zone, the permafrost. Because of bogs and permafrost, northern ecosystems are unusual in that they can potentially store significant amounts of carbon over long time periods. Most other mature ecosystems have little capacity for long- term carbon storage. Given the right conditions, northern ecosystems can also release a significant amount of carbon. A substantial amount of the carbon stored in northern ecosystems, and much of the future storage potential, is in the tundra regions. These systems could conceivably act as sources or sinks depending on developing climatic and atmospheric conditions. Our recent work indicates that elevated CO{sub 2} alone will have little effect on carbon storage in the tundra. However, the combination of elevated atmospheric CO{sub 2} (+ 340 ppm) and air temperature (+4{degrees}C) in the absence of any change in soil water table or soil moisture content, should result in significant increases in carbon sequestering in the tundra. However, if changing climate results in a decrease in the water table and soil moisture levels, this may lead to sizeable losses of carbon from the tundra soils.