Carbon cycling in an ombrotrophic bog and the effect of climate change. (5440)
Authors:
T. Moore* - McGill University J. Bubier - Mount Holyoke College P. Lafleur - Trent University
N. Roulet - McGill University
Abstract:
Northern peatlands, such as bogs, contain large stores of C (up to 200 kg C m-2), resulting from the long-term accumulation at rates of between 15 and 30 g C m-2 yr-1. At a large ombrotrophic bog, Mer Bleue, near Ottawa, we have been
investigating the controls on C accumulation using an eddy-covariance tower. Net Ecosystem Exchange (NEE) of CO2 shows strong seasonal patterns with the annual NEE ranging from –10 to –76 g C m-2, of which about 10 g C m-2 yr-1 is lost as CH4, DIC and DOC export. These differences are related to inter-annual variations in climate. Ecosystem Respiration (ER, or night-time NEE) is a primary control on the overall C balance, representing root respiration and organic matter
decomposition. ER varies seasonally and is strongly related to peat temperature, with Q10 values from 2.2 to 4.1, depending on location of temperature
measurement. Surprisingly, ER was only weakly related to water table position, primarily because of the generally low water table in this “dry” bog, though the influence of water table on ER is shown along wetter moisture gradients.
Speaker Information: Tim Moore, McGill University, Geographt Dept. 805 Sherbrooke St. W., Montreal, QC H3A 2K6; Phone: 514-398-4961; E-mail:
Session Information: Wednesday, November 3, 2004, 8:25 AM-11:45 AM Presentation Start: 9:00 AM
