T232 Carbon and Water Dynamics in Peatlands and Their Relationship to Climatic Change

Wednesday, 12 October 2011
8:00 AM - 12:00 PM
Room M101AB

THE RED LAKE PEATLAND OBSERVATORY (RLPO): A MULTI-SENSOR INSTRUMENT ARRAY FOR MONITORING CARBON-WATER DYNAMICS IN A LARGE NORTHERN PEATLAND

Paper number: T232-9
Program: Technical Sessions
Time: 10:15 AM – 10:30 AM

Authors

Abstract

The 1200 sq km Red Lake peatland in northern Minnesota has been the focus of an ongoing study of carbon-groundwater interactions for over 30 years. Building upon past work we installed 20 new instrument stations in the central RLII bog-complex to monitor fluxes of carbon, water, and heat continuously within the 4m-thick peat profile and also the atmospheric boundary-layer on scales of meters to kilometers. This integrated array of stations comprise the Red Lake Peatland Observatory (RLPO), which now collects data from a) 14 dual-frequency GPS units measuring vertical and lateral deformations of the peat mass caused by changes in water and gas storage, b) 2 eddy covariance units that monitor fluxes in heat, momentum, carbon dioxide, and water vapor across the atmospheric boundary layer, and c) 4 stations equipped with instrumented piezometers and meteorological sensors for measuring changes in water and gas storage within the entire peat profile. All remote stations communicate by radio to a base station and through the internet to a centralized database at the University of Minnesota that automatically downloads and stores sensor data on a daily basis.

Each fall zones of overpressure formed within the shallow (50-150 cm) peat of the bog, poor-fen, and lawn sites apparently in response to the buildup of biogenic gases related to a) the cessation of the growing season and b) a decline in methane emissions through vascular plants. Transient zones of overpressure also developed within the deeper peat but the head gradients indicate that an overall trend of downward flow prevailed at all sites since the onset of wetter conditions in August of 2009. This flow regime would support the downward transport of labile root exudates into the deeper peat providing a stimulus for methanogenesis. Overall data from the RLPO indicates a dynamic interaction among climate, hydraulics, and carbon cycling with an especially close coupling between biogenic gases and groundwater flow.

Additional Co-authors: Elizabeth J. Corbett; Malak M. Tfaily; Andrew Parsekian