Transfer of carbon dioxide and methane through the soil-water-atmosphere system at Mer Bleue peatland, Canada

✍ Scribed by Kerry J. Dinsmore; Mike F. Billett; Tim R. Moore

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 234 KB
• Volume: 23
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/hyp.7158

✦ Synopsis

Surface waters associated with peatlands, supersaturated with CO 2 and CH 4 with respect to the atmosphere, act as important pathways linking a large and potentially unstable global repository of C to the atmosphere. Understanding the drivers and mechanisms which control C release from peatland systems to the atmosphere will contribute to better management and modelling of terrestrial C pools. We used non-dispersive infra-red (NDIR) CO 2 sensors to continuously measure gas concentrations in a beaver pond at Mer Bleue peatland (Canada); measurements were made between July and August 2007. Concentrations of CO 2 in the surface water (10 cm) reached 13 mg C l 1 (epCO 2 72), and 26 mg C l 1 (epCO 2 133) at depth (60 cm). The study also showed large diurnal fluctuations in dissolved CO 2 which ranged in amplitude from ¾1Ð6 mg C l 1 at 10 cm to ¾0Ð2 mg C l 1 at 60 cm depth. CH 4 concentration and supersaturation (epCH 4 ) measured using headspace analysis averaged 1Ð47 mg C l 1 and 3252, respectively; diurnal cycling was also evident in CH 4 concentrations. Mean estimated evasion rates of CO 2 and CH 4 over the summer period were 44Ð92 š 7Ð86 and 0Ð44 š 0Ð25 µg C m 2 s 1 , respectively. Open water at Mer Bleue is a significant summer hotspot for greenhouse gas emissions within the catchment. Our results suggest that CO 2 concentrations during the summer in beaver ponds at Mer Bleue are strongly influenced by biological processes within the water column involving aquatic plants and algae (in situ photosynthesis and respiration). In terms of carbon cycling, soil-stream connectivity at this time of year is therefore relatively weak.