Effects of freeze-thaw cycles on low temperature carbon mineralisation in peat
(English)Manuscript (preprint) (Other academic)
Recent investigations indicate that winter carbon emission from peatlands and low temperature carbon mineralisation processes conld have the potential to affect annual carbon budgets. Special emphasis has been put on periods of freeze-thaw events during spring and autumn. The aim of this study was to investigate the impact of freeze-thaw cycles on peat carbon mineralisation. This was addressed by following production rates and total amounts of CO,- and CH4-formation in surface (0-5 cm) and deep (45-50 cm) peat samples incubated at 4°C and comparing controls with replicate samples subjected to three consecutive freeze-thaw cyclesprior to incubation. Accumulation of fermentation products (H2, VF A and ethanol) were measured in order to gain further insight to the biogeochemical processes and transformation pathways involved. We conclude that freeze-thaw cycles affect both short and long term formation and exchange of C02 by altering the availability and amount of peat carbon substrates. Freeze-thaw events also resulted in an inhibition of methanogenesis with a concomitant accumulation in H2 and butyrate. We conclude that freezethaw cycling events can be of large importance for the carbon budgets of northern peatland ecosystems, although they are of a limited temporal duration.
Social Sciences Interdisciplinary
IdentifiersURN: urn:nbn:se:liu:diva-79155OAI: oai:DiVA.org:liu-79155DiVA: diva2:538487