Winter climate controls soil carbon dynamics during summer in boreal forests

• Published in: Environmental Research Letters
• Main Authors: Mahsa Haei, Mats G Öquist, Juergen Kreyling, Ulrik Ilstedt, Hjalmar Laudon
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Publishing 2013
• Subjects: summer season; carbon dynamics; boreal forest; heterotrophic CO2 production; dissolved organic carbon; soil frost; Environmental technology. Sanitary engineering; TD1-1066; Environmental sciences; GE1-350; Science; Q; Physics; QC1-999; Northern Sweden
• Online Access: https://doi.org/10.1088/1748-9326/8/2/024017; https://doaj.org/article/6b679d6d4c6c46878e13f70a19aea858

Boreal forests, characterized by distinct winter seasons, store a large proportion of the global terrestrial carbon (C) pool. We studied summer soil C-dynamics in a boreal forest in northern Sweden using a seven-year experimental manipulation of soil frost. We found that winter soil climate conditions play a major role in controlling the dissolution/mineralization of soil organic-C in the following summer season. Intensified soil frost led to significantly higher concentrations of dissolved organic carbon (DOC). Intensified soil frost also led to higher rates of basal heterotrophic CO _2 production in surface soil samples. However, frost-induced decline in the in situ soil CO _2 concentrations in summer suggests a substantial decline in root and/or plant associated rhizosphere CO _2 production, which overrides the effects of increased heterotrophic CO _2 production. Thus, colder winter soils, as a result of reduced snow cover, can substantially alter C-dynamics in boreal forests by reducing summer soil CO _2 efflux, and increasing DOC losses.