Sensitivity of stream dissolved organic carbon to temperature and discharge: Implications of future climates
2016 (English)In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 121, no 1, 126-144 p.Article in journal (Refereed) PublishedText
Dissolved organic carbon (DOC) is a significant constituent in aquatic ecosystems with concentrations in streams influenced by both temperature and water flow pathway dynamics associated with changes in discharge (streamflow). We investigated the sensitivity of DOC concentrations in 12 high-latitude headwater streams to changes in temperature and discharge using a mathematical model. The implications of differences in sensitivities were explored by using downscaled projections of air temperature and discharge to simulate possible trajectories of DOC concentrations in a changing climate. We found two distinct responses: (i) catchments where stream DOC sensitivity was high to temperature but low to discharge and (ii) catchments where stream DOC sensitivity was low to temperature but high to discharge. Streams with strong seasonal DOC dynamics were more sensitive to temperature changes than nonseasonal systems. In addition, stream DOC sensitivity to discharge was strongly correlated with vertical soil water DOC differences in the near-stream zone. Simulations of possible future changes in DOC concentrations indicated median increases of about 4-24% compared to current levels when using projections of air temperature and discharge but even larger increases were observed for base flow concentrations (13-42%). Streams with high-temperature sensitivity showed the largest increases in DOC concentrations. Our results suggest that future climatic changes could bring significant increases in surface water DOC concentrations in boreal and hemiboreal areas but that the response ultimately is dependent on vertical soil solution DOC differences and soil organic carbon distribution.
Place, publisher, year, edition, pages
2016. Vol. 121, no 1, 126-144 p.
DOC, modeling, boreal, hemiboreal, uncertainty analysis, RIM
IdentifiersURN: urn:nbn:se:uu:diva-280922DOI: 10.1002/2015JG002922ISI: 000370173100008OAI: oai:DiVA.org:uu-280922DiVA: diva2:912268
FunderSwedish Research Council Formas, 2006-1235Swedish Environmental Protection AgencySwedish Research Council FormasThe Kempe FoundationsMistra - The Swedish Foundation for Strategic Environmental Research