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Spatiotemporal variations of p CO 2 and δ 13 C‐DIC in subarctic streams in northern Sweden
Author(s) -
Giesler Reiner,
Mörth CarlMagnus,
Karlsson Jan,
Lundin Erik J.,
Lyon Steve W.,
Humborg Christoph
Publication year - 2013
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1002/gbc.20024
Subject(s) - streams , subarctic climate , tundra , bedrock , dissolved organic carbon , hydrology (agriculture) , environmental science , taiga , geology , environmental chemistry , chemistry , oceanography , ecology , geomorphology , arctic , computer network , geotechnical engineering , computer science , biology
Current predictions of climate‐related changes in high‐latitude environments suggest major effects on the C export in streams and rivers. To what extent this will also affect the stream water CO 2 concentrations is poorly understood. In this study we examined the spatiotemporal variation in partial pressure of CO 2 ( p CO 2 ) and in stable isotopic composition of dissolved inorganic carbon (δ 13 C‐DIC) in subarctic streams in northern Sweden. The selected watersheds are characterized by large variations in high‐latitude boreal forest and tundra and differences in bedrock. We found that all streams generally were supersaturated in p CO 2 with an average concentration of 850 µatm. The variability in p CO 2 across streams was poorly related to vegetation cover, and carbonaceous bedrock influence was manifested in high DIC concentrations but not reflected in either stream p CO 2 or δ 13 C‐DIC. Stream water p CO 2 values were highest during winter base flow when we also observed the lowest δ 13 C‐DIC values, and this pattern is interpreted as a high contribution from CO 2 from soil respiration. Summer base flow δ 13 C‐DIC values probably are more affected by in situ stream processes such as aquatic production/respiration and degassing. A challenge for further studies will be to disentangle the origin of stream water CO 2 and quantify their relative importance.