Evasion of CO2 from streams: The dominant component of the carbon export through the aquatic conduit in a boreal landscape
2013 (English)In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 19, no 3, 785-797 p.Article in journal (Refereed) Published
Evasion of gaseous carbon (C) from streams is often poorly quantified in landscape C budgets. Even though the potential importance of the capillary network of streams as C conduits across the land-water-atmosphere interfaces is sometimes mentioned, low-order streams are often left out of budget estimates due to being poorly characterized in terms of gas exchange and even areal surface coverage. We show that evasion of C is greater than all the total dissolved C (both organic and inorganic) exported downstream in the waters of a boreal landscape. In this study evasion of carbon dioxide (CO2) from running waters within a 67 km2 boreal catchment was studied. During a four year period (2006-2009) 13 streams were sampled on 104 different occasions for dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC). From a locally determined model of gas exchange properties, we estimated the daily CO2 evasion with a high-resolution (5×5 m) grid based stream evasion model comprising the entire ~100 km stream network. Despite the low areal coverage of stream surface the evasion of CO2 from the stream network constituted 53% (5.0 (±1.8) g C m−2 yr−1) of the entire stream C flux (9.6 (±2.4) g C m−2 yr−1) (lateral as DIC, DOC and vertical as CO2). In addition, 72% of the total CO2 loss took place already in the 1st and 2nd order streams. This study demonstrates the importance of including CO2 evasion from low-order boreal streams into landscape C budgets since it more than doubled the magnitude of the aquatic conduit for C from this landscape. Neglecting this term will consequently result in an overestimation of the terrestrial C sink strength in the boreal landscape.
Place, publisher, year, edition, pages
2013. Vol. 19, no 3, 785-797 p.
IdentifiersURN: urn:nbn:se:uu:diva-184696DOI: 10.1111/gcb.12083ISI: 000314219700011OAI: oai:DiVA.org:uu-184696DiVA: diva2:567403