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Research article - Peer-reviewed, 2013

Evasion of CO2 from streams - The dominant component of the carbon export through the aquatic conduit in a boreal landscape

Wallin, Marcus; Grabs, Thomas; Buffam, Ishi; Laudon, Hjalmar; Ågren, Anneli; Öquist, Mats; Bishop, Kevin

Abstract

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 landwateratmosphere 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 67km2 boreal catchment was studied. During a 4year period (20062009) 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 (5x5m) grid-based stream evasion model comprising the entire 100km stream network. Despite the low areal coverage of stream surface, the evasion of CO2 from the stream network constituted 53% (5.0 (+/- 1.8) gCm-2yr-1) of the entire stream C flux (9.6 (+/- 2.4) gCm-2yr-1) (lateral as DIC, DOC, and vertical as CO2). In addition, 72% of the total CO2 loss took place already in the first- and second-order streams. This study demonstrates the importance of including CO2 evasion from low-order boreal streams into landscape C budgets as 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.

Keywords

carbon budget; Greenhouse gases; headwaters; inland waters; water-atmosphere exchange

Published in

Global Change Biology
2013, volume: 19, number: 23, pages: 785-797

Authors' information

Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
Uppsala University
Grabs, Thomas
Buffam, Ishi
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment

Associated SLU-program

SLU Future Forests

UKÄ Subject classification

Forest Science

Publication Identifiers

DOI: https://doi.org/10.1111/gcb.12083

URI (permanent link to this page)

https://res.slu.se/id/publ/50359