Is in-stream processing an important control on spatial changes in carbon fluxes in headwater catchments

Julian James Charles Dawson, C. Bakewell, M. F. Billett

    Research output: Contribution to journalArticle

    86 Citations (Scopus)

    Abstract

    Data on small-scale spatial variations in instantaneous fluxes and concentrations of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC) and free carbon dioxide (CO2) are presented for a small acidic headwater stream in NE Scotland, Chloride is used as a conservative element to estimate additional, diffuse inputs of water into the main stem of the stream, other than those from tributaries. Downstream changes in instantaneous carbon fluxes were calculated and then used to estimate losses and gains of carbon within the stream system. Dissolved organic carbon concentrations in the stream ranged from 1,19-6.06 mg l(-1) at its source to a maximum of 10.0-25.3 mg l(-1) as the stream passed through deep peats; DOC concentrations then declined in the lower part of the catchment. DIC concentrations were initially low, increased to 1.5-3.0 mg l(-1) and then decreased to 0.1-1.65 mg l(-1) at the lowest site. Free CO2 concentrations increased from 0.35 mg l(-1) at the stream source to 3.30 mg l(-1) as the stream passed through the peat dominated area. Continually high inputs of CO2-rich water (> 6.0 mg l(-1)) from tributaries maintained these high concentrations in the main stem, until approximately 1.74 km downstream when there was a rapid decline in concentration, Significant changes in DOG, DIC and CO2 fluxes occur over a distance of 2.7 km downstream from the stream source to the catchment outlet, Between 5.64-41.5 mg C s(-1) as DOC and 2.52-16.2 mg Cs as DIC are removed from the water column. Between 6.81 and 19.0 mg C s(-1) as CO2 is lost along the stream length as progressive equilibration with the atmosphere occurs. We estimate that 11.6-17.6% of the total DOC flux is removed from streamwater by in-stream processes. Dissolved inorganic carbon(HCO3- and free CO2) losses are in excess of nine times its measured flux at the outlet of the catchment. These results suggest that in-stream processing of DOC and DIC and outgassing of CO2 are important controls on the spatial variability of carbon fluxes within headwater streams in upland catchments dominated by organic-rich soils. (C) 2001 Elsevier Science B.V. All rights reserved.

    Original languageEnglish
    Pages (from-to)153-167
    Number of pages14
    JournalScience of the Total Environment
    Volume265
    DOIs
    Publication statusPublished - 2001

    Keywords

    • carbon
    • catchment
    • spatial changes
    • dissolved organic carbon
    • free CO2
    • in-stream processing
    • DISSOLVED ORGANIC-MATTER
    • FRESH-WATER ECOSYSTEMS
    • UPLAND CATCHMENT
    • RIVER WATER
    • DIOXIDE
    • CO2
    • MECHANISMS
    • ALKALINITY
    • CHEMISTRY
    • SCOTLAND

    Cite this

    Is in-stream processing an important control on spatial changes in carbon fluxes in headwater catchments. / Dawson, Julian James Charles; Bakewell, C.; Billett, M. F.

    In: Science of the Total Environment, Vol. 265, 2001, p. 153-167.

    Research output: Contribution to journalArticle

    Dawson, Julian James Charles ; Bakewell, C. ; Billett, M. F. / Is in-stream processing an important control on spatial changes in carbon fluxes in headwater catchments. In: Science of the Total Environment. 2001 ; Vol. 265. pp. 153-167.
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    abstract = "Data on small-scale spatial variations in instantaneous fluxes and concentrations of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC) and free carbon dioxide (CO2) are presented for a small acidic headwater stream in NE Scotland, Chloride is used as a conservative element to estimate additional, diffuse inputs of water into the main stem of the stream, other than those from tributaries. Downstream changes in instantaneous carbon fluxes were calculated and then used to estimate losses and gains of carbon within the stream system. Dissolved organic carbon concentrations in the stream ranged from 1,19-6.06 mg l(-1) at its source to a maximum of 10.0-25.3 mg l(-1) as the stream passed through deep peats; DOC concentrations then declined in the lower part of the catchment. DIC concentrations were initially low, increased to 1.5-3.0 mg l(-1) and then decreased to 0.1-1.65 mg l(-1) at the lowest site. Free CO2 concentrations increased from 0.35 mg l(-1) at the stream source to 3.30 mg l(-1) as the stream passed through the peat dominated area. Continually high inputs of CO2-rich water (> 6.0 mg l(-1)) from tributaries maintained these high concentrations in the main stem, until approximately 1.74 km downstream when there was a rapid decline in concentration, Significant changes in DOG, DIC and CO2 fluxes occur over a distance of 2.7 km downstream from the stream source to the catchment outlet, Between 5.64-41.5 mg C s(-1) as DOC and 2.52-16.2 mg Cs as DIC are removed from the water column. Between 6.81 and 19.0 mg C s(-1) as CO2 is lost along the stream length as progressive equilibration with the atmosphere occurs. We estimate that 11.6-17.6{\%} of the total DOC flux is removed from streamwater by in-stream processes. Dissolved inorganic carbon(HCO3- and free CO2) losses are in excess of nine times its measured flux at the outlet of the catchment. These results suggest that in-stream processing of DOC and DIC and outgassing of CO2 are important controls on the spatial variability of carbon fluxes within headwater streams in upland catchments dominated by organic-rich soils. (C) 2001 Elsevier Science B.V. All rights reserved.",
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    AU - Dawson, Julian James Charles

    AU - Bakewell, C.

    AU - Billett, M. F.

    PY - 2001

    Y1 - 2001

    N2 - Data on small-scale spatial variations in instantaneous fluxes and concentrations of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC) and free carbon dioxide (CO2) are presented for a small acidic headwater stream in NE Scotland, Chloride is used as a conservative element to estimate additional, diffuse inputs of water into the main stem of the stream, other than those from tributaries. Downstream changes in instantaneous carbon fluxes were calculated and then used to estimate losses and gains of carbon within the stream system. Dissolved organic carbon concentrations in the stream ranged from 1,19-6.06 mg l(-1) at its source to a maximum of 10.0-25.3 mg l(-1) as the stream passed through deep peats; DOC concentrations then declined in the lower part of the catchment. DIC concentrations were initially low, increased to 1.5-3.0 mg l(-1) and then decreased to 0.1-1.65 mg l(-1) at the lowest site. Free CO2 concentrations increased from 0.35 mg l(-1) at the stream source to 3.30 mg l(-1) as the stream passed through the peat dominated area. Continually high inputs of CO2-rich water (> 6.0 mg l(-1)) from tributaries maintained these high concentrations in the main stem, until approximately 1.74 km downstream when there was a rapid decline in concentration, Significant changes in DOG, DIC and CO2 fluxes occur over a distance of 2.7 km downstream from the stream source to the catchment outlet, Between 5.64-41.5 mg C s(-1) as DOC and 2.52-16.2 mg Cs as DIC are removed from the water column. Between 6.81 and 19.0 mg C s(-1) as CO2 is lost along the stream length as progressive equilibration with the atmosphere occurs. We estimate that 11.6-17.6% of the total DOC flux is removed from streamwater by in-stream processes. Dissolved inorganic carbon(HCO3- and free CO2) losses are in excess of nine times its measured flux at the outlet of the catchment. These results suggest that in-stream processing of DOC and DIC and outgassing of CO2 are important controls on the spatial variability of carbon fluxes within headwater streams in upland catchments dominated by organic-rich soils. (C) 2001 Elsevier Science B.V. All rights reserved.

    AB - Data on small-scale spatial variations in instantaneous fluxes and concentrations of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC) and free carbon dioxide (CO2) are presented for a small acidic headwater stream in NE Scotland, Chloride is used as a conservative element to estimate additional, diffuse inputs of water into the main stem of the stream, other than those from tributaries. Downstream changes in instantaneous carbon fluxes were calculated and then used to estimate losses and gains of carbon within the stream system. Dissolved organic carbon concentrations in the stream ranged from 1,19-6.06 mg l(-1) at its source to a maximum of 10.0-25.3 mg l(-1) as the stream passed through deep peats; DOC concentrations then declined in the lower part of the catchment. DIC concentrations were initially low, increased to 1.5-3.0 mg l(-1) and then decreased to 0.1-1.65 mg l(-1) at the lowest site. Free CO2 concentrations increased from 0.35 mg l(-1) at the stream source to 3.30 mg l(-1) as the stream passed through the peat dominated area. Continually high inputs of CO2-rich water (> 6.0 mg l(-1)) from tributaries maintained these high concentrations in the main stem, until approximately 1.74 km downstream when there was a rapid decline in concentration, Significant changes in DOG, DIC and CO2 fluxes occur over a distance of 2.7 km downstream from the stream source to the catchment outlet, Between 5.64-41.5 mg C s(-1) as DOC and 2.52-16.2 mg Cs as DIC are removed from the water column. Between 6.81 and 19.0 mg C s(-1) as CO2 is lost along the stream length as progressive equilibration with the atmosphere occurs. We estimate that 11.6-17.6% of the total DOC flux is removed from streamwater by in-stream processes. Dissolved inorganic carbon(HCO3- and free CO2) losses are in excess of nine times its measured flux at the outlet of the catchment. These results suggest that in-stream processing of DOC and DIC and outgassing of CO2 are important controls on the spatial variability of carbon fluxes within headwater streams in upland catchments dominated by organic-rich soils. (C) 2001 Elsevier Science B.V. All rights reserved.

    KW - carbon

    KW - catchment

    KW - spatial changes

    KW - dissolved organic carbon

    KW - free CO2

    KW - in-stream processing

    KW - DISSOLVED ORGANIC-MATTER

    KW - FRESH-WATER ECOSYSTEMS

    KW - UPLAND CATCHMENT

    KW - RIVER WATER

    KW - DIOXIDE

    KW - CO2

    KW - MECHANISMS

    KW - ALKALINITY

    KW - CHEMISTRY

    KW - SCOTLAND

    U2 - 10.1016/S0048-9697(00)00656-2

    DO - 10.1016/S0048-9697(00)00656-2

    M3 - Article

    VL - 265

    SP - 153

    EP - 167

    JO - Science of the Total Environment

    JF - Science of the Total Environment

    SN - 0048-9697

    ER -