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| Titel |
Estimating gas exchange of CO2 and CH4 between headwater systems and the atmosphere in Southwest Sweden |
| VerfasserIn |
Celia Somlai, Sivakiruthika Natchimuthu, David Bastviken, Andreas Lorke |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250111425
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| Publikation (Nr.) |
 EGU/EGU2015-11535.pdf |
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| Zusammenfassung |
| Quantifying the role of inland water systems in terms of carbon sinks and sources and their
connection to the terrestrial ecosystems and landscapes is fundamental for improving the
balance approach of regional and global carbon budgets. Recent research showed that
freshwater bodies emit significant amounts of CO2 and CH4 into the atmosphere. The extent
of the emissions from small streams and headwaters, however, remains uncertain due to a
limited availability of data. Studies have shown that headwater systems receive most of the
terrestrial organic carbon, have the highest dissolved CO2 concentration and the highest
gas exchange velocities and cover the largest fractional surface area within fluvial
networks.
The gas exchange between inland waters and the atmosphere is controlled by two factors:
the difference between the dissolved gas concentration and its atmospheric equilibrium
concentration, and the gas exchange velocity. The direct measurement of the dissolved gas
concentration of greenhouse gases can be measured straightforwardly, for example,
by gas chromatography from headspace extraction of water sample. In contrast,
direct measurement of gas exchange velocity is more complex and time consuming,
as simultaneous measurements with a volatile and nonvolatile inert tracer gas are
needed.
Here we analyze measurements of gas exchange velocities, concentrations and
fluxes of dissolved CO2 and CH4, as well as loads of total organic and inorganic
carbon in 10 reaches in headwater streams in Southwest Sweden. We compare
the gas exchange velocities measured directly through tracer injections with those
estimated through various empirical approaches, which are based on modelled and
measured current velocity, stream depth and slope. Furthermore, we estimate the
resulting uncertainties of the flux estimates. We also present different time series of
dissolved CO2, CH4 and O2 concentration, water temperature, barometric pressure,
electro conductivity, and pH values measured during the period of tracer injection. |
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