Change search
ReferencesLink to record
Permanent link

Direct link
Eddy covariance flux measurements confirm extreme CH(4) emissions from a Swiss hydropower reservoir and resolve their short-term variability
ETH Zurich, Institute of Agricultural Sciences.
Eawag, Swiss Federal Institute of Aquatic Science and Technology.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
2011 (English)In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 8, no 9, 2815-2831 p.Article in journal (Refereed) Published
Abstract [en]

Greenhouse gas budgets quantified via land-surface eddy covariance (EC) flux sites differ significantly from those obtained via inverse modeling. A possible reason for the discrepancy between methods may be our gap in quantitative knowledge of methane (CH(4)) fluxes. In this study we carried out EC flux measurements during two intensive campaigns in summer 2008 to quantify methane flux from a hydropower reservoir and link its temporal variability to environmental driving forces: water temperature and pressure changes (atmospheric and due to changes in lake level). Methane fluxes were extremely high and highly variable, but consistently showed gas efflux from the lake when the wind was approaching the EC sensors across the open water, as confirmed by floating chamber flux measurements. The average flux was 3.8 +/- 0.4 mu g C m(-2) s(-1) (mean +/- SE) with a median of 1.4 mu g C m(-2) s(-1), which is quite high even compared to tropical reservoirs. Floating chamber fluxes from four selected days confirmed such high fluxes with 7.4 +/- 1.3 mu g C m(-2) s(-1). Fluxes increased exponentially with increasing temperatures, but were decreasing exponentially with increasing atmospheric and/or lake level pressure. A multiple regression using lake surface temperatures (0.1 m depth), temperature at depth (10 m deep in front of the dam), atmospheric pressure, and lake level was able to explain 35.4% of the overall variance. This best fit included each variable averaged over a 9-h moving window, plus the respective short-term residuals thereof. We estimate that an annual average of 3% of the particulate organic matter (POM) input via the river is sufficient to sustain these large CH(4) fluxes. To compensate the global warming potential associated with the CH(4) effluxes from this hydropower reservoir a 1.3 to 3.7 times larger terrestrial area with net carbon dioxide uptake is needed if a European-scale compilation of grass-lands, croplands and forests is taken as reference. This indicates the potential relevance of temperate reservoirs and lakes in local and regional greenhouse gas budgets.

Place, publisher, year, edition, pages
2011. Vol. 8, no 9, 2815-2831 p.
National Category
Natural Sciences
URN: urn:nbn:se:uu:diva-160527DOI: 10.5194/bg-8-2815-2011ISI: 000295375700029OAI: diva2:451240
Available from: 2011-10-25 Created: 2011-10-25 Last updated: 2015-04-02Bibliographically approved

Open Access in DiVA

Eugster_etal_2011(11732 kB)63 downloads
File information
File name FULLTEXT01.pdfFile size 11732 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Search in DiVA

By author/editor
Sobek, Sebastian
By organisation
In the same journal
Natural Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 63 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 320 hits
ReferencesLink to record
Permanent link

Direct link