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| Titel |
DOC export from a peat extraction site in transition to managed restoration - preliminary results of a long-term research project |
| VerfasserIn |
Norman Rüggen, Lars Kutzbach, Susanne Kopelke, Eva-Maria Pfeiffer |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250084099
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| Zusammenfassung |
| Peatlands play a major role in the global cycles of water and carbon. Budgeting carbon fluxes
of temperate man-managed peatlands is limited by few available data. The main carbon
compounds exported from such sites are CO2, CH4 and laterally exported C compounds
(dissolved organic carbon (DOC) and gases). Without reliable estimates of laterally exported
carbon from managed peatlands, overall carbon balances of such geoecosystems remain
obscure.
The Himmelmoor peatland in Schleswig-Holstein is subject to horticultural peat extraction in
transition towards managed restoration. One-third of 130 ha of peatland area are already
subject to managed restoration, the remaining part is still intensively used as a peat extraction
site. Surface water discharge rates are measured by a water head sensor in combination with a
rectangular-shaped weir. An October-November data set (54 days period, 2012) shows a
distinct base-flow and precipitation-dependent discharge peaks, which were up to five times
higher than the base-flow. The observations indicate a poor water storing capacity
of the intensively used areas. During this first observation period, almost 65,000
tons of peatland-DOC-bearing water have been discharged into the adjacent river
system. DOC concentrations in the discharge water have been measured every 6-12
days with a Total Carbon Analyzer TOC-L (Shimadzu, Japan). Additionally, a field
spectrophotometer (spectro::lyser,s-can, Austria) has been employed, for measuring
quasi-continuous concentrations of DOC. During the 54 day period, approximately 1.75 g
DOC m-2 (or about 1750 kg DOC km-2) has been laterally exported from the
peatland. Average DOC concentration was 35.1 ± 4 g l-1. These values range in the
same order of magnitude that have been published from managed UK peatlands
(Armstrong et al., 2010; Wilson et al., 2011). Preliminary data evaluation of the
in-situ field spectrophotometer show that DOC concentrations of discharge water
varied up to 1.5 mg L-1 in less than six hours and up to about 3 mg L-1 in 36
hours.
The described recently established hydrological measurements are planned to be continued
for the next ten years in combination with continuous eddy covariance measurements of
land-atmosphere fluxes of Water, CO2 and CH4. This long-term monitoring of lateral
and vertical exchange fluxes will serve as a basis for evaluating the success of the
peatland restoration with respect to biogeochemical cycling and greenhouse gas
budgets.
Literature
Armstrong, A., Holden, J., Kay, P., Francis, B., Foulger, M., Gledhill, S., McDonald, A.,
Walker, A., 2010. The impact of peatland drain-blocking on dissolved organic carbon loss
and discolouration of water; results from a national survey. Journal of Hydrology 381,
112–120.
Wilson, L., Wilson, J., Holden, J., Johnstone, I., Armstrong, A., Morris, M., 2011. Ditch
blocking, water chemistry and organic carbon flux: Evidence that blanket bog restoration
reduces erosion and fluvial carbon loss. Science of the Total Environment 409, 2010–2018. |
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