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The significance of organic carbon and nutrient export from peatland-dominated landscapes subject to disturbance
S. Waldron1, H. Flowers2, C. Arlaud3, C. Bryant4, and S. McFarlane2
1Department of Geographical and Earth Sciences, Univ. of Glasgow, Glasgow G12 8QQ, UK
2Department of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK
3Ecole Nationale Superieure Agrronomique de Toulouse, 31326 Castanet-Tolosan, France
4NERC Radiocarbon Lab, Scottish Enterprise Technology Park, East Kilbride G75 0QF, UK
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Abstract. The terrestrial-aquatic interface is a crucial environment in which to
consider the fate of exported terrestrial carbon in the aquatic system. To a
large extent the fate of dissolved organic carbon (DOC) may be controlled by
nutrient availability. However, peat-dominated headwater catchments are
normally considered of low nutrient status and thus there is little data on
the interaction of DOC and nutrients. Here we present nutrient and DOC data
exported from two UK catchments, both dominated by peat headwaters, but of
differing land-use. Glen Dye is a moorland with no trees; Whitelee has
partially forested peats and peaty podzols, and is now undergoing
development to host Europe's largest on-shore windfarm, the Whitelee
Windfarm. There are significant linear relationships between DOC and soluble
reactive phosphorus and nitrate concentrations in the drainage waters, but
inter-catchment differences exist. Changes in the pattern of nutrient and
carbon export in Whitelee suggest that disturbance of peatlands soils can
impact the receiving water and that nutrient export does not increase in a
stoichiometric manner that will promote increase in biomass. As such the
changes are more likely to cause increased aquatic respiration, and thus
lead to higher dissolved CO2 concentrations (and therefore CO2
efflux). Hence disturbance of terrestrial carbon stores may also impact the
gaseous carbon cycle. Confirming the source of carbon and nutrients in these
study sites is not possible. However, nearby 14C measurements are in
keeping with other published literature values from similar sites which show
C in DOM exported from peatlands is predominantly modern, and thus supports
an interpretation that nutrients, additional to carbon, are derived from
shallow soils. Estimates of organic carbon loss from Whitelee catchments to
the drainage waters suggest a system where losses are approaching likely
sequestration rates. We suggest such sequestration assessment should inform
the decision-making tools required prior to development of terrestrial
carbon stores.
Discussion Paper (PDF, 1134 KB) Interactive Discussion (Final Response, 4 Comments)
Citation: Waldron, S., Flowers, H., Arlaud, C., Bryant, C., and McFarlane, S.: The significance of organic carbon and nutrient export from peatland-dominated landscapes subject to disturbance, Biogeosciences Discuss., 5, 1139-1174, 2008. Bibtex EndNote Reference Manager
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