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| Titel |
Influence of topographic setting on the geomorphology and subsurface hydrochemistry of northern forested wetlands |
| VerfasserIn |
M. C. Richardson, C. P. J. Mitchell, B. A. Branfireun, R. K. Kolka |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250027915
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| Zusammenfassung |
| Biogeochemical hot spots across upland-wetland ecotones are strongly influenced by upslope
runoff, yet this is often overlooked as a factor affecting landscape-scale biogeochemical
cycling in boreal forest ecosystems. New techniques are therefore required to quantify the
relative contributions of upland-wetland interactions to landscape-scale processes in these
regions, such as carbon cycling and terrestrial-aquatic fluxes of nutrients and contaminants. A
residual analysis of bare earth returns from airborne Light Detection and Ranging (LiDAR)
surveys was therefore conducted to derive characteristic geomorphologies for 14 forested
wetlands in central Ontario, Canada, northwestern Ontario, Canada and northern Minnesota,
USA. Several geomorphic indices were developed including objective quantifications of the
width of the upland-wetland interface zone (LWI), and the slope of the lateral, meso-scale
topographic gradient from wetland-edge to wetland-centre (LSI). At four wetland sites
sampled extensively for near-surface porewater chemistry, there is marked spatial
correlation between the statistical properties of sulphate and methylmercury (MeHg)
concentrations and the LIDAR-derived upland-wetland interface or ‘lagg’area.
Furthermore, the LWI and LSI indices are systematically correlated to a Peatland
Topographic Index (PTI) describing the relative openness of a wetland to inputs from the
surrounding landscape due to upslope contributing area and local drainage conditions
(r2=0.58 and r2=0.64 respectively, p |
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