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| Titel |
Use of geomorphic, hydrologic, and nitrogen mass balance data to model ecosystem nitrate retention in tidal freshwater wetlands |
| VerfasserIn |
E. D. Seldomridge, K. L. Prestegaard |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 7 ; Nr. 9, no. 7 (2012-07-19), S.2661-2672 |
| Datensatznummer |
250007191
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| Publikation (Nr.) |
 copernicus.org/bg-9-2661-2012.pdf |
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| Zusammenfassung |
| Geomorphic characteristics have been used as scaling parameters to predict water and other fluxes
in many systems. In this study, we combined geomorphic analysis with in-situ mass balance studies
of nitrate retention (NR) to evaluate which geomorphic scaling parameters
best predicted NR in a tidal freshwater wetland ecosystem. Geomorphic
characteristics were measured for
267 individual marshes that constitute the freshwater tidal wetland ecosystem of the Patuxent
River, Maryland. Nitrate retention was determined from mass balance measurements conducted at the
inlets of marshes of varying size (671, 5705, and 536 873 m2) over a period of several
years. Mass balance measurements indicate that NR is proportional to total water flux over the
tidal cycle. Relationships between estimated tidal prism (calculated water volume) for spring tides and
various geomorphic parameters (marsh area, total channel length, and inlet
width) were defined using measurements from air photos and compared to field
data. From these data, NR equations were determined for each geomorphic
parameter, and used to estimate NR for all marshes in the ecosystem for
a reference spring (high) tide. The resulting ecosystem NR estimates were
evaluated for (a) accuracy and completeness of
geomorphic data, (b) relationship between the geomorphic parameters and hydrologic flux, and (c)
the ability to adapt the geomorphic parameter to varying tidal conditions. This analysis indicated
that inlet width data were the most complete and provided the best estimate of ecosystem nitrate
retention. Predictions based on marsh area were significantly lower than the inlet width-based
predictions. Cumulative probability distributions of nitrate retention indicate that the largest
3–4% of the marshes retained half of the total nitrate for the ecosystem. |
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