 |
| Titel |
Dissimilatory Nitrate Reduction to Ammonium (DNRA) potential in the re-connected floodplain of the River Cole (Oxfordshire, UK). |
| VerfasserIn |
F. Sgouridis, C. M. Heppell, M. Trimmer, G. Wharton |
| Konferenz |
EGU General Assembly 2009
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250024360
|
|
|
|
|
|
| Zusammenfassung |
| Floodplains are recognised as an important interface for nitrate removal at the landscape
scale, but there is a lack of available information on the nitrate attenuation capacity of
reconnected floodplains following river restoration. Whilst numerous studies have
documented the dominant role of heterotrophic denitrification for nitrate loss in these
environments, DNRA, a microbial pathway that conserves N in the ecosystem, has
previously been considered unimportant in aerobic floodplain soils due mainly to its
anoxic nature (Tiedje, 1988). However, recent research has shown DNRA to be
of importance in N-limited, redox fluctuating tropical soils (Silver et al., 2001,
Huygens et al., 2007). This could potentially be important in the context of temperate
intermittently saturated reconnected river floodplains designed to tackle diffuse nitrate
pollution. Therefore the objectives of this research were to quantify (i) the magnitude of
and; (ii) factors controlling DNRA and denitrification potential in four different
land use zones (grazing grassland, buffer zone, pasture and fritillary meadow), and
with depth (0 – 120 cm) in a re-connected rural floodplain of the River Cole, UK.
Denitrification and DNRA potential rates were measured with a combination of
15NO3- isotope tracer addition and combined microdiffusion - hypobromite oxidation
methods.
DNRA potential rates were approximately 40times less than denitrification potential
rates, in all samples, ranging from 0.02 – 2.64 mg N and 7 – 24 mg N Kg-1 of dry soil day-1
respectively. Denitrification potential rates were found to be significantly different (P |
|
|
|
|
|
|