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| Titel |
The role of the benthic-hyporheic zone in controlling nitrous oxide emissions along two stream networks draining watersheds with contrasting land use |
| VerfasserIn |
Alessandra Marzadri, Martha M. Dee, Daniele Tonina, Jennifer L. Tank, Alberto Bellin |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250131282
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| Publikation (Nr.) |
 EGU/EGU2016-11673.pdf |
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| Zusammenfassung |
| Nitrous oxide (N2O) is a potent greenhouse gas responsible of stratospheric ozone
destruction. Denitrification in stream ecosystems occurs within the benthic layer at the
sediment-water interface and within subsurface environments such as the hyporheic zone and
results in N2O production that could be eventually emitted to the atmosphere. Here, we
quantify the role of benthic and hyporheic zones as sources of N2O gas and explore the
dependence of emissions from stream morphology, flow hydraulics, land use and climate
using a recently-developed fully analytical framework. Variations in N2O emissions
within and among catchments of contrasting land use can be explained with a new
denitrification Damköhler number (DaD) that accounts for denitrification processes
within both benthic and hyporheic zones. For initial model development, we found
a strong relationship between DaD and stream N2O emissions using field data
collected from multiple headwater streams (i.e., LINXII project) from different
biomes draining contrasting land use. We then tested its generality by comparing
N2O emissions predicted with DaD to those measured using a synoptic sampling
campaign in two stream networks draining contrasting land use: Manistee R (Michigan,
USA) and Tippecanoe R (Indiana, USA). Our dimensionless analysis shows that
the effect of land use disappears after making the emissions dimensionless with
respect to the nitrogen load. Reliable predictions of N2O emissions at the stream
network scale can be obtained from a limited amount of information, consisting
in relatively easy to obtain biogeochemical and hydromorphological quantities. |
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