University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Master / Diploma Thesis:
Alexandra Tiefenbacher
(2015):
Impact of long-term nitrogen deposition on greenhouse-gas emissions of an ombrotrophic bog in Scotland.
Master / Diploma Thesis - Institut für Bodenforschung (IBF),
BOKU-Universität für Bodenkultur,
pp 77.
UB BOKU
obvsg
- Abstract:
- The aim of this master thesis was to estimate potential greenhouse gas (GHG) flux rates coming from soil and litter of a nitrogen (N) fertilized ombrotrophic peatland. Additionally, the possible influence of climate change was assessed by measuring GHG flux rates at varying soil temperatures. Emission measurements of nitric oxide (NO), nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) were conducted under controlled laboratory conditions using intact soil cores and litter samples from the Whim Bog site. Since 2002, the Whim Bog in Scotland has offered a globally unique field simulation of reactive N deposition as dry deposited ammonia and wet deposited reduced N and oxidized N added as ammonium chloride and sodium nitrate, respectively. In addition, all nitrogen deposition types were analyzed within two concentrations, namely 32 kg N ha-1 y-1 and 64 kg N ha-1 y-1. We found a distinct and specific effect of nitrogen deposition type on all observed GHG gas fluxes; furthermore, the concentration affected GHG differently and depended upon the fertilizer type and sample material. Compared to control plots, ammonia fertilization enhanced NO emissions from soils samples, whereas CO2 emissions were lowered. Moreover, the temperature response of GHG emissions changed with fertilization type. Compared to control plots, any type of fertilization had a potential climate warming effect through enhanced greenhouse gas release from soil and litter, which was mainly caused by increased NO, N2O and CH4 emissions. The highest global warming potential (GWP) was calculated for plots fertilized with ammonia, whereas the lowest could be detected at non-fertilized plots. We conclude direct or indirect (via wind drift) anthropogenic deposition of nitrogen fertilizer have a significant impact on greenhouse gas emissions; this is a relevant issue for current air pollution policy.
- Beurteilende(r): Zechmeister-Boltenstern Sophie