Investigating Local Sources of Ammonia in the Arctic

Arctic ecosystems are believed to be nutrient-limited, thus highly influenced by deposition of reactive nitrogen from the atmosphere, such as ammonia (NH3). This proposal investigates ammonia in the Ny-Alesund region, to better quantify local sources of this nutrient, in the context of changes and variability indicated by Zeppelin monitoring data. In Svalbard, reactive nitrogen species nitrate NO3- and ammonium NH4+ are deposited in precipitation following long-range transport from European industrial and agricultural sources regions. However, sources of reactive nitrogen in the form of ammonia (e.g. from bird guano, sewage) are likely also important locally. Such ecological impacts are visually apparent in Ny-Alesund through ‘greening’ around bird-cliffs in summer, with enhanced NH4+ also observed in summer precipitation (NILU data). Daily air and aerosol observations of reactive nitrogen at Mt Zeppelin indicate influences from both long-range transport and local sources. Observed NH3 shows seasonality, and a recent increase, which might be due to changing local sources and boundary-layer stability, although these observations are poorly constrained due to limited data. As any change in local NH3 emission or dispersion could significantly impact Ny-Alesund ecosystems, I propose field-measurements (collaboration CEH-UK) to investigate sources and spatial distribution of NH3 and NH4 in Ny-Alesund, investigating both sources from guano under bird-cliffs, potential sources from sewage, and spatial extent of NH3 and NH4+ in the region including vertical spread up to Mt Zeppelin. Findings will be placed in the context of 20-year monitoring records of ammonia(um) in Ny-Alesund/Zeppelin (NILU collaboration) and will connect to ongoing NSINK investigations into reactive nitrogen in daily precipitation (R. Kuhnel), deposition in the snowpack (M. Bjorkman), and soil microbial processes (F.Oulehle).