Abstract

In 2010 two CEH scientists went to Bird Island via the Collabortive Gearing system to study biosphere-atmosphere interactions. The first scientist, Sim Tang from CEH involved monitoring of ammonia concentrations in order to better constrain the global seabird ammonia emission estimates. As with agricultural systems, the cycling of nitrogen from animal colonies into the atmosphere and subsequent terrestrial deposition are key biosphere-atmosphere interactions. GHG and ecosystem measurements were undertaken to provide an assessment of the impact of ammonia emissions on the island ecosystem and emission of green house gases. Additionally SO2 , HCl, HNO3 and inorganic aerosol composition, rain composition, ozone and CO2 concentrations measurements were made. The final part of study is to extrapolate from the measurements to assess the Bird Island nitrogen budget.

The second scientist Julia Schmale (visiting from MPI , Mainz) studied the biogenic influences on the composition and characteristics of aerosol on Bird Island with an aerosol mass spectrometer. This remote marine environment is characterised by large seabird and seal colonies. The chemical composition of the submicron particleswas 21% non-sea-salt sulfate, 2% nitrate, 8% ammonium, 22% organics and 47% sea salt including sea salt sulfate. A new method to isolate the sea spray signature from the high-resolution AMS data was applied. Generally, the aerosol was found to be less acidic than in other marine environments due to the high availability of ammonia, from local fauna emissions. By positive matrix factorisation five different organic aerosol (OA) profiles could be isolated – the origins of these factors will be discussed in relation to avian activity, longe range transport and phytoplankton blooms int eh South Atlantic.

The studies will be discussed in terms of future research directions. Global, regional and local climate changes can strongly influence the process of nitrogen transport from the ocean to the atmosphere and back onto the land. There is much to be done to fully understand how larger scale changes may influence both air chemistry, GHG emissions, and life in general in remote ecosystems. Future collaboration to work in this area will be discussed.