Atmospheric water-soluble organic nitrogen (WSON) over marine environments: a global perspective
- 1Environmental Chemistry Processes Laboratory, Department of Chemistry, University of Crete, P.O. Box 2208, 71003 Heraklion, Greece
- 2LSCE, CEA-CNRS-UVSQ, UMR1572 Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvette, France
- 3Max Planck Institute for Chemistry, Air Chemistry Department, 55128 Mainz, Germany
- 4Centre for Ocean and Atmospheric Sciences School of Environmental Sciences, University of East Anglia, Norwich, UK
- 5Institute for Environmental Research and Sustainable Development, National Observatory of Athens, 15236 P. Penteli, Athens, Greece
Abstract. To obtain a comprehensive picture of the spatial distribution of water-soluble organic nitrogen (WSON) in marine aerosols, samples were collected during research cruises in the tropical and southern Atlantic Ocean and also in the southern Indian Ocean (Amsterdam Island) for a 1-year period (2005). Samples were analyzed for both organic and inorganic forms of nitrogen, and the factors controlling their levels were examined. Fine-mode WSON was found to play a significant role in the remote marine atmosphere with enhanced biogenic activity, with concentrations of WSON (11.3 ± 3.3 nmol N m−3) accounting for about 84 % of the total dissolved nitrogen (TDN). Such concentrations are similar to those observed in the polluted marine atmosphere of the eastern Mediterranean (11.6 ± 14.0 nmol N m−3). Anthropogenic activities were found to be an important source of atmospheric WSON as evidenced by the levels in the Northern Hemisphere (NH) being 10 times higher than in the remote Southern Hemisphere (SH). Furthermore, the higher contribution of fine-mode WSON to TDN (51%) in the SH, compared to the NH (13%), underlines the important role of organic nitrogen in remote marine areas. Finally, there was a strong association of WSON with dust in coarse-mode aerosols in the NH.