11:30 AM - 11:45 AM
[ACG42-04] Very low δ15N of atmospheric nitrate found in the earstern equatorial Pacific and its implication to dynamic nitrogen recycle between ocean and lower atmosphere
Keywords:Nitrate, Stable Isotopes, Pacific Ocean, Equatorial Pacific
We found remarkably low δ15N(NOx) values for the equatorial Pacific regions compared to those in other regions over Pacific Ocean. These low source δ15N(NOx) values cannot be explained using conventional NOx apportionment. Given that the eastern equatorial Pacific is one of the biologically active ocean regions resulted from upwelling water, here we postulate the alternative biogenic nitrogen source (NH3 or alkyl nitrate) in this region. In the presentation, we will discuss important feature of self-recycle process of nitrogen between ocean and lower atmosphere in the eastern equatorial Pacific. We will also discuss its implication to nitrogen deposition for this region, which may contribute to new marine biological production and/or nitrous oxide emissions.