『Abstract
　This study examined changes in dissolved organic nitrogen (DON) and dissolved inorganic nitrogen (DIN) in coastal seawater after exposure to sand along a high energy beach face over an annual cycle between April 2004 and July 2005. dissolved organic nitrogen, NO3^-, and NH4⁺ were released from sand to seawater in laboratory incubation experiments clearly demonstrating that they are a potential source of N to underlying groundwater or coastal seawater. DON increases in seawater, after exposure to surface sands in laboratory experiments, were positively correlated with in situ water column DON concentrations measured at the same rime as sand collection. Increase in NO3^-, and NH4⁺ were not correlated with their in situ concentrations. This suggests that DON released from beach sands is relatively more recalcitrant while NO3^-, and NH4⁺ are utilized rapidly in the coastal ocean. The release of N was seasonal with carbon to nitrogen ratios indicating that recent primary productivity was responsible for the largest fluxes in summer while more degraded humic material contributed to lower fluxes in winter. Fluxes of total dissolved nitrogen (DON and DIN) from surface sand (2.1×10^-4 mol m^-2 h^-1) were similar to that of groundwater and more than an order of magnitude larger than rain deposition indicating the potential importance of surface sand derived nitrogen to the coastal zone with a corresponding impact on primary productivity.

Keywords: Sandy beach; Dissolved organic nitrogen; Dissolved inorganic nitrogen; Nitrate; Ammonium』

Introduction
Methods
　Sample sites and sampling
　Sediment dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) extraction experiments
　Nitrogen analyses
　DOC analysis
　Chlorophyll analysis
　Calculations
Results and discussion
　Total dissolved nitrogen (TDN)
　Dissolved organic nitrogen
　Nitrate
　Ammonium
Implications
Acknowledgments
References