『Abstract
　Although sediments of the German Wadden Sea are suspected to eliminate a considerable share of nitrate delivered to the SE North Sea, their denitrification rates have not been systematically assessed. We determined N2 production rates over seasonal cycles (February 2009 - April 2010) at two locations with two sediments types each, the first site (Meldorf Bight) receiving nitrate during all seasons from the Elbe river plume, and a second site on the island of Sylt, where nitrate is depleted during summer months. In sediments from the Sylt site, N2 production ranged from 15 to 32μmol N2 m^-2 h^-1 in the fine sand station and from 7 to 13μmol N2 m^-2 h^-1 in the coarse sand station; N2 production was not detected when nitrate was depleted in May and July of 2009. N2 production in the Meldorf Bight sediments were consistently detected at higher rates (58-139μmol N2 m^-2 h^-1 in the very fine sand station and between 14 and 30μmol N2 m^-2 h^-1 in the medium sand station). Analysis of ancillary parameters suggests that major factors controlling N2 production in coastal sediments of the German Wadden Sea are the nitrate concentrations in the overlying water, the ambient temperature, and the organic matter content of the sediment. Extrapolating our spot measurements to the zone of nitrate availability and sediment types, we estimate an annual nitrogen removal rate around 16 kt N year^-1 for the entire northern sector of the German Wadden Sea area. This corresponds to 14% of the annual Elbe river nitrogen load.

Keywords: Denitrification; Nitrogen; Sediments; Wadden Sea; German Bight; Incubation』

Introduction
Materials and methods
　Study site
　Sampling
　Sediment core incubation
　　Core incubations with site water (unamended cores)
　　Core incubation with site water enriched with ¹⁵NO3^- (amended cores)
　Laboratory analyses and rate determinations
　　Determination of actual net N2 and O2 fluxes
　　Calculation of N2 production rates from amended cores according to IPT
　　Nutrient concentrations
　　Sediment characteristics
Results
　Sediment characteristics at the different sites
　Seasonal variation of the site parameters
　Nutrient fluxes
　N2 and O2 fluxes
Discussion
　Insights into N-cycling from nutrient fluxes and denitrification rates obtained by IPT
　Nitrate and temperature effects on N2 production rates in Busum（最初のuの頭に¨） and Sylt sediments
　Influence of sedimentary TOC content
　An estimate of annual nitrogen removal in the northern German Wadden Sea
Conclusions
Acknowledgments
References