Deposition, return flux, and burial rates of nitrogen and phosphorus in the sediments of two high-Arctic fjords

Annual deposition to sediments ranged between 2.3-8.3 g m−2 for N and 0.9-2.8 g m−2 for P. The nitrogen return fluxes ranged from 0.12 to 1.46 g m−2 y−1. At most stations, the N flux was predominantly of dissolved organic (about 60-70%) rather than inorganic N. The P return flux varied between 0.01 and 0.11 g m−2 y−1, with organic species constituting 60-97%. The N and P burial rates differed between fjords: 2.3-7.9 g N m−2 y−1 and 0.9-2.8 g P m−2 y−1 in Hornsund vs. 0.9-1.3 N g m−2 y−1 and 1.0-1.2 g P m−2 y−1 in Kongsfjorden. This was accompanied by a different efficiency of N and P burial - higher in Hornsund than in Kongsfjorden, in both cases. This suggests differences in the quality and quantity of N and P organic species deposited to sediments and therefore differences in the intensity of their mineralization and/or decomposition.