MEPS 172:13-24 (1998)  -  doi:10.3354/meps172013

Spatial and temporal variability of denitrification in the sediments of the northern Baltic Proper

Liisa Tuominen1,*, Anne Heinänen1,**, Jorma Kuparinen1, Lars Peter Nielsen2

1Finnish Institute of Marine Research, PO Box 33, FIN-00931 Helsinki, Finland
2Department of Microbial Ecology, Institute of Biological Sciences, University of Aarhus, Ny Munkegade, Building 540, DK-8000 Aarhus C, Denmark
*E-mail:
**Present address: Academy of Finland, PO Box 99, FIN-00501 Helsinki, Finland

ABSTRACT: Denitrification in the sediments of the open northern Baltic Sea was measured using the isotope pairing method. The highest denitrification activity was found in the central Gulf of Finland, where denitrification varied between 150 and 650 µmol N m-2 d-1. The bulk of the denitrification was coupled to the NO3- production by nitrification. The mass of benthic fauna was found to be the most significant factor affecting the rate of denitrification. Denitrification rate was highest in late summer and early autumn. Calculated as an average for the Gulf of Finland, the denitrification rate obtained in the present study is 45 kt N yr-1. This gives a release of ca 30% of the external N input by denitrification.


KEY WORDS: Denitrification · Baltic Sea · Isotope pairing method · Sediment


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