『Abstract
　Denitrification rates and nitrous oxide (N2O) effluxes were measured at different temperatures and for different oxygen concentrations in the sediments of a eutrophied river entering the Bothnian Bay. The experiments were made in a laboratory microcosm with intact sediment samples. ¹⁵N-labelling was used to measure denitrification rates (Dw). The rates were measured at four temperatures (5, 10, 15 and 20℃) and with three oxygen inputs (＜0.2, 5 and 10 mg O2 l^-1). The temperature response was highly affected by oxygen concentration. At higher O2 concentrations (5 and 10 mg O2 l^-1) a saturation over 10℃ was observed, whereas the anoxic treatment (＜0.2 mg O2 l^-1) showed an exponential increase in the temperature interval with a Q10 value of 3.1. The result is described with a combined statistical model. In contrast with overall denitrification, the N2O effluxes from sediments decreased with increasing temperature. The N2O effluxes had a lower response to oxygen than denitrification rates. The N2O/N2 ratio was always below 0.02. Increased temperatures in the future could enhance denitrification rates in boreal river sediments but would not increase the amount of N2O produced.

Keywords: Baltic Sea; Denitrification and nitrous oxide effluxes; ¹⁵N; Oxygen concentration; River sediments; Temperature』

Introduction
Material and methods
　Site description
　Annual variation in temperatures and oxygen concentrations of the river Temmesjoki
　Sampling and experimental set-up
　Analyses of N2, N2O and DIC
　Oxygen, redox, and pH measurements
　Model for combining O2 concentration and temperature responses of denitrification
Results
　Denitrification rates
　N2O effluxes and N2O/N2 ratio
　DIC effluxes, oxygen consumption, redox potential, and pH
Discussion
　Denitrification rates as affected by temperature
　Temperature effect on N2O effluxes - inhibition on the N2O reductase at low temperatures
　Impact of oxygen availability on denitrification rates and N2O effluxes
Conclusions
Acknowledgements
References