Inter-Research
Aquatic Microbial Ecology

ABSTRACT: A mathematical computer model describing mineralization processes and transport of solutes within sediments was developed based on the degradation of organic matter, stoichiometrically coupled to the consumption of O₂ in the oxic layers, and to NO₃^- and SO₄^2- in the anoxic layers. The reaction rates obey Michaelis-Menten type kinetics and all transport of solutes is assumed to take place by diffusion. The model was tested on a northeastern Greenland sediment and gave accurate simulations of the measured concentration profiles. In addition, measured processes of nitrification, coupled nitrification-denitrification, denitrification of water column NO₃^-, NH₄⁺ mineralization and the fluxes of NH₄⁺ and NO₃^- across the sediment-water interface were predicted with great accuracy. Since the model is based on Michaelis-Menten type kinetics and diffusional transport mechanisms, it is of general use and provides an important tool to evaluate the regulation of biogeochemical cycling in sediments. This is shown in a series of simulations predicting the effect of various concentrations in the water column of O₂ and NO₃^- on the rates of nitrification and denitrification. The results are in good agreement with previously published measurements.

KEY WORDS: Nitrogen · Mineralization · Modelling · Denitrification · Pore water

Published in AME Vol. 11, No. 3 (1996) on December 31
Print ISSN: 0948-3055; Online ISSN: 1616-1564. Copyright © Inter-Research, Oldendorf/Luhe, 1996