title: Nitrification in the Schelde estuary: methodological aspects and factors influencing its activity.
abstract: Abstract We present a 15-month dataset on nitrification measurements in the Schelde estuary (Belgium and The Netherlands). Nitrification was estimated using the N-serve sensitive dark (14)C-bicarbonate incorporation technique. A peak of nitrification activity was observed in the freshwater part of the estuary. Downstream from this peak, nitrification declined, probably because of ammonium limitation. A range of nitrification inhibitors was tested on both a Nitrosomonas europaea culture and estuarine samples. It was found that methyl fluoride and acetylene stimulated dark (14)C-bicarbonate incorporation and those inhibitors were therefore considered inappropriate nitrification inhibitors in combination with this technique. The effect of the inhibitor N-serve was studied on the dark incorporation of (13)C-bicarbonate into polar lipid derived fatty acids to further identify the dominant chemoautotrophic processes. Inhibition of polar lipid derived fatty acid labelling in the presence of N-serve was complete, suggesting that nitrifying bacteria dominated the chemoautotrophic community.
authors.affiliation: Netherlands Institute of Ecology, Centre for Estuarine and Coastal Ecology, P.O. Box 140, NL-4400 AC Yerseke, The Netherlands.
authors.forename: Monique J M
authors.initials: MJ
authors.lastname: Bie
authors.forename: Mathieu
authors.initials: M
authors.lastname: Starink
authors.forename: Henricus T S
authors.initials: HT
authors.lastname: Boschker
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Peene
authors.forename: Hendrikus J
authors.initials: HJ
authors.lastname: Laanbroek