V. Gentilhomme et P. Raimbault, NITROGEN UPTAKE AND REGENERATION IN A FRO NTAL REGION OF THE ALGERIANCURRENT (WESTERN MEDITERRANEAN-SEA) - NEW EVALUATION OF NEW PRODUCTION, Oceanologica acta, 17(5), 1994, pp. 555-562
The uptake and regeneration of four forms of nitrogen NO3-, NO2-, NH4 and urea) have been studied, in the euphotic layer of a frontal area
(Algerian current), in relation with hydrological, chemical and biolog
ical parameters. Ln this area vertical stratification is pronounced; a
deep chlorophyll maximum at the bottom of the euphotic layer is prese
nt. Results show the importance of measuring urea uptake and regenerat
ion in the study of nitrogen cycling, because this component can be re
generated as rapidly as ammonia, and is a source of nitrogen for phyto
plankton. Other results show the oxidation of ammonia to nitrate in th
e euphotic layer, and particularly at the base of this layer. This nit
rification is a source of in situ regenerated nitrate, and could lead
to a wrong estimation of the new production estimation.