Prise simultanee de quatre sources d'azote par le microphytobenthos du chenal de Lauzieres (Charente Maritime-France) en ete

Simultaneous uptake of nitrate, nitrite, ammonium and urea by microphytobenthos incubated in batch mode immediately after sampling do not show any kind of interactions. A linear relationship is found between nitrate uptake and ammonium uptake, the latter values being about 2 to 3 times higher than former. Ammonium uptake was not saturated by a substrate level of 10 mu M, possibly indicating diffusion limited uptake. For all nitrogen sources, the uptake rate was related to the substrate concentration rather than the oxidation state of the nitrogen compounds.