Related Experiment Video
Updated: Aug 8, 2026

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations
Published on: August 3, 2016
Nitrate Utilization by the Diatom Skeletonema costatum: I. Kinetics of Nitrate Uptake
J L Serra1, M J Llama, E Cadenas
1Departamento de Bioquímica, Facultad de Ciencias, Universidad de Bilbao, Bilbao, Spain.
Abstract:
Nitrate uptake has been studied in nitrogen-deficient cells of the marine diatom Skeletonema costatum. When these cells are incubated in the presence of nitrate, this ion is quickly taken up from the medium, and nitrite is excreted by the cells. Nitrite is excreted following classical saturation kinetics, its rate being independent of nitrate concentration in the incubation medium for nitrate concentration values higher than 3 micromolar. Nitrate uptake shows mixed-transfer kinetics, which can be attributed to the simultaneous contributions of mediated and diffusion transfer. Cycloheximide and p-hydroxymercuribenzoate inhibit the carrier-mediated contribution to nitrate uptake, without affecting the diffusion component. When cells are preincubated with nitrate, the net nitrogen uptake is increased.
More Related Videos
Related Concept Videos
Inorganic Nitrogen Assimilation
Overview of Nitrogen Metabolism
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
Metabolism of Chemolithotrophs
2° Amines to N-Nitrosamines: Reaction with NaNO2

