Inorganic nitrogen uptake by two kelp species, Laminaria solidungula and Laminaria saccharina, in the Alaskan High Arctic ...

• Main Author: Dibble, John Michael
• Format: Text
• Language: English
• Published: The University of Texas at Austin 1995
• Subjects: Nitrogen uptake; Nitrogen fixation; Inorganic nitrate; Ammonium; Kelp; Laminaria solidungula; Laminaria saccharina; Alaska; Beaufort Sea Coast; Laminariales > Alaska > Beaufort Sea Coast; Laminaria saccharina > Alaska > Beaufort Sea Coast; Nitrogen > Fixation > Alaska > Beaufort Sea Coast; Kelps > Alaska > Beaufort Sea Coast; Nitrogen compounds > Alaska > Beaufort Sea Coast; Ammonium > Alaska > Beaufort Sea Coast; Arctic; Beaufort Sea
• Online Access: https://dx.doi.org/10.26153/tsw/47563; https://repositories.lib.utexas.edu/handle/2152/120730

The uptake of inorganic nitrate (NO₃⁻) and ammonium (NH₄⁺) by two co-occurring species of kelp, Laminaria solidungula and Laminaria saccharina, was compared using entire plants incubated under natural conditions in the field and in the laboratory. Field experiments were conducted in situ during ice-covered and open-water periods in the Boulder Patch kelp bed community in the Alaskan Beaufort Sea. The data obtained in these experiments do not provide evidence of Michaelis-Menten saturation kinetics. The uptake of NO₃⁻ and NH₄⁺ by both species appears to be a linear function of substrate concentration with no evidence of a saturating concentration although average substrate concentrations approach 80 μM. There was no significant difference between NO₃⁻ and NH₄⁺ uptake rates in conditions where either NO₃⁻ or NH₄⁺ were supplied at the same concentrations and no significant difference in uptake rates between species. The mean uptake rate at ambient nitrate concentrations in winter (4 - 7 μM) was 0.53 /μmoles ...