AMMONIUN AND NITRATE UPTAKE BY THE MARINE MACROPHYTES HYPNEA MUSVUFORMIS (RHODOPHYTA) AND MACROCYSTIS PYRIFERA (PHAEOPHYTA)1, 2 |
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Authors: | Kenneth C. Haines Patricia A. Wheeler |
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Abstract: | NH4+ and NO3? uptake were measured by continuous sampling with an autoanalyzer. For Hypnea musciformis (Wulfen) Lamouroux, NO3?up take followed saturable kinetics (K2=4.9 μg-at N t?1, Vmax= 2.85 μg- at N, g(wet)?1. h?1. The ammonium uptake data fit a trucatd hyperbola, i.e., saturation was not reach at the concentrations used. NO3? uptake was reduced one-half in the presence of NH4+, but presence of NO3? had no effect on NH4+ uptake. Darkness reduced both NO3? and NH4+ uptake by one-third to one-half. For Macrocystis pyrufera (L) C. Agardh, NO3? uptake followed saturable kinetices: K2=13.1 μg-at N. l?1. Vmax=3.05 μg-at N. g(wet)?1. h?1.NH4+ uptake showed saturable kinetics at concentration below 22 μg-at N l -1 (K2=5.3 μg-at N.1–1, Vmax= 2.38 μg-at N G (wet)?1.h?1: at higher concentration uptake increased lincarly with concentrations. NO3?and NH4+ were taken up simulataneously: presence of one form did not affect uptake of the other. |
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Keywords: | ammonium Hypnea Macrocystis nitrate uptake kinetics |
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