PATTERN AND KINETICS OF NI'l'R1\TE AND AMMONIA UPTAKE IN COASTAL MEDITERRANEAN WATERS IN FRONT OF ALEXANDRIA.

PATTERN AND KINETICS OF NI’l’R1\TE AND AMMONIA UPTAKE IN
COASTAL MEDITERRANEAN WATERS IN FRONT OF ALEXANDRIA.
M.I. EL-SAMRA AND TH. MAHMOUD.
National Institute of Oceanography and Fisheries, Alex.
Egy~~.
ADS’l’MCT
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Uptake of nitrate and ammonia in coastal Mediterranean
waters in front of Alexandria was affected lnainly by the
nitrogen input from land sources. Nutrient uptake cculd be
described by Michaelis-Menten model in areas of nitrogen
content less than 5 ug at NIL and chlorophyll “a”
concentration higher than 15 ug/l. Half saturation constant
Km for nitrate uptake ranged from 2.8 to 27.2 ug at/l while
that for ammonia ranged from 3.7 to 6].9 ug at/l.
Variations of Km values were found to depend on th~ areas
characterized by high nutrient concentrations, the rate of
nutrient uptake v remained coastant, while in areas of low
nutrient v increased steeply by increasing the ambient
concentration of substrate S. The effect of light on
nutrients uptake was discussed.