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The Nitrogen Uptake Kinetics of Spartina Alterniflora in Culture
Author(s) -
Morris James T.
Publication year - 1980
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1936831
Subject(s) - spartina alterniflora , edaphic , nitrogen , saturation (graph theory) , nutrient , spartina , environmental chemistry , botany , ecology , chemistry , marsh , zoology , biology , wetland , soil water , mathematics , organic chemistry , combinatorics
Rates of nitrogen uptake were measured in cultures of Spartina alterniflora growing outdoors in continuously flowing nutrient solutions. A Michaelis—Menten model with V m a x expressed as an exponential function of temperature was an accurate predictor of uptake rates during the growing season. Half—saturation constants were estimated to be 0.057 @+ 0.016 mg N/L for NH 4 and 0.124 @+ 0.034 mg N/L for NO 3 . These half—saturation constants are too low in comparison to levels of inorganic NH 4 in marsh pore water to account for nitrogen—limited growth in the field. It was suggested that an edaphic factors(s), possibly an oxygen deficiency, or a metabolic poison such as H 2 S, or competition from other ions for carriers, might inhibit nitrogen uptake in the marsh in such a way as to increase the half—saturation constant for uptake. A gradient of such an environmental factor could account for gradients in morphology and productivity in communities of Spartina alterniflora.