Kinetics of nitrate uptake by freshwater algae

Abstract

The kinetics of nitrate(N0, ) uptake, the maximum uptake velocity (V,) and the half-saturation constant (K,), were determined for 18 species of batch-cultured freshwater algae grown without nitrogen limitation. Values of K, ranged from 0.25 to 6.94 p M 1 for Chlorella pyrenoidosa Chick, and Navicula pelliculosa (Breb.) Hilse, respectively. Values of V, ranged from 0.51 to 5.07 p M 1-' h-I for Anabaena A7214 and Nitzschia W-32 O'Kelley, respectively. The mean positive values of K, for Chlorophyta, Cyanophyta and Chrysophyta were 1.89,3.67 and 4.07 p M 1-I, respectively. The mean values of V, for the same phyla were 1.6 1, 1.02 and 2.97 p M 1 h ' lo5 cells1, respectively. The ranges of these kinetic parameters encompass values of kinetic parameters for marine and freshwater species in batch culture, for freshwater algae grown in N-limited chemostats and for natural populations of freshwater phytoplankton. Thus, in spite of variability between species, uptake parameters for both marine and freshwater algae are identical.

Determination of nutrient uptake kinetic parameters: a comparison of methods

“…3A (open circles) where it is seen that the maximal uptake rate is underestimated. Variations of Method 1 were used in earlier studies ( Underhill 1977, Serra et al 1978, Halterman & Toetz 1984, but the method has been used less frequently in recent years. If the time course of disappearance of the limiting nutrient from the medium is nonlinear, then this method should not b e used to determine V,.…”

Recognition of nutrient and light limitation in turbid mixed layers: Three approaches compared in the Parani floodplain (Argentina)

“…Low concentration of dissolved inorganic nitrogen (DIN) is a necessary but insufficient condition for the diagnosis of N limitation, since half-saturation constants for DIN uptake by some algal species and phytoplankton communities can be as low as 2 mg m-3 (Murphy 1980;Halterman and Toetz 1984;Fisher et al 1988). Low DIN can be particularly misleading in the case of shallow and turbid tropicalsubtropical floodplain lakes where warm temperatures and high ratios of sediment surface to lake volume promote high denitrification rates.…”

Seasonal changes in phytoplankton populations and related chemical and physical characteristics in lakes in Loch Vale, Rocky Mountain National Park, Colorado

“…The diatom bloom during a period of rapid flushing rates implies a rapid phytoplankton growth rate. Rapid growth rate, in turn, may have been stimulated by the concurrent two-fold increase in nitrate concentrations, if the nitrate-uptake kinetics of the diatom populations in the Loch Vale lakes are similar to those of freshwater diatoms studied by Halterman and Toetz (1984 Loch, Mag 23, 1983, andJune 5, 13, 20, and27, 1984 Loch, Mag 23, 1983, andJune 5, 13, 20, and27, 1984 Loch, July 3, 17, and 25, and August 15, and 30, 1984 Loch, Julg 3, 17, and 25, and August 15, and 30, 1984 .4…”

“…However, the nitrate concentrations Lewis and Grant (1979) measured in Como Creek were in the range of 1 to 7 ~g/L, more than 2 orders of magnitude less than those in Loch Vale surface waters. Toetz andWindell (1983, andwritten commun., 1984) measured nitrate concentrations in Albion Lake in the Green Lakes system ranging from 45 to 700 ~g/L in the summers of 1983 and 1984, which is a more limited but comparable range to that measured in Loch Vale lakes. Halterman and Toetz (1984) studied the kinetics of nitrate uptake by many freshwater algal species.…”

“…Toetz andWindell (1983, andwritten commun., 1984) measured nitrate concentrations in Albion Lake in the Green Lakes system ranging from 45 to 700 ~g/L in the summers of 1983 and 1984, which is a more limited but comparable range to that measured in Loch Vale lakes. Halterman and Toetz (1984) studied the kinetics of nitrate uptake by many freshwater algal species. They determined that several diatom species had half-saturation coefficients (K ) for nitrate of 2.5 to 7 ~M (micromolar) which were about the maximum fo~ all algal species studied.…”