Estimating release rates of phosphorus from zooplankton: model and experimental verification
The flux of phosphorus in a zooplankton-phytoplankton system is described by a simple compartment model, with differential equations for grazing, growth and reproduction of animals, and release and recycling of P. The mean release rates from zooplankton for a given period are derived for cases restricted to animals feeding on algae at densities above the incipient limiting food concentration. The model is used to analyze short term incubation experiments with Daphnia pulex feeding on Scenedesmus sp. and Daphnia longispina feeding on Rhodomonas lacustris in dim light. When food organisms were saturated with P. total release rates were in the range 1.1-1.5 ..mu..g P (mg dry wt)/sup -1/h/sup -1/ in accordance with a maximal excretion rate of 0.8 ..mu..g P (mg dry wt)/sup -1/h)/sup 1/ predicted by the model of Peters. Phosphorus-starved phytoplankton, containing less P, gave much lower release rates, about 0.05 ..mu..g P (mg dry wt)/sup -1/h/sup -1/, only 10% of the excretion rate predicted by the model of Peters.
- Research Organization:
- Univ. of Trondheim, Norway
- OSTI ID:
- 5217328
- Journal Information:
- Limnol. Oceanogr.; (United States), Vol. 30:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PHOSPHORUS
EXCRETION
UPTAKE
RETENTION FUNCTIONS
MATHEMATICAL MODELS
BIOGEOCHEMISTRY
COMPARTMENTS
DAPHNIA
PHYTOPLANKTON
ZOOPLANKTON
ANIMALS
AQUATIC ORGANISMS
ARTHROPODS
BRANCHIOPODS
CHEMISTRY
CLEARANCE
CRUSTACEANS
ELEMENTS
FUNCTIONS
GEOCHEMISTRY
INVERTEBRATES
NONMETALS
PLANKTON
560302* - Chemicals Metabolism & Toxicology- Microorganisms- (-1987)