Record Details
Mathematical model of a phytoplankton community in a nitrate limited environment
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Mathematical model of a phytoplankton community in a nitrate limited environment |
| Names |
Grenney, William J.
(creator) Bella, David A. (advisor) |
| Date Issued | 1972-01-03 (iso8601) |
| Note | Graduation date: 1972 |
| Abstract | Mathematical modeling of phytoplankton populations based on laboratory observations provides increased understanding of the interaction among the environmental and biological mechanisms. influencing growth dynamics. Such fundamental understanding is necessary to estimate the impact of man-made perturbations on natural population. A three-compartment mathematical model was developed to represent a phytoplankton population having the capability to store nitrogen in a nitrate limited environment. Parameters were estimated by fitting the model to data from two chemostat experiments reported in the literature. The model was solved by numerical techniques on a digital computer. The model was used to simulate growth dynamics observed in chemostat and batch experiments. The model demonstrated the changes which may occur in the nitrogenous constituents of a phytoplankton population with time and environmental conditions. The model also demonstrates three phenomena which have been observed in field and laboratory experiments but which are not represented by the customary Monod model: 1) uptake rates may significantly exceed net growth rates, 2) high growth rates may be encountered at very low environmental nitrate concentrations, and 3) the ratio of internal nitrogen to population size may change significantly during a study period. It is suggested that the amount of nitrogen storage may be used as an indicator of the physiological state of the population. Parameters for the one-compartment Monod model were estimated by customary methods from data generated by the three-compartment model. It was shown that difficulties encountered in estimating the yield coefficient and the decay coefficient may be attributed to the intracellular storage phenomenon. It was also demonstrated that the one-compartment Monod model was inadequate to accurately represent population growth in chemostat experiments when intracellular storage is a significant factor. The model was applied to a completely mixed system to demonstrate the succession of blooms and coexistence of species in phytoplankton communities as influenced by temporal variations in the environmental conditions. The model was expanded to include the one-dimensional vertical distribution of the phytoplankton in the water column. The influences of light, temperature, and water turbulence on the growth and distribution of the population were included in the model. |
| Genre | Thesis/Dissertation |
| Topic | Phytoplankton |
| Identifier | http://hdl.handle.net/1957/45205 |
