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Abstract

A simple Lagrangian model of phytoplankton growth dynamics is presented using dynamically passive but interactive tracers. Three state variables are considered: phytoplankton biomass, herbivorous zooplankton biomass, and a limiting nutrient. The model is designed for the simulation of eutrophication in coastal waters and is forced by Steele's light function and by the Michaelis Menten uptake kinetics. An intensive parameter test and sensitivity analysis is presented with respect to the intensity of the plankton blooming, as well as to the Lotka-Volterra predator-prey kinetics. Different sensitivities are found: sensitivity in the amplitude of phytoplankton growth, in the timing of the bloom (i.e. sensitivity in phase) and sensitivity in the Lotka-Volterra predator-prey kinetics, or a combination of these three. The strongest sensitivity in the model occurs in the variation of underwater light. The results suggests that underwater light cannot play a fundamental role in the case of strong algal blooms due to the limiting effect on phytoplankton growth. Vertical profiles of phytoplankton show an extreme sensitivity to the variation of physical parameters, such as underwater light, temperature and eddy diffusivity. These results suggest that the sensitivity with respect to physical parameters is much stronger than to biological coefficients.

Additional information

Authors: DIPPNER J W, JRC Ispra (IT)
Bibliographic Reference: EUR 13371 EN (1991) 63 pp., MF, ECU 4, blow-up copy ECU 8.75
Availability: (2)
Record Number: 199111052 / Last updated on: 1994-12-02
Category: PUBLICATION
Original language: en
Available languages: en