http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Managing phytoplankton community composition
Noxious bloom events are becoming more prevalent with
increasing anthropogenic activities. To lessen ecological
damage, there is a need to develop phytoplankton management
programs aimed at enhancing growth of beneficial algae. The
success of such management schemes will be dependent on the
predictability of phytoplankton succession within the target
system to a controlled perturbation. Freshwater lakes appear
to exhibit a degree of predictability as described by the
conceptual model of the Phytoplankton Ecology Group (PEG-
model) and Equilibrium Resource Competition theory (ERC-
theory). Using mathematical models and field data collected
from the Nueces River estuary, Texas, I investigated whether
the PEG-model and ERCtheory could be applied to a marine
system. I also investigated approaches to managing
phytoplankton community composition through nutrient loading.
Initial growth and accumulation of biomass of edible
phytoplankton forms after a favorable nutrient perturbation,
a predominant feature of the PEG-model, was consistently
observed in the field data and mathematical models.
Dominance of phytoplankton species with optimal nitrogen to
phosphorus ratios similar to ambient nitrogen to phosphorus
ratios, the crux of ERC-theory, was not consistently observed
in the field data or mathematical models. Rather the ability
of a phytoplankton species to successfully compete against
other algae was a function of its physiological growth and
morphological characteristics. In the Nueces River estuary,
succession within the phytoplankton community showed a degree
of predictability to nutrient perturbations. Therefore,
management of the phytoplankton community composition may be
possible. The PEG-model appears to be a useful guide for a
phytoplankton management scheme, while the utility of ERC-
theory may be limited. The mathematical models indicated
that supplying the nutrients to an estuary in a pulsing
fashion may allow greater growth of beneficial algae and
subsequent growth of copepods. Further model refinement and
characterization of the target system (in this case the
Nueces River estuary) are necessary, however, before models
of this nature can be used as a guide to phytoplankton
Issued also on microfiche from University Microfilms Inc.
Includes bibliographical references: pages 196-214.