Harmful Algal Blooms: Environmental Consequences of Variance in Genetics and Toxicity

EPA Grant Number: U916245
Title: Harmful Algal Blooms: Environmental Consequences of Variance in Genetics and Toxicity
Investigators: Wilson, Alan E.
Institution: Duke University
EPA Project Officer: Graham, Karen
Project Period: January 1, 2003 through January 1, 2006
Project Amount: $100,264
RFA: STAR Graduate Fellowships (2003) Recipients Lists
Research Category: Academic Fellowships , Aquatic Ecosystems , Fellowship - Aquatic Ecology and Ecosystems


The objective of this research proposal addresses well-studied process (i.e., herbivory) affecting phytoplankton community succession, with an emphasis on understanding the ecological and evolutionary consequences of herbivory, and how these may promote noxious algal blooms. More specifically, my research objectives will evaluate the potential for grazers to shift phytoplankton communities composed of a diverse assemblage of toxic and nontoxic phytoplankton species towards a community dominated by near monoculture of an unpalatable algal species (i.e., harmful algal bloom). However, my research focuses not only on among-species differences in susceptibility to grazing, but also will assess these differences among-clones within a species (i.e., genetically distinct sympatric conspecific isolates). This focus provides a contrast to previous investigations describing grazer preferences among different species of algae or preferences among several strains of the same species of algae isolated from different lakes at different times. It has been suggested that ecologically important grazers may prefer particular strains of an algal species over other sympatric, conspecific clones, and that these preferences may have cascading effects on higher trophic levels. However, experiments to elucidate the specific response of sympatric, conspecific clones to dominant grazers—and the reciprocal effects of different clones of phytoplankton on sympatric conspecific grazer clones—have not been performed, either in the laboratory or in situ.


Briefly, after identifying algal blooms in nature, cyanobacterial isolates and pelagic grazers will be collected from several sites within the algal bloom. Growth rate estimates will be calculated for each algal isolate, and these estimates then will be used to determine which isolates (fast growers versus slow growers) to include in feeding assays with sympatric and allopatric grazers. Effects on grazers and grazed will be estimated with typical morphological or physiological measurements. If variation exists for palatability of different cyanobacterial isolates, future work will try to elucidate the morphological or chemical mechanisms driving this variation. Field mesocosm experiments may be implemented to determine if results seen in the laboratory can be extrapolated to field conditions.

Data produced will contribute to our understanding of important ecological issues, such as the selective forces driving succession in phytoplankton communities, the role of phenotypic and physiological variation within phytoplankton populations in affecting community structure and function, and more generally, the ecological and evolutionary consequences of plant-herbivore interactions and how these affect trophic webs and the energy and nutrient flows within aquatic systems. In addition, the proposed research will have broader societal benefits by improving our understanding of a potential mechanism for the promotion of harmful algal blooms.

Supplemental Keywords:

fellowship, algal bloom, phytoplankton, herbivory, algal isolate, phenotypic and physiological variation, aquatic systems., RFA, Scientific Discipline, Water, Ecosystem Protection/Environmental Exposure & Risk, Aquatic Ecosystems & Estuarine Research, Aquatic Ecosystem, algal blooms, Ecological Risk Assessment, Ecology and Ecosystems, toxicity studies, bloom dynamics, toxic cyanobacteria, phytoplankton, aquatic ecosystems, genetic adaptation, marine phytoplankton, algal toxins

Relevant Websites:

2004 STAR Graduate Fellowship Conference Poster (PDF, 1p., 230KB, about PDF)