2005 Progress Report: Linking Population and Physiological Diversity in a Toxin-producing Dinoflagellate

EPA Grant Number: R830413
Title: Linking Population and Physiological Diversity in a Toxin-producing Dinoflagellate
Investigators: Campbell, Lisa , Gold, John R.
Institution: Texas A & M University
EPA Project Officer: Hiscock, Michael
Project Period: September 1, 2002 through August 31, 2005 (Extended to February 28, 2007)
Project Period Covered by this Report: September 1, 2004 through August 31, 2005
Project Amount: $464,880
RFA: Ecology and Oceanography of Harmful Algal Blooms (2002) RFA Text |  Recipients Lists
Research Category: Water Quality , Ecosystems , Water , Aquatic Ecosystems


The primary objective of this project was to develop molecular tools for examining genetic diversity within and among blooms of Karenia brevis, atoxic dinoflagellate responsible for harmful algal blooms (HABs) in the Gulf of Mexico. During the initial 2 years of the project, hypervariable genetic markers known as microsatellites were developed in order to ultimately characterize individual blooms and test whether spatial and/or temporal genetic differences existed between or among blooms. The long-term objective is to utilize the genetic information to provide a better understanding (and predictability) of the dynamics of this HAB species. Objectives of the project include:

  1. Optimization of a suite of hypervariable, nuclear-encoded DNA markers (microsatellites) to characterize genetic diversity among strains of the toxic dinoflagellate K. brevis.

  2. Isolation and establishment of clonal cultures of K. brevis sampled during the onset, bloom, and decline of a toxic algal bloom event.

  3. Utilization of the highly polymorphic molecular markers to elucidate population structure.

Progress Summary:

Results obtained to date in the project include isolation and characterization of hypervariable genetic markers that are useful for cataloguing clones of K. brevis using both live material and Lugol’s preserved material. The capability to distinguish genetically among strains of K. brevis (i.e., genotype) is now possible. With these data, a genetic database for K. brevis on both spatial and temporal scales has been established for the Gulf of Mexico. In addition, one of the genetic markers developed and characterized appears to distinguish unequivocally two species of Karenia (K. brevis and K. mikimotoi) and has the potential to serve as a taxonomic tool to distinguish all five described species of Karenia. The capability to positively identify individual species of Karenia will be highly useful, as these species are very difficult to distinguish following preservation.

A new assay to determine hemolytic activity of toxins from Karenia species has been published (Neely and Campbell, 2006 ). Results with existing cultures demonstrate that toxicity due to hemolytic activity was greater in K. mikimotoi than in K. brevis. We hypothesize that this finding of variable toxicity among strains of these two species of Karenia may explain part of the variability in toxicity and fish kills among HAB events. Characterization of the hemolytic toxin in K. mikimotoi is currently underway.

Future Activities:

Efforts in the final year of the project will focus on the following:

  1. Isolate and establish clonal cultures of K. brevis sampled during the onset, bloom, and decline of a toxic algal bloom event, and assess genetic and physiological variability within a bloom population.

  2. Elucidate population structure for the October 2005 bloom in Texas utilizing the 10 microsatellite loci identified.

Results will be presented at the 12th International Conference on Harmful Algae to be held in Copenhagen in 2006.

Journal Articles on this Report : 1 Displayed | Download in RIS Format

Other project views: All 21 publications 6 publications in selected types All 5 journal articles
Type Citation Project Document Sources
Journal Article Neely T, Campbell L. A modified assay to determine hemolytic toxin variability among Karenia clones isolated from the Gulf of Mexico. Harmful Algae 2006;5(5):592-598. R830413 (2005)
R830413 (Final)
  • Full-text: Science Direct
  • Abstract: Science Direct
  • Other: Science Direct
  • Supplemental Keywords:

    RFA, Scientific Discipline, Water, Ecosystem Protection/Environmental Exposure & Risk, Oceanography, algal blooms, Biochemistry, Ecological Risk Assessment, Ecology and Ecosystems, marine ecosystem, toxin monitoring programs, marine biotoxins, bloom dynamics, brevetoxins, phytoplankton, gene sequences, dinoflagellate, algal bloom detection, dinoflagellate blooms, K. brevis, Karenia brevis

    Relevant Websites:

    phytoplankton ecology, molecular genetics, marine, estuarine, coastal, population diversity, ecology and ecosystems, genetics, molecular biology/genetics, oceanography, algal blooms, Karenia brevis, algal bloom detection, bloom dynamics, brevetoxins, dinoflagellate, dinoflagellate blooms, gene sequences, marine biotoxins, marine ecosystem, marine toxins, phytoplankton.,

    Progress and Final Reports:

    Original Abstract
  • 2003 Progress Report
  • 2004 Progress Report
  • 2006
  • Final Report