The Toxic Dinoflagellate, Pfiesteria piscicida, as a Potential Biosensor of Estuarine Stress

EPA Grant Number: R825551
Title: The Toxic Dinoflagellate, Pfiesteria piscicida, as a Potential Biosensor of Estuarine Stress
Investigators: Burkholder, Joann M. , Rublee, Parke , Shumway, Sandra E.
Institution: North Carolina State University , Long Island University - Southampton College , University of North Carolina at Greensboro
Current Institution: North Carolina State University , Long Island University - Southampton College , University of North Carolina at Greensboro
EPA Project Officer: Hiscock, Michael
Project Period: May 19, 1997 through May 18, 2000 (Extended to May 18, 2001)
Project Amount: $500,000
RFA: Harmful Algal Blooms (1997) RFA Text |  Recipients Lists
Research Category: Aquatic Ecosystems , Water Quality , Water , Ecosystems


A recent cosmopolitan rise in the frequency and spatial extent of toxic phytoplankton blooms suggests that these noxious species can significantly reduce estuarine and marine fishery resources. In the early 1990s we discovered a new genus of "ambush-predator" dinoflagellate, Pfiesteria, with known species having a complex life cycle of at least 22 stages including persistent ichthyotoxic amoebae and flagellates. Pfiesteria-like dinoflagellates are common in previously examined mid-Atlantic and east Gulf Coast estuaries, and likely are widespread throughout temperate and subtropical eutrophic waters. The apparent ubiquitous occurrence and abundance of these stages in estuarine waters and sediments, their voracious phagotrophy on photosynthetic/heterotrophic microbial prey, and their lethality to finfish and shellfish point to a major role of Pfiesteria species in the trophic balance and productivity of estuarine food webs.

In the proposed research, we plan to (i) examine controlling influences of both inorganic and organic N and P on growth of Pfiesteria piscicida zoospores (toxic and nontoxic), when given food resources as dissolved or particulate (algal) carbon; (ii) improve detection of flagellated lated, amoeboid, and encysted stages of P. piscicida by developing and testing species-speci- fic molecular probes; and (iii) assess Pfiesteria's acute and sublethal/chronic impacts on life stages of commercially / ecologically valuable shellfish species.


Nutritional (N,P) controls on Pfiesteria zoospore abundance and stage transformations will be examined through a series of experiments under controlled laboratory conditions, in which nutrient gradients will be imposed with vs. without supplementary carbon sources (dissolved organic carbon as acetate; particulate organic carbon as algal prey) under controlled laboratory conditions. We plan to expand upon research progress to date in developing fluorescentlabeled molecular probes to enable rapid, routine detection of Pfiesteria's major life cycle stages in fish kill and ulcerative fish epizootic sites. And, in a second series of laboratory experiments, we will compare acute and sublethal/chronic impacts of P. piscicida on survival and selected metabolic processes in representative shellfish species.

Expected Results:

This research will enhance our ability to detect Pfiesteria-like dinoflagellates in early diagnosis of aquaculture facilities contamination, as well as in the wild during fish kills and epi- zootics. It will also strengthen our understanding about influences of anthropogenic nutrient loading on Pfiesteria-like dinoflagellates, and their ecological, physiological, and cytotoxicological effects on shellfish. The insights from our data will improve strategies for evaluating chronic sublethal effects of shellfish exposure to these toxic dinoflagellates, and will also evaluation of their potential utility as biosensors of estuarine stress from cultural eutrophication.

Publications and Presentations:

Publications have been submitted on this project: View all 19 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 16 journal articles for this project

Supplemental Keywords:

estuaries, nutrients., RFA, Scientific Discipline, Water, Waste, Ecosystem Protection/Environmental Exposure & Risk, Hydrology, Nutrients, Ecosystem/Assessment/Indicators, Ecosystem Protection, exploratory research environmental biology, Chemical Mixtures - Environmental Exposure & Risk, Contaminated Sediments, Environmental Microbiology, Ecological Effects - Environmental Exposure & Risk, algal blooms, Ecological Effects - Human Health, Ecological Risk Assessment, Ecology and Ecosystems, Ecological Indicators, aquatic ecosystem, nutrient supply, nutrient transport, pfiesteria piscicida, ecological exposure, dinoflagellates, estuaries, food web, watershed management, fish lesions, harmful algal blooms, contaminated sediment, estuarine stress, nutrient kinetics, phytoplankton, heterotrophic microbial prey, algal growth, pfiesteria, phytoplankton dynamics, estuarine ecosystems, nutrient cycling, phytoplankton blooms, dinoflagellate, water quality, biosensor, estuarine food web

Progress and Final Reports:

  • 1997 Progress Report
  • 1998 Progress Report
  • 1999 Progress Report
  • Final Report