Interactions of a Toxic Estuarine Dinoflagellate with Microbial Predators and Prey

Summary The toxic ambush-predator dinoflagellate, Pfiesteria piscicida (gen.et.sp.nov.) targets finfish and shellfish prey, and is a causative agent of major fish kills in representative estuaries of the southeastern United States.Live fish or their fresh tissues stimulate toxicity and gamete production and fusion, which usually occurs within a benthic or floating gelatinous mass.After fish death, remaining gametes revert to asexual, nontoxic zoospores that thrive in nutrient-enriched waters with flagellated algal prey.In the absence of fish, transformations among nontoxic flagellated, amoeboid and encysted stages in the dinoflagellate's complex life cycle are influenced by the availability of microbial prey (bacteria, algae, and microfauna including p1'otozoan ciliates and rotifers.Three potential microbial predators of P.piscicida were identified, although one was subject to attack especially by larger amoeboid stages.The ubiquitous occurrence of flagellated and amoeboid stages in the water column and sediments of warm temperate/subtropical waters, and their voracious phagotrophy on bacterial, algal and microfaunal prey, pOint to a major role of toxic ambush-predator dinoflagellates in the structure and function of estuarine microbial food webs.

[1]  E. Lessard.  The trophic role of heterotrophic dinoflagellates in diverse marine environments , 1991 .

[2]  A. Bursa.  The Annual Oceanographic Cycle at Igloolik in the Canadian Arctic: II. The Phytoplankton , 1961 .

[3]  H. Spero,et al.  PHAGOTROPHIC FEEDING AND ITS IMPORTANCE TO THE LIFE CYCLE OF THE HOLOZOIC DINOFLAGELLATE, GYMNODINIUM FUNGIFORME 1 , 1981 .

[4]  F. Tailor.  The biology of Dinoflagellates , 1987 .

[5]  J. C. Goldman,et al.  Dynamics of herbivorous grazing by the heterotrophic dinoflagellate oxyrrhis marina , 1989 .

[6]  Engel G. Vrieling,et al.  TOXIC PHYTOPLANKTON BLOOMS IN THE SEA , 1993 .

[7]  J. Larsen.  An ultrastructural study of Amphidinium poecilochroum (Dinophyceae), a phagotrophic dinoflagellate feeding on small species of cryptophytes , 1988 .

[8]  K. Steidinger,et al.  SEXUAL REPRODUCTION IN THE TOXIC DINOFLAGELLATE GONYAULAX MONILATA 1 , 1979 .

[9]  E. Bovee,et al.  Marine flora and fauna of the northeastern United States. Sarcodina : amoebae / , 1979 .

[10]  T. Reimchen,et al.  A Novel Association between an Endemic Stickleback and a Parasitic Dinoflagellate.3.Details of the Life Cycle , 1995 .

[11]  Alan J. Lewitus,et al.  Discovery of the “Phantom” dinoflagellate in Chesapeake Bay , 1995 .

[12]  J. Burkholder.  Phytoplankton and episodic suspended sediment loading: Phosphate partitioning and mechanisms for survival , 1992 .

[13]  E. Carpenter,et al.  Novel Phytoplankton Blooms , 1989, Coastal and Estuarine Studies.

[14]  C. Turley.  Protozoa and Their Role in Marine Processes , 1991, NATO ASI Series.

[15]  R. Zingmark.  ULTRASTRUCTURAL STUDIES ON TWO KINDS OF MESOCARYOTIC DINOFLAGELLATE NUCLEI , 1970 .

[16]  L. Pfiester,et al.  Parasitic, amoeboid dinoflagellates , 1979, Nature.

[17]  J. Burkholder,et al.  Epiphytic microalgae on natural substrata in a hardwater lake: seasonal dynamics of community structure, biomass and ATP content , 1989 .

[18]  R. Rhodes,et al.  INGESTION AND RETENTION OF CHROOMONAS SPP. (CRYPTOPHYCEAE) BY GYMNODINIUM ACIDOTUM (DINOPHYCEAE) 1 , 1991 .

[19]  John J. Lee,et al.  An illustrated guide to the protozoa , 1985 .

[20]  T. Reimchen,et al.  A NOVEL ASSOCIATION BETWEEN AN ENDEMIC STICKLEBACK AND A PARASITIC DINOFLAGELLATE. 2. MORPHOLOGY AND LIFE CYCLE 1 , 1990 .

[21]  P. J. Hansen.  Quantitative importance and trophic role of heterotrophic dinoflagellates in a coastal pelagial food web , 1991 .

[22]  M. Ucko,et al.  Relationship between the Unicellular Red Alga Porphyridium sp. and Its Predator, the Dinoflagellate Gymnodinium sp , 1989, Applied and environmental microbiology.

[23]  Edward J. Noga,et al.  New 'phantom' dinoflagellate is the causative agent of major estuarine fish kills , 1992, Nature.

[24]  D. Anderson,et al.  THECATE HETEROPHIC DINOFLAGELLATES: FEEDING BEHAVIOR AND MECHANISMS 1 , 1986 .

[25]  J. Burkholder,et al.  Response of two zooptankton grazers to an ichthyotoxic estuarine dinoflagellate , 1995 .

[26]  E. Schnepf,et al.  Nutritional strategies in dinoflagellates: A review with emphasis on cell biological aspects. , 1992, European journal of protistology.

[27]  Hans W. Paerl,et al.  Seasonal phytoplankton composition, productivity and biomass in the Neuse River estuary, North Carolina , 1991 .

[28]  J. Burkholder,et al.  A new ichthyotoxic dinoflagellate: cause of acute mortality in aquarium fishes , 1993, Veterinary Record.

[29]  E. Seeberg,et al.  Cloning and expression of a rat brain L-glutamate transporter , 1992, Nature.

[30]  R. E. Lee.  Saprophytic and phagocytic isolates of the colourless heterotrophic dinoflagellate Gyrodinium lebouriae Herdman , 1977, Journal of the Marine Biological Association of the United Kingdom.