Sarah Jardeleza - Protistan Ecology Lab

St. Mary's College, St. Mary's City, MD


A Journey Into the Amazing World of Dinoflagellates

From my previous experiences, microscopy had always been a useful tool, but with greater instruction and practice it has become an art form. I like to think of it as photography, but of very minute specimens. The minute organisms that I have had the pleasure of working with in my internship at SERC are dinoflagellates. Specifically, I have been immersed in the relationship between the parasitic dinoflagellate Amoebophrya sp. and one of its hosts Akashiwo sanguinea.

The person that threw me headfirst into this highly unexplored territory of protozoan ecology is Wayne Coats. Although formidable at first with his short stature, he is an excellent P.I. because he encompasses the roles of slave driver, counselor, technician, and most of all he is a teacher. I was given several research papers that were published from work performed in his lab and I was allowed to choose any topic as the subject of my summer research project. I chose to undergo the task of taking a closer look at the morphology of several of the life stages of the Amoebophrya sp., utilizing both light and scanning electron microscopy.

Historically, it was understood that Amoebophrya sp. was a parasitic dinoflagellate that affected several species of dinoflagellates that cause harmful algal blooms (HABs). Because of the lack of host specificity that Amoebophrya sp. exhibited, the use of it as a biological control for HAB forming dinoflagellates was not considered a viable option. However, recent work has revealed new information on the parasite.

The protozoan ecology lab at SERC is the only lab to culture this Amoebophrya sp., and its researchers uncovered that the infection of the host species by the parasite caused the hosts to decrease in number. The lab and collaborating labs have performed several experiments that propose Amoebophrya sp. might be a species complex, rather than a single species. Infection trials, field observations, and several aspects of genetic analysis support this. This leads to a great deal of work that still needs to be done.

My niche is to unlock the variation in morphology of Amoebophrya spp. I have done most of my work with the Amoebophrya sp. that infects A. sanguinea, as was mentioned previously. I have photographed the ephemeral stages of the zoospores and vermiforms of this species. I will continue my work by repeating the process for the parasites that infect two other host species, Karlodinium micrum and Gymnodinium instriatum, and compare the parasites’ morphologies in those two life stages. I will be continuing this work through the summer of 2003.

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