Pfiesteria, water quality and fish kills
Name: ______
In this exercise, each group will be responsible for understanding two figures and become experts on those figure. Then, groups will break up and regroup so that experts from each group teach each other. By putting all the figures together, you will see how data from scientific studies are pieced together to form a larger conclusion than each study alone.
A short background on Pfiesteria
JoAnn Burkholder, an ecologist from North CarolinaStateUniversity, published a paper on the discovery of Pfiesteria piscicida injournal Nature in 1992. Pfiesteria piscicida was discovered by accident when colleague of Burkholdernoticed that the fish tilapia held in tanks suddenly died several days after being exposedto water collected in the Pamlico River, NC. The scientists observed that density of asmall dinoflagellate increased before fish death and declined rapidly in number unlesslive fish were introduced. The dinoflagellate produced resting cysts or non-toxicamoeboid forms in the absence of fish (Burkholder et al. 1992). When Burkholder and her colleagues looked for dinoflagellates during massive fish kills in local estuaries, Pfiesteria was abundant, but only when fish were dying.
Pfiesteria does make people sick as well. Researchers suffered serious neurological effects when they unknowingly inhaled the Pfiesteria toxin. The scientists were hospitalized and affected for months. Pfiesteria is the first reported dinoflagellate that produces aerosols that seriously harm human nervous systems. Symptoms include acute respiratory problems blurred vision, nausea, vomiting, extreme headaches, and severe memory dysfunction. According to Burkholder and Glasgow (2001) "For days to weeks following exposure, several laboratory personnel could recognize words individually but could not form sentences, perform simple arithmetic, or remember more than the last words of a sentence directed to them. The most seriously affected person in our laboratory, who is a highly intelligent researcher, managed only a 7-year-old's reading level for 3 months after exposure and required reading lessons at first to help regain reading ability … two others … could not remember their names or where they had lived.”
Please answer the following questions to turn in at the end of the exercise.
Does this species kill fish? In what form does it attack and/or kill fish? What evidence supports this?
What causes populations of Pfiesteria to increase? What evidence supports this?
Pfiesteria outbreaks are a relatively new phenomenon. What actions are occurring to cause these outbreaks? What evidence supports this?
Based on the evidence presented, what environmental regulations would you propose to protect human and fish health?
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