Other people have reported burning skin and respiratory irritation, followed by problems with concentration. Funding for the research was provided by grants from the National Oceanic and Atmospheric Administration's Sea Grant College Program, the National Sea Grant Marine Biotechnology Program and the National Science Foundation. Support was also provided by the Duke University department of psychiatry and Integrated Toxicology Program, the N.C. State department of botany, the N.C. Agricultural Research Service, the U.S. Environmental Protection Agency and the National Institute of Environmental Health Sciences. Marine biologist Burkholder, a co-investigator of the current study, discovered Pfiesteria in 1988. After intense study, she and her co-workers at North Carolina State determined the organism is a type of dinoflagellate, which forms plankton, tiny marine organisms that provide food for many small marine animals.
Most dinoflagellates are harmless.
However, some dinoflagellates are toxic, producing powerful nerve poisons to deter fish from eating them. Pfiesteria, in contrast, uses its toxins to attack and eat fish flesh. For the current study, Burkholder provided water samples from her laboratory that contained active, fish-killing Pfiesteria toxin. The researchers conducted the experiments in two stages, each designed to measure the effects of the toxin on the rats' ability to learn and remember a task. First, scientists injected 26 rats with aquarium water containing Pfiesteria toxin and tested their ability to remember the maze in comparison to 26 rats injected with aquarium water without the toxin.