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Melissa Lutz - Chesapeake Research Consortium/Phytoplankton Lab

St. Joseph's University, Philadelphia, PA


The effect of different nitrogen substrates on growth rate and biomass of Chattonella subsalsa

In my experiment, I used different sources and amounts of nitrogen to test what the algae, Chattonella subsalsa, grew the most and fastest with. I chose to research this algae because it started recently to bloom in the Maryland and Delaware areas. It produces brevetoxin; which causes fish mortality and respiratory problems in humans. I tested three different sources of nitrogen: nitrate, ammonium and urea. The change in biomass per day was measured with a fluorometer. The growth rate was determined by graphing the change in biomass vs. the time in days. The data showed that 882uM and 200uM nitrate had the highest growth rates and the highest final biomass. The media without any nitrogen and 200uM urea grew at a much lesser rate and had a low final biomass. The media with 200uM ammonium did not grow it all, but further investigation showed that 50uM ammonium will grow. This suggested that the cells might have been poisoned by too much ammonium initially. The cell sizes measured and recorded during different growth rates and different substrates were not significant. The differences in pigments from the different substrates and whether any of the cells produced brevetoxin has yet to be determined from this experiment.

Funding provided by National Science Foundation-REU