Bioassays To Determine Nutrient Limitations of Algal Biomass

Abstract

Nutrient limitation in algal biomass is extremely important for the longevity of aquatic ecosystems.  While algae is necessary for an ecosystem to strive, in excess, it can be extremely harmful to the organisms within the ecosystem, as well as, the ecosystem as a whole.  In this experiment we determined which nutrients limit algae growth.  The nutrients that we tested were nitrogen, phosphorous, and iron. To determine nutrient limitation, we performed a 6-day bioassay, measuring algal biomass each day, relative fluorescence unit (RFU). We collected water samples from two different water sources: Boomer Lake and a local neighborhood pond.  We hypothesized that the pond water would be relatively nitrogen limited because of its close proximity to a neighborhood and point source runoff, and we hypothesized that Boomer Lake would not be nutrient limited, based on the lack of algae growth and high turbidity levels that were seen on in the water.  We found that the local pond was N limited, while Boomer Lake samples seemed to not exhibit nutrient limitation at all.