Assessing Algae Survivorship following Snail Grazing

A study by Porter (1976) showcases planktonic chlorophyta within the family of Sphaerocystis to be the best at surviving digestion by grazers due to presence of a complicated polysaccharide sheath found on the cells. This sparked interest in studying the survivorship of different algal groups after undergoing digestion by a two species of grazing snails (Physa sp. and Lymnaea sp.). Fecal samples were carefully examined to identify the cells and their abundance in order to compare a digested sample of algae to one uneaten. We hypothesized that cyanobacteria will have the highest survivorship amongst the algae groups due to the presence of a mucous membrane. Our results show a shift in the total cell distribution following digestion. Physa sp. had ~79% of the overall bacillariophyceae cells from the uneaten algae sample in the fecal sample, with an increase of ~580% for cyanobacterial cells and an increase of ~88% for chlorophyta. Bacillariophyta for Lymnaea sp. decreased to ~68% compared to the original uneaten algae sample along with an increase of ~492% for cyanobacteria and an increase of ~150% for chlorophyta. We learned that cyanobacteria had the highest survivorship. I grant the Regents of the University of Michigan the non-exclusive right to retain, reproduce, and distribute my paper, titled in electronic formats and at no cost throughout the world. The University of Michigan may make and keep more than one copy of the Paper for purposes of security, backup, preservation and access, and may migrate the Paper to any medium or format for the purpose of preservation and access in the future. Signed,