Spring 2017

Document Type

Poster Session


Biological Sciences


Chris Maher


Stormwater runoff and sewage seepage are sources of chemicals and pathogens that lower immunity of marine organisms such as the common periwinkle (Littorina littorea), which can increase susceptibility to parasites. Periwinkles infected with parasites are less bold and show altered movements. The purpose of my study was to 1) identify pathogens in water that can affect marine organisms, 2) determine if water quality affects boldness in periwinkles, and 3) determine if water quality affects movement and substrate choice in periwinkles. I predicted that water samples vary in levels of fecal indicator bacteria because samples were collected from areas at high risk of sewage seepage and stormwater runoff. Based on previous work, I also predicted that periwinkles exposed to higher contamination levels are less bold and move shorter distances. I collected periwinkles from the same location and assigned them to 1 of 3 water quality groups. I tested water samples for E. coli and other bacteria, I measured boldness in periwinkles as latency to re-emerge from their shells, and I recorded rates of movement and choice of substrates. E. coli was present in 1 of the 2 expected contaminated samples. Periwinkles housed in water from the high sewage seepage area were more bold than those in the control tank and spent more time on substrate. Distance traveled did not differ among water treatments. In conclusion, bacteria may affect the behavior of marine organisms. My data add to research comparing water quality and behavior of marine organisms.

Start Date

4-28-2017 9:00 AM



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