PS 38-106 - Quantification of fecal indicator bacteria on the surface of sugar kelp Saccharina latissima in proximity to anthropogenic sources

Wednesday, August 9, 2017
Exhibit Hall, Oregon Convention Center
Mary Grace Hollandbeck1, Adam St. Gelais2, Gretchen Grebe3, Kristin Burkholder4 and Carrie J. Byron1, (1)Marine Science Department, University of New England, Biddeford, ME, (2)Center for Excellence in the Marine Sciences, University of New England, Biddeford, ME, (3)School of Marine Science, University of Maine, Orono, ME, (4)Biological Science, University of New England

Kelp is increasing in popularity as a seafood among U.S. consumers because of its high nutritional benefits and product versatility. As with any new industry, regulations and guidelines for best practices are being developed as the industry develops and grows. Typically, water quality can be a good indicator for seafood safety and can be tested for fecal indicator bacteria (FIB) Escherichia coli and Enterococci. While not directly harmful to humans, FIB can be correlated to the presence of other harmful bacteria. Saco Bay, Maine, receives effluent from six different wastewater treatment plants and therefore, is a likely place for FIB to occur increasing the chances of it coming in contact with kelp growing sites. Six buoys were placed throughout Saco Bay with mature kelp attached in summer 2016. Kelp tissue and water was collected biweekly. FIB from each sample was cultured using a selective agar, incubated for 24 hours and then counted. This experiment will be repeated in 2017 spring-summer. While it has not yet been determined if kelp grown in conditions like those found in Saco Bay is harmful if consumed, it is important to identify any connections between the water quality and the seafood harvested from it.


The results from the 2016 experiment showed that FIB is present and spatially variable. The mean number of colony forming units (CFU) of Enterococci on the kelp for each of the six growing sites were calculated. The two sites closer to the river had higher mean CFU’s of 15 CFU’s and 159 CFU’s than the two further from the river with 6 CFU’s and 103 CFU’s. This is consistent with a proposed hypothesis that kelp grown closer to the source of FIB will have more CFU’s but more data are needed before any conclusions can be made. Results from summer 2017 study will shed more light on the relationship between the amount of fecal indicator bacteria found in the water and the amount found on the kelp. Fluctuations in bacteria observed were also compared with different anthropogenic impacts or environmental fluctuations (i.e. warmer water temperatures, fouling) throughout the summer. This research can provide the preliminary data needed for agencies such as the Food and Drug Administration to develop policies regarding kelp farming and production processes.