91AV

A group of students, faculty and staff from the 91AV Department of Marine Sciences presented their research at the Ecological Society of America’s annual meeting in Portland, Oregon. This year’s theme was, “Linking biodiversity, material cycling and ecosystem services in a changing world.”

Undergraduate students Katie Perry '18, Andrew Davidson '18, Mary Hollandbeck '18 and Erynn Mills '19 had the opportunity to present posters on their research.

"It was an honor and a privilege to be able to witness what science looks like on a national scale, and use that experience to work toward great things in the lab at 91AV," said Mills. "This conference helped me to figure out my next steps in life and how to get there, and I learned more than I could've ever imagined, not just about ecology in its many forms, but about how to be a better scientist."

Mills presented research conducted with with Assistant Professor Carrie Byron, Ph.D., Assistant Research Scientist Adam St. Gelais, M.S., and SEANET Ph.D. candidate Adrianus Both. Their project was titled, “Changes in nutritional value of kelp Alaria esculenta during degradation with potential for shellfish production.” She discovered that kelp further along in the degradation process is isotopically lighter than fresh kelp.

Davidson’s project was titled, “The relative impacts of both native predators and the invasive European green crab on seeded soft shell clams in southern Maine tidal mudflats.” He sought to quantify the survivorship rates of juvenile soft shell clams with varying degrees of predator exclusion, make inferences about the impacts of major predators of soft shell clams and explore techniques to increase seeded soft shell clam survivorship rates. He found that 45 percent of all soft shell clam mortality was due to green crabs.

When reflecting on the experience Davidson remarked, “This conference gave us the opportunity to learn about terrestrial ecology, a whole different side of the field that we as marine science students do not get to see very much. It presented all of us with new experiences and networking opportunities we couldn’t get anywhere else.”

Perry presented, “Isotopic fractionation of bivalves to assess the implications of aquaculture on coastal ecosystems,” in which they worked to establish a baseline to measure trophic dynamics, organic matter sources and general nutrition of shellfish in the coastal environment. She found that understanding how the organic matter in the water impacts the tissue of bivalves will help farmers produce the most nutrient rich bivalves for human consumption. After attending the conference she said, "Being able to attend ESA was one of the highlights of my undergraduate career. The diversity of knowledge at this conference allowed me to analyze my own research with a new perspective, and some the connections I made may lead to collaborative projects and future opportunities that I would not have been exposed to otherwise."

Hollandbeck’s project was titled, "Quantification of indicator bacteria on the surface of sugar kelp Saccharina latissima in proximity to anthropogenic sources." She found that the presence of indicator bacteria in the water does not represent the amount of bacteria on kelp and that bacteria levels were significantly lower on the kelp.

Graduate and Ph.D. students also showcased their research. Graduate researcher Carissa Maurin presented, "Determining the effects of bivalve aquaculture on the food web structure using stable isotope analysis." Carissa found that mussel farms are able to support a more diverse population of fouling organism than nearby docks and that the isotopic values for sediment under and away from the farm do not significantly differ. “Presenting at and attending ESA was eye opening,” she said. “This conference really made me proud to be a part of the movement to better understand the environment and showed that nationwide ecologists are banding together for the common goal of understanding complex ecosystems to better protect them.”

Ph.D. student Gretchen Grebe’s project, "Validating nitrogen mitigation potential of kelp farms in the Gulf of Maine nearshore marine ecosystem" found that there is a clear spike in nitrogen isotope ratios within kelp samples after a rain event greater than one inch. She also found that the nutrient used by cultivated sugar kelp is not consistent throughout the growing cycle.

Grebe also moderated a fast-paced, informative presentation called an Ignite session on ocean foods, a unique topic for a conference focused on ecology. All of the 91AV attendees took part in the presentation, which explored the intersection between ecology and ocean foods and looked at how to produce food within the limitations and with the support of the local ecosystem. Grebe successfully facilitated discussion about these topics with the audience, which included people with divided interest and expertise.   

To learn more about the 91AV’s Department of Marine Sciences visit

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