The Susannah Kent skimmed the water as we approached the pink buoy near Hay Island. Drew pulled on a line attached to the buoy, and retrieved his homemade settlement plates, which looked vaguely like satellites. “Nothing yet,” he said after inspecting the panels for fouling communities, the organisms that are the subject of his new project. After photographing the device, he dropped it back into the ocean, and it disappeared as it sank slowly into the gray-green murk.
Drew is researching the effects of currents on the diversity of organisms that settle on hard surfaces. These “fouling communities” begin their lives as plankton that settle on rocks, docks, and other surfaces. They include bryozoans, Drew’s original study subject, as well as sea squirts, barnacles, and sponges. Drew’s original research project focused entirely on invasive bryozoans, but they haven’t appeared on Kent Island yet, and he had to adapt his project to the reality of current conditions on the Island. Drew will study the effects of currents on invasive bryozoans if they show up later in the summer, but otherwise his focus will be on native biodiversity, which affords him greater flexibility. The students working on new research projects don’t have the luxury of pilot research to test out whether their project idea is feasible, and trial-and-error in the field is the only way to find out.
To study biodiversity, Drew has built settlement plates and put them in areas of different current strengths around the Island. Anchoring the plates required lots of creative engineering. Drew put one plate in a large tide pool on the South side of the Island, a high-action area where two currents meet. He jumped into the pool in his (extremely thick) wetsuit and anchored the plates to an old aquaculture cage, one of the many wrecks that end up in the intertidal zone of the Island. He attached another plate to the pole of a herring weir, which had flourished around the Three Islands before they became bird sanctuaries. The fouling communities won’t appear on the plates for a few weeks after they are submerged, especially because organisms grow so slowly in the cold Canadian water, so Drew’s negative findings today weren’t a surprise. His initial hypothesis is that there will be greater biodiversity on the plates in calmer areas, such as West Beach, which is protected from waves by surrounding Islands. He predicts that the tides that rip through the high current areas will prevent fouling communities from settling there. Hopefully the communities will begin to grow on his plates soon, but, as Damon frequently reminds discouraged students, “either way, the results will be interesting.”
Drew’s project may have implications for aquaculture, which is a major industry on Grand Manan. Studies have shown that fouling communities that grow on the outside of fish cages, made of the same material to Drew’s settlement plates, may weigh them down and impede productivity.There are many possible applications of Drew’s research, but for now he is waiting to see what appears. If he returns in October to check on his plates, he may see the transformation of the fouling community from pioneers such as sea squirts and bryozoans, which quickly coat surfaces “like snot” in Drew’s words, to barnacles, which take longer to grow.
Greene, Jennifer K., and Raymond E. Grizzle. “Successional development of fouling communities on open ocean aquaculture fish cages in the western Gulf of Maine, USA.” Aquaculture 262.2 (2007): 289-301.