An examination of pelagic Sargassum community primary productivity and nutrient cycling in the face of Gulf Stream based energy

Pelagic Sargassum macroalgae entrained in the Gulf Stream serves as habitat for commercially and recreationally important fish and protected sea turtles, among other organisms. It also plays an important role in the sourcing of carbon, nitrogen, and phosphorus to the otherwise deficient oligotrophic pelagic waters of the Atlantic Ocean. Sargassum is seasonally concentrated along the western wall of the Gulf Stream off the coast of North Carolina. The Gulf Stream is a fast and constant western boundary current that consistently comes in close proximity to land off the coast of Cape Hatteras, North Carolina. This area is thus an area of interest for harnessing Gulf Stream energy. Gulf Stream turbines will likely be far removed from the surface of the water, and thus, the buoyant Sargassum that floats there. Nonetheless, the functional roles of Sargassum and its epibionts, including primary production and nutrient cycling, may be either negatively or positively influenced by Gulf Stream turbine wake. Our research, conducted in mesocosms, examined how an increase in turbulence affected the primary production and nitrogen fixation by Sargassum macroalgae and its associated epibiotic communities.