USING SEDIMENTOLOGY, FORAMINIFERA, AND SEABED MORPHOLOGY TO ASSESS THE ENVIRONMENT OF SUGARLOAF ISLAND, NC BEFORE AND AFTER A COASTAL SHORELINE STABILIZATION PROJECT

Sugarloaf Island is a spoil island within Bogue Sound, off the coast of Morehead City, NC, whose shoreline is eroding, making it the focus of a shoreline stabilization project consisting of wave attenuation devices (WADs), subaquatic vegetation (SAV, i.e., coastal seagrass), oyster reefs, and a rock revetment. Foraminifera species distribution, sediment characteristics, and seabed morphology are being mapped to provide information on sediment sources and transport, erosion patterns, and storm impacts. In total, 40 samples were collected offshore and on the beaches before the emplacement of the stabilization structures. In addition, 22 of the onshore and adjacent offshore sample locations were resampled after the finalization of the structures. Side-scan sonar data (450 kHz) were acquired to produce a mosaic that is being analyzed for seabed morphology and acoustic backscatter data to be correlated with grain size characteristics. Sediment samples analyzed thus far are generally moderately to well-sorted and consist of very fine to fine, slightly gravelly sand. Sedimentological trends from pre-stabilization beach samples suggest a sediment source from island erosion with a dominant west-to-east transport direction. Post-stabilization sedimentological analyses are pending. Living (stained) foraminifera are being identified alongside the dead modern and fossilized specimens. The foraminifera identified thus far are mainly modern benthics with several percent fossil foraminifera on a spit west of the island. The most abundant foraminifera species are Elphidium excavatum and Ammonia parkinsoniana.