| Sabellaria vulgaris (S. vulgaris ) is a tube-building annelid polychaete found in dense aggregations throughout Delaware Bay. The worms build reefs on geologic hard bottom such as gravel, cobbles, or shells by cementing sand grains together to form masses of tubes. These structures provide habitat for a variety of organisms, which increases local species diversity.; Although intertidal communities of S. vulgaris in Delaware Bay have been studied extensively, aggregation size, worm abundance, and specific sediment requirements are not well constrained for subtidal colonies. In order to better understand this habitat, an intensive mapping and sampling project was undertaken. During the summer of 2004, a suspected location of subtidal Sabellaria vulgaris 3.5 kilometers offshore of Slaughter Beach was mapped and sampled. The site had previously been identified as an area of high S. vulgaris abundance during a pilot study by Madsen (2004).; Roughness (E1) and hardness (E2) values for the site were first mapped with the RoxAnn(TM) seabed classification system. The site was then grab sampled to determine worm abundance, to determine the preferred sediment type for subtidal S. vulgaris, and to determine if the system is capable of differentiating between bottom sediment and worm colony characteristics. In total, 78 samples were collected; of these, 72 samples were analyzed using standard dry sieving methods and the total number of S. vulgaris in each grab sample was tallied. Results were then statistically analyzed to understand the correlations between worm abundance, E1 and E2 values, and sediment size. (Abstract shortened by UMI.)... |
