TOWARDS UNDERSTANDING RELATIONSHIPS AMONG ECOSYSTEM COMPONENTS: A SUBMERGED HABITAT STUDY IN CAPE COD NATIONAL SEASHORE

Human population growth has resulted in increased nutrient enrichment through land clearing, production and use of fertilizers, and fossil fuel combustion. Coastal areas are particularly threatened due to their density of population. Approximately 40% of Cape Cod National Seashore (CCNS) is submerged coastal habitat, making water quality monitoring and a baseline inventory of its marine habitats critical. Benthic habitat mapping can be used to identify changes when they occur, allowing for better management of our resources. The habitats at CCNS range from sand flats to sea grass beds, in areas of both high and low flow. These differing conditions allow for a better understanding of the drivers influencing benthic composition.

During the summer of 2014, benthic grabs, sediment samples, and sediment cores were collected throughout 48 stations in the Pleasant Bay system within and adjacent to CCNS. In addition, mapping surveys and vessel-based acoustic data were collected to map the seafloor. Through the CCNS NPS Estuarine Nutrient Enrichment (ENE) monitoring, long-term water quality data has been collected in Pleasant Bay. Water quality and sediment composition were important factors in determining benthic species composition. Spatial differences were observed in both water quality measurements and invertebrate assemblages when separated by bay area, and there was a trend of increased nutrient enrichment moving away from the inlet. Understanding these drivers can help explain the impacts of nutrient enrichment on coastal habitats and benthic invertebrate communities. These organisms, although low on the food web, are the foundation supporting higher trophic levels. Analyzing the physical and biological data alongside water quality parameters provides a detailed baseline understanding of the ecosystem, and, in the event of future changes to our coastline, helps us to predict its effect on benthic community structure.