| The eutrophication of coastal waters from land-derived nutrients affects all biological aspects of the estuarine ecosystem. Changes to the benthic community can be pronounced. Not only do benthic species respond to nutrient-induced phytoplankton blooms, but these animals may have a subsequent impact on the system.;A sixteen-month study was conducted in 13 m;A two to five-fold increase in abundance and biomass was observed in enriched over control mesocosms. A shift in species composition included the rapid response of facultative suspension-feeding spionid polychaetes, Polydora ligni and Streblospio benedicti, and amphipods, Ampelisca abdita and Corophium sp., to phytoplankton increases. Benthic abundance was greater in one of the enhanced silicon mesocosms compared to the other nutrient systems, although differences were not statistically significant by the second summer. Zooplankton initially responded to phytoplankton blooms but adult benthic suspension feeders dominated the grazer biomass within three months of nutrient additions.;Benthic grazers could remove up to 75% of water column phytoplankton per day. Rates were higher in nutrient-enriched systems where animal biomass was greater than in control enclosures. Phytoplankton ;The results of this study are most applicable to shallow, well-mixed coastal areas. As water column depths decrease and/or food is more accessible to the benthos, benthic-pelagic coupling increases in importance. |
