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PECONIC ESTUARY PROGRAM TIDAL CREEK STUDY
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Description:
EEA evaluated ten tidal creeks throughout the Peconic Estuary representing a wide range of watershed variables. Primary focus was directed towards the collection and analysis of the macrobenthic invertebrate communities of these ten tidal creeks. Analysis of the macrobenthic communities indicated the relative health of the creeks. Land use, water quality, bathymetry, hydrodynamics, physical chemistry, grain size, and wildlife was also evaluated, with the intention of obtaining an overall analysis of the ten creeks, and also to assess whether the land use surrounding each creek could be correlated to the water quality and macrobenthic community structures found in each system. The ultimate goal of this study was to understand the relationship between nutrient inputs, primary productivity, and the biotic communities within the creeks and land use of immediately adjacent shorelines by comparing collected data for each selected creek. Nutrient loading appeared to be the primary impact to the creeks. Of the ten creeks, four clearly had a benthic community structure which was more representative of a nutrient rich environment closely resembling communities found in water bodies such as Jamaica Bay, New York and the New York Harbor: Meetinghouse, West Neck, Ligonee, and Alewife. This is not totally unexpected, as the drainages these creeks are associated with have been previously identified by the Suffolk County Department of Health Service as areas with above normal levels of nitrogen. In all cases, the source of nitrogen has been identified as a municipal sewage treatment plant, or in the case of Meetinghouse Creek, an active duck farm. In most cases, the diversity in each creek was low, and the density of a single species extremely high. The amphipod Ampelisca abdita was the dominant identified species. In some cases, Ampelisca abundances exceeded 30,000/mz. These species and densities indicate a stressed environment, which is most likely the result of nutrient loading. The organisms present are not necessarily detrimental to the environment, as they provide an excellent food source for many juvenile fin.fish species. The remaining six creeks (Fresh Pond, Northwest Creek, West Creek, Goose Creek, Bass Creek, and Little Bay) all appear to support well established benthic communities. This determination is based on the presence of a diverse benthic community that is not dominated by large numbers of pioneering organisms, such as the ampeliscids, spionid worms, and oligochaetes. In general, as one would expect, these six creeks are the more underdeveloped systems, with predominantly open space (i.e., intertidal marsh) surrounding them. Goose Creek is the most developed of the six. It would appear that the presence of extensive intertidal marsh is extremely beneficial in maintaining the equilibrium in the creek, even though it would appear that most of the nutrients are coming through the groundwater.