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PECONIC ESTUARY EELGRASS HABITAT CRITERIA STUDY
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PECONIC ESTUARY EELGRASS HABITAT CRITERIA STUDY The main objective of this study is to develop criteria for eelgrass habitat establishment and persistence within the Peconic Estuary utilizing various environmental analyses. The Program evaluated water and sediment quality data to characterize existing conditions within the estuary where eelgrass (Zostera marina) density is highest, lowest, transitional, stressed, and non-existent. The collected data were then compared to criteria from the Connecticut-Long Island Sound Study (LISS) and the Chesapeake Bay Study (CBS). 14 fixed sampling locations were chosen in part based upon historical eelgrass bed density and surrounding land use. Site reconnaissance and aerial photography were used to characterize the stations. Water quality monitoring included salinity, temperature, conductivity, pH, secchi disc, dissolved oxygen, depth and light extinction coefficient. Water samples collected for laboratory analysis include total suspended solids, chlorophyll-a, dissolved inorganic phosphorous, (orthophosphate) and dissolved inorganic nitrogen (NOX and NH3). Additionally, weather data and global position were recorded. Sediment was collected for total organic carbon (TOC) and grain size analysis. An acoustical flow meter was deployed at several locations to get a general picture of hydrodynamic conditions existing where eelgrass beds are non-existing, transitional, stressed and lush. Vector, velocity and temperature of near-bed conditions were recorded. Monitoring of test plots at each of the eight transplant locations assessed the general health of the plants using a relative scale of good, poor or excellent. Additional observations regarding die back, wildlife utilization, and epiphytic growth were also noted. The areas supporting the densest beds, averaged 0.3m -1KD, 3.1 g/l chlorophyll-a, 0.01mg/l DIN, and summer DO of 7.1mf/l. Except for chlorophyll-a, the observed parameters throughout the Peconics fall on average, lower than the estuary averages recommended for the Criteria Requirements for the Chesapeake Bay and the Long Island Sound. In general, water quality conditions are suitable for re-establishment of eelgrass at a two-meter depth only in the eastern portion of the estuary. Additionally, substrate TOC is fairly low within the estuary. The hydrodynamic data indicates typical tidal and wind-influenced occurrences for an estuary within the main bays, peripheral bays and tidal creeks. The larger bays show significant evidence of wind forces predominating with many diurnal pulses. The peripheral bays and large tidal creeks, depending on size and location, fall between wind-driven and tidally influenced.
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Eelgrass Habitat Criteria Study- Volume II, AppendicesEelgrass Habitat Criteria Study- Volume I Narrative (PDF, NA pp, 5926 KB, about PDF)