Project SR12-006: benthic invertebrate community monitoring and indicator development for Barnegat Bay-Little Egg Harbor estuary: year 2

The Barnegat Bay ecosystem is potentially under stress from human impacts, which have increased over the past several decades. Benthic macroinvertebrates are commonly included in studies to monitor the effects of human and natural stresses on marine and estuarine ecosystems. There are several reasons for this. Macroinvertebrates (here defined as animals retained on a 0.5-mm mesh sieve) are abundant in most coastal and estuarine sediments, typically on the order of 103 to 104 per meter squared. Benthic communities are typically composed of many taxa from different phyla, and quantitative measures of community diversity (e.g., Rosenberg et al. 2004) and the relative abundance of animals with different feeding behaviors (e.g., Weisberg et al. 1997, Pelletier et al. 2010), can be used to evaluate ecosystem health. Because most benthic invertebrates are sedentary as adults, they function as integrators, over periods of months to years, of the properties of their environment. The Barnegat Bay-Little Egg Harbor (BB-LEH) Estuary is heterogeneous with respect to environmental variables that are well known to affect benthic community composition. Salinity and sediment particle size vary throughout the system. Salinity varies locally along the main axis of the estuary in response to ocean water sources (notably at Barnegat Inlet, Beach Haven Inlet, and the Point Pleasant canal) and fresh-water sources (notably Toms River, Metedeconck River, and Cedar Creek). Long-term data collected by the New Jersey Department of Environmental Protection, Bureau of Marine Water Monitoring show that salinity tends to be lower in northern Barnegat Bay (range 0-20) than in central and southern Barnegat Bay and in Little Egg Harbor (range 20 to >28). Sediment particle size, and the inversely correlated sediment organic content, varies from east to west, with fine-grained sediments predominantly present in the western half and coarser sediments in the east. Sediment organic matter content is likely to also vary in response to variations in nutrient loadings throughout the system. Our objective is to develop quantitative measures to relate benthic community structure to variation in these and other environmental properties in BB-LEH Estuary. Benthic invertebrates in the BB-LEH Estuary were sampled comprehensively in 2001 as part of the EPA REMAP and NCA efforts, when 96 stations were sampled. In July 2012 we sampled 100 stations throughout the bay in order to obtain a data set comparable to the sampling density in 2001. In July 2013 we re-sampled these stations, using the same methods, in order to evaluate any short-term temporal change, including potential effects from Hurricane Sandy which struck the New Jersey coast between these two sampling periods.Cover title: "Plan 9: Research, Barnegat Bay--Year 2"