INTRODUCTION

Benthic communities are an integral component of estuarine systems. The fauna that live on or in the seafloor comprise an important portion of estuarine food webs (e.g. Day et al. 1989) and, as such, their abundance and composition directly or indirectly affect harvestable biological resources in estuaries. Benthic fauna also play an important role in geochemical and physical processes such as sediment reworking and flux of chemicals (Aller 1978, 1982; Aller & Yingst 1978; Rhoads & Boyer 1982; Waslenchuk et al. 1983; Yingst & Rhoads 1978) and, in the context of human impacts, are used as indicators of ecosystem health (Pearson & Rosenberg 1978; Rhoads et al. 1978; Green 1979; Warwick 1986). This portion of the project examined the current status of work on benthic communities in Long Island Sound (LIS) by reviewing information available in the literature and reanalyzing portions of this data. The goal was to develop an ecological characterization of benthic communities in the Sound that can be used as a framework for ongoing management and research efforts. This characterization focuses on depicting not only the general, sound-wide trends in community structure, but also addresses variability in community structure at different spatial scales. The information was then used to develop a model of how benthic communities may respond to both natural and human disturbances to the seafloor. As part of this review, information on the geologic structure of the seafloor of Long Island Sound was also examined. This was done in order to assess a) what is presently known or thought to be the distribution of benthic habitats and b) how information from several different sources might be used to more accurately determine habitat distributions and characteristics.

The benthic habitats in Long Island Sound are diverse and correspondingly have an array of associated communities. These habitats and communities have been the focus of many studies (Chapter 7 of this CD-ROM).  Here, I focus on infaunal soft-sediment communities. Although communities associated with hard bottom habitats (e.g. rocks and outcrops) add to the overall biotic richness of the sound, and can be foci of important ecological processes (e.g. locally enhanced primary production in kelp beds), soft-sediment habitats comprise the greatest area in the Sound. As such, soft-sediment habitats and communities likely play a greater role in the overall ecological and biogeochemical processes of LIS. With respect to work done on soft-sediment communities in Long Island Sound, we can distinguish between studies that have been conducted in intertidal and shallow waters along the coast and those conducted offshore in waters generally > 5 m. Here, I focus on these deeper-water areas. This separation is somewhat artificial and has been made in order to specifically define the scope of the work conducted relative to the goals of the overall project. There have been many studies of inshore areas, conducted by academic researchers (e.g. Welsh et al. 1977, Zajac and Whitlatch 1982a,b), utility companies (Northeast Utilities, United Illuminating) and consultants. This is an important body of work, that should also be examined and analyzed in a systematic fashion to generate a complete ecological picture of soft-sediment communities in the Sound. Of the studies conducted in the Sound itself, we can further distinguish between surveys conducted over relatively larger spatial scales and studies which addressed more specific aspects of infaunal community structure and dynamics on smaller spatial scales (see below). The approach here was to primarily review and assess the large-scale surveys of infaunal community structure conducted in the Sound, and use information from smaller-scale studies to supplement this information and provide information on process that may influence community dynamics at various spatial and temporal scales.

The specific goals of this portion of the project were to 1) develop a cohesive view of benthic habitats and communities in LIS, integrating the results of the studies that have been conducted and identifying any gaps in information and understanding, and 2) develop a set of preliminary maps in a benthic GIS for the Sound that could be used to display the information and query the data base in the course of further research and management efforts. The review and maps generated by this work will hopefully provide several benefits relative to the objectives of the LIS Research Fund and management of the sound by the DEP in general. These include:

1) a systematic approach to characterization of the Sound's benthic habitats and bottom communities providing continuity and points of reference,

2) a more in-depth assessment than currently is available which could be used for present management needs as more detailed and expanded coverages are compiled,

3) the maps can guide present and future efforts in detailed mapping of the sound's benthic environment and associated biota, by allowing for identification of areas that are particularly important with regard to management issues and/or areas that are, or are not, well characterized,

4) as an initial information compilation and analysis effort it may save research and management funds by avoiding duplication of efforts, and

5) it can assist research and management efforts centering on other aspects of LIS by providing basic background information on the benthic environment.