INTRODUCTION

Long Island Sound is a major East-Coast estuary that lies near the most densely populated region of the United States (fig. 1). More than 8 million people live in the Long Island Sound watershed and millions more use the Sound each year for recreation. Fishing, recreational activities, and commercial benefits have an estimated annual value to the regional economy of over $5 billion. Because of the enormous surrounding population, Long Island Sound is stressed by human wastes and contaminants that flow into the estuary. Over a billion gallons of treated effluent are discharged each day into the Sound from treatment plants, and toxic chemicals have been introduced into the Sound from industrial sources, agricultural and urban runoff, power plant and vehicle emissions, and pesticide usage. These inputs have caused contamination of bottom sediments and degradation of benthic habitats.

The studies and data contained on this CD-ROM (Compact Disk - Read Only Memory) were initiated to address marine geologic processes that are essential in understanding the benthic environmental problems of the Sound. Since 1982, the USGS, in cooperation with the State of Connecticut, has developed a good understanding of the shallow geologic framework of the basin and, most recently, has shown that the modern sea floor characteristics often change over short distances and are more complex than existing portrayals in the literature. What is lacking for the Sound concerning its environmental problems are: (1) an understanding of the modern sedimentary processes in local areas and throughout the system that have controlled the transport of bottom sediments and the formation of related habitats; (2) a regional perspective of the bottom sedimentary environments that provides a basis for numerous future interdisciplinary studies and management decisions; and (3) a basin-wide synthesis of contaminant inventories, sinks, transport pathways, and accumulation rates. These are the major objectives of this research program.

This CD-ROM contains an archive of sidescan sonar, high-resolution seismic-reflection, bathymetric, sediment (texture and geochemistry), biologic, surficial geologic and bibliographic data from Long Island Sound. These data and interpretations presented herein were collected, compiled, and produced in cooperation with the State of Connecticut, Department of Environmental Protection, Geological and Natural History Survey; the University of New Haven; the U.S. Environmental Protection Agency; the U.S. Army Corps of Engineers; the U.S. Coast Guard; and the New York State Division of Coastal Resources.