The U.S. Geological Survey, in cooperation with the
National Oceanic and Atmospheric Administration and the Connecticut
Department of Environmental Protection, has produced detailed geologic
maps of the sea floor in Long Island Sound, a major East Coast estuary
surrounded by the most densely populated region of the United States.
These studies have built upon cooperative research with the State of
Connecticut that was initiated in 1982. The current phase of this
research program is directed toward studies of sea-floor sediment
distribution, processes that control sediment distribution, nearshore
environmental concerns, and the relation of benthic community
structures to the sea-floor geology.
Anthropogenic wastes, toxic chemicals, and changes in land-use patterns
resulting from residential, commercial, and recreational development
have stressed the environment of the Sound, causing degradation and
potential loss of benthic habitats (Koppelman and others, 1976; Long
Island Sound Study, 1994). Detailed maps of the sea floor are needed to
help evaluate the extent of adverse impacts and to help manage
resources wisely in the future. Therefore, in a continuing effort to
better understand Long Island Sound, we have constructed and
interpreted mulitbeam bathymetric data within specific areas of special
interest. The gridded data presented herein covers a roughly 94 km
square area of the sea floor in the area known as the Race at the
eastern end of Long Island Sound. The original multibeam bathymetric
data were collected during October 2003 as part of charting
applications aboard the NOAA Survey Vessel Thomas Jefferson. A Simrad
EM1002 multibeam system mounted on the hull of this vessel was used to
acquire over 560 km of survey lines from the deeper water (>20 m)
parts of the study area. Two 29-foot launches with hull-mounted Reson
systems were deployed from the ship and were used to acquire an
additional 637 km of survey lines from the shallower areas.
The detailed bathymetic data and their interpretations
serve many purposes, including: (1) defining the geological variability
of the sea floor, which is one of the primary controls of benthic
habitat diversity; (2) improving our understanding of the processes
that control the distribution and transport of bottom sediments and the
distribution of benthic habitats and associated infaunal community
structures; and (3) providing a detailed framework for future research,
monitoring, and management activities. The bathymetric data models also
serve as base maps for subsequent sedimentological, geochemical, and
biological observations, because precise information on environmental
setting is important for selection of sampling sites and for accurate
interpretation of point measurements.