Underneath the surface of Long Island Sound exists a wide range of seafloor habitats—from the shallow, sandy bottom in the Narrows near New York City, to the deep and rocky recession in the Race near Fishers Island. Mapping the seafloor provides a framework to better understand and manage the resources dependant on these diverse habitats.
Scup near Mason Island. Photo by Robert DeGoursey, UConn.
In an effort to better understand, describe, and analyze these seafloor (or “benthic”) environments federal and state agencies, regional organizations, and academic institutions use high resolution underwater acoustic and imaging techniques to characterize and map specific geographic locations.
A 2004 settlement between the states of Connecticut and New York, two power companies, and a cable company is providing funding for additional seafloor mapping. The settlement resolved a permitting dispute relating to two electrical cable crossings of Long Island Sound. As part of the settlement, the companies agreed to contribute $6 million to a Long Island Sound Research and Restoration Fund as a condition for its permit. In 2004, the Long Island Sound Study Policy Committee signed a Memorandum of Understanding on administering the fund for research and restoration projects to enhance the waters and related natural resources of Long Island Sound. In 2006, the Long Island Sound Study Policy Committee signed a second Memorandum of Understanding formally establishing a framework for the fund’s use. The Policy Committee agreed that the Fund be used to:
Support new projects and activities that enhance Long Island Sound.
Promote improved scientific understanding of the biological, chemical, and physical effects of existing or potential cable and pipeline crossings and mitigation of their impacts.
Emphasize benthic mapping as a priority need, essential to an improved scientific basis for management and mitigation decisions.
Modern acoustic technologies are generating satellite-like images of the complex subsea topography of the Sound.
The Policy Committee also established a Cable Fund Steering Committee, comprised of representatives of the EPA Region 1 and Region 2 offices, the New York State Department of Environmental Conservation, The Connecticut Department of Energy and Environmental Protection, and Connecticut and New York Sea Grant Programs, to administer the fund.
The Long Island Sound Seafloor Habitat Mapping Initiative
View the photo gallery to find out about the work being done as part of the Seafloor Mapping Initiative.
Exploring the undersea life of the Sound began in 2012 with the mapping of the Long Island Sound seafloor using “multibeam sonar echosounder” technology. Much of the work was done by scientists on board the NOAA Ship Thomas Jefferson.
The sonar equipment collects bathymetry (water depth) and “backscatter” data. Backscatter is a measure of the strength of the reflection of the acoustic beam from the seafloor. If the sound hits soft bottom such as a muddy surface most of the sound is absorbed producing darker colors, while hard bottoms such as boulder or gravel reflect much more sound and generates lighter tones.
While acoustic mapping provides the satellite scale view of the seafloor, physical sampling and high resolution imagery are necessary to “ground truth” the sonar images. The US Geological Survey’s SEABed Observation and Sampling System (SEABOSS), is a key platform that collects sediment samples and imagery providing information on what lives in and on the seafloor.
In areas with hard substrates where sampling isn’t possible, an underwater Remotely Operated Vehicle (ROV) is used to explore and navigate the rugged terrain to take high definition video and photographs.
The data and images collected from these research cruises are used to create maps such as this map documenting the amount of infauna (organisms living in the sediments) and epifauna (organisms living on the surface of the seafloor) in the Stratford Shoals area of the central Sound.
The maps and other research products developed from the research cruises are available on a new website for the Long Island Sound Habitat Mapping Initiative. There also are multimedia products for non-scientists to understand and appreciate what’s below the surface of the Sound. See the rest of this gallery for examples.
There are ArcGIS story maps that provide presentations on how the research is being conducted.
Other story maps describe the varied and spectacular habitats researchers are documenting.
There also are slide shows with high resolution images such as this photo of a winter skate gliding across a cobble bottom in the eastern Sound.
And there are links to videos on YouTube of the research cruises. This video was taken during a research cruise in which the Kraken2, an ROV, explored boulder habitat in eastern Long Island Sound.
So far research teams for the Habitat Mapping Initiative have explored the Stratford Shoals area in the central Sound (Phase 1) and eastern Long Island Sound (Phase 2). Next up is a section of western Long Island Sound.
Here is the list of partner organizations that have worked on the initiative:
University of Connecticut
University of New Haven
United States Geological Survey
Lamont Doherty Earth Observatory of Columbia University
Stony Brook University
Queens College
NOAA National Centers for Coastal Ocean Science
Connecticut Department of Energy & Environmental Protection
New York State Department of Environmental Conservation
New York State Department of State
The Habitat Mapping Initiative is located on the University of Connecticut website at: https://lismap.uconn.edu
To learn more about the Long Island Sound Seafloor Habitat Mapping Initiative go to Habitat Mapping page on the the University of Connecticut website.
Long Island Sound Seafloor Mapping Program References
Below is a list of reference materials to learn more about how the history of the Long Island Sound Seafloor Mapping Program began, and about seafloor mapping in general. Another good reference on this history of the program is the October 2013 issue of Sound Update.
Comprehensive Assessment and Report, Part II, Environmental Resource and Energy Infrastructure of Long Island Sound, Taskforce on Long Island Sound, Pursuant to State of Connecticut Public Act No. 02-95 and Executive Order No. 26, June 3, 2003.
Long Island Sound Symposium: A Study of Benthic Habitats, the Connecticut Academy of Science and Engineering for the Connecticut Energy Advisory Board, Nov. 2004.
Environmental Impact Statement for the Designation of Dredged Material Disposal Sites in Central and Western Long Island Sound, Connecticut and New York. US Environmental Protection Agency, New England Region, April 2004.
"Why We Map"
A striped sea robin, Prionatus evolans, cruises boulder habitat in search of small crustaceans and other invertebrate prey.
“What lies below this blue horizon remains unseen and therefore largely unknown to most of society. The seafloor habitats of the Sound are as diverse as those on land and similarly harbor a diversity of life that is essential to our well-being.”
From “Why We Map,” a web page in the UConn Long Island Sound Seafloor Habitat Mapping website.
ROV Exploration of Long Island Sound
A video showing seafloor habitats in eastern Long Island Sound, taken by an underwater Remotely Operated Vehicle. It appears on the Long Island Sound seafloor Habitat Mapping Initiative website.
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