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USGS, State of Massachusetts, and NOAA Cooperate to Map Sea-Floor Geology Off Massachusetts Coast
Researchers at the U.S. Geological Survey (USGS) Woods Hole Science Center are producing high-resolution maps of the sea-floor geology off the Massachusetts coast, with a focus on the nearshore region in water depths of less than 40 m. The mapping program is a cooperative effort involving the USGS, the Massachusetts Office of Coastal Zone Management (CZM), and the National Oceanic and Atmospheric Administration (NOAA). The need for high-resolution geologic and bathymetric maps is driven by ongoing management concerns about declining fisheries and the impacts of offshore construction projects (for example, pipelines, wind farms, and liquified natural-gas terminals). The maps are an important first step toward protecting essential fish habitat, delineating marine reserves, and assessing changes in habitat due to natural or human impacts. Scientific questions focus on (1) clarifying the postglacial history of sea-level change in the region, (2) reconstructing coastal environments and quantifying rates of change over the past few thousand years, and (3) calculating a sediment budget for the coastal system, which is undergoing chronic erosion. This mapping project was initiated by USGS scientist Brad Butman in 2002 as a way to prepare companion maps to those already produced for the Stellwagen Bank National Marine Sanctuary and western Massachusetts Bay (see URL http://woodshole.er.usgs.gov/project-pages/coastal_mass/). As part of the project, surveys of the inner continental shelf have been carried out in three areas that were identified as high-priority areas by local, State, and Federal agencies:
These areas extend northeastward from Boston Harbor to the New Hampshire-Massachusetts State line, and offshore from the coast to the 3-mi limit of State waters. Water depths are mostly in the 5- to 40-m range but locally include areas as much as 90 m deep. Overall, approximately 450 km2 of the inner shelf has been mapped at 1:25,000 scale, using interferometric and multibeam sonars (to map bathymetry), sidescan sonar (to map substrate type), and chirp seismic-reflection profiling (to map sediment thickness and structure). Sediment sampling and bottom photography and video were used to validate or "ground truth" the remotely sensed geophysical data. The State of Massachusetts recently committed an additional $1 million toward mapping that will focus on Cape Cod Bay starting in 2006 and possibly expand to other areas of State waters in subsequent years.
Walter Barnhardt and Brian Andrews (USGS), along with Seth Ackerman (CZM), have run three research cruises since 2003, most recently on the research vessel Connecticut in September 2005. This latest survey mapped shallow-water areas between Cape Ann and Salisbury Beach. We collected more than 1,000 km of geophysical tracklines and occupied 93 stations for sampling and photography. Though constantly challenged with balky equipment, USGS operations wizards Emile Bergeron, Bill Danforth, and Chuck Worley kept the systems running through some long nights. Special commendation goes to Chuck, master and commander of the Woods Hole Science Center's newly acquired remotely operated vehicle (ROV). The one-armed little robot passed its first test, retrieving a sound-velocity profiler that had spent several nights alone on the sea floor after the line normally used to retrieve it broke. Collaborators Chris Hein and Duncan Fitzgerald of Boston University also assisted in the survey. The infamously rough weather of the Gulf of Maine was kind to us—only 2 days out of 16 were lost when the remnants of Hurricane Ophelia roared through the region. Results of the first phase of this mapping project (Nahant to Gloucester) are currently in review as USGS Open-File Report 2005-1293. (This first phase was described in the Sound Waves article, "High-Resolution Geologic Mapping of the Shallow Sea Floor off Massachusetts.") Preliminary maps and other data are posted on the Woods Hole Science Center Web site at URL http://woodshole.er.usgs.gov/project-pages/coastal_mass/.
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in this issue:
special feature: Offshore Impacts of Hurricane Katrina Sediment-Toxicity Studies in Western Long Island Sound Sea-Floor Geology Off Massachusetts Coast Alvin Dives to Deep-Water Coral Habitats
Briefing on Coastal Research in Hawai'i USGS Research on the Kona Coast, Hawai'i
Native-Plant Landscaping in Florida
Dec. 2005 / Jan. 2006 Publications List  |
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U. S. Department of the Interior | U.S. Geological Survey
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