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Massachusetts Sea-Floor Mapping Project Expands to South Shore and Cape Cod Bay
Since its beginning in 2003, the cooperative sea-floor-mapping project in Massachusetts has mapped the geology of 897 km2 (346 mi2) of the coastal ocean, mostly inside the 3-mi limit of State waters. The project, jointly undertaken by the U.S. Geological Survey (USGS) and the Massachusetts Office of Coastal Zone Management, has expanded to cover new areas this year and brought in several new partners. We recently welcomed Kathryn Ford of the Massachusetts Division of Marine Fisheries to the USGS Woods Hole Science Center, where she now spends part of every week integrating geologic-framework information from this project into her studies of marine habitat. In addition, Duncan FitzGerald and Christopher Hein of Boston University are contributing their expertise toward understanding and modeling the processes that control the mapped distribution of sediment on the inner shelf.
The initial phase of mapping (2003-05) was focused on areas extending northward from Boston Harbor to the New Hampshire-Massachusetts State line (see Sound Waves article, "USGS, State of Massachusetts, and NOAA Cooperate to Map Sea-Floor Geology Off Massachusetts Coast"). Water depths were mostly in the 5- to 40-m range but locally included areas as much as 90 m deep. Various geophysical techniques were used to map the inner shelf, including interferometric and multibeam sonars (to map bathymetry), sidescan sonar (to map substrate type), and compressed-high-intensity-radar-pulse (CHIRP) seismic-reflection profiling (to map sediment thickness and structure). Data from multibeam and sidescan sonars were also provided by the National Oceanic and Atmospheric Administration (NOAA) to augment USGS efforts in Boston Harbor. Sediment sampling and bottom photography were used to validate or "ground truth" the remotely sensed geophysical data. Results of the first phases of this project are available in two USGS Open-File Reports:
The latest phase of mapping began in August 2006 with a 3-week research cruise aboard the Megan T. Miller. The 100-ft vessel was outfitted with geophysical systems and two mobile laboratories that allowed for data acquisition and onboard processing in near-real time. The survey focused on shallow-water (less than 50 m deep), nearshore areas along the South Shore coast from Hull to Duxbury, where we collected more than 2,300 km of trackline geophysical data covering an area of 270 km2. The scientific crew included Bill Danforth, Emile Bergeron, Walter Barnhardt, Wayne Baldwin, Maianna Hanshaw, and Elizabeth Pendleton on the first leg (Aug. 1-13) and Dave Foster, Chuck Worley, Tom O'Brien, Seth Ackerman, Emily Himmelstoss, and Sandy Baldwin on the second leg (Aug. 13-23). The weather was kind to us, but once again, the success of the cruise depended on the "A-team" of technicians from the USGS Marine Operations Facility. From the first day until the last, they overcame a seemingly endless series of failed air conditioners, global-positioning-system (GPS) navigation shutdowns, unplanned losses of power, broken sonar side-mounts, and an ocean full of gear-snagging lobster pots. Next year, three cruises are planned as the project expands southward into Cape Cod Bay to complete the geophysical mapping and acquire bottom samples and cores. Ultimately, the maps and data layers generated by this project will provide a physical framework for marine scientific research and resource management in the Massachusetts coastal zone. Published reports, preliminary maps, and project updates are posted on the Woods Hole Science Center project Web site.
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in this issue:
Effects of Urbanization on Nearshore Ecosystems in Puget Sound Studying the Elwha River in Preparation for Dam Removal Sea-Floor Mapping Project Expands to South Shore and Cape Cod Bay Earth Science Week Celebration in Menlo Park, CA Google Maps View of Western Coastal and Marine Geology Projects Benthic Sponge Taxonomy Course at Mote Marine Laboratory USGS Team Receives Service to America Medal In Memoriam: Terry Bruns, 1946-2006 |