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New York Bight Field Experiment: Recovery Cruise
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Dave Walsh, John Borden, and Rick Rendigs
begin the grappling-hook attempt on tripod B.
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A scientific staff of 14 spent a long April weekend on the R/V Endeavor recovering equipment off
New York City. Led by Chief Scientist Brad Butman (WHFC), the ship left Narragansett, Rhode
Island, with a fairly empty deck on April 14th and returned four days later loaded with tripods, moorings,
and buoys. The recovery operation was the second cruise for the New York Bight Field Experiment. The
first cruise took place in December 1999, during which six tripods and two instrument moorings were
deployed (Figure 1, below). The field experiment was designed to observe sediment transport and
oceanographic circulation in the vicinity of the Hudson Shelf Valley and is part of a joint modeling and
observational effort that will complement geochemical and geologic evidence for down-valley transport
of anthropogenic material.
Figure 1—New York Bight Cruise, April 2000. The April 2000 New York Bight cruise
set out to recover eight instrument packages (triangles) and acquire as many CTD and video/grab
samples as time (and weather) allowed (+'s and x's, respectively).
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Figure 2. Marilyn Buckholtz ten Brink (left), Erin Galvin (middle), and
Sunita Shuh (right) scoop mud from a sediment grab obtained using the SEABOSS system.
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The scientific party made use of nocturnal ship time, when mooring operations were not possible, by taking
video surveys and grab samples and by completing a CTD transect of 10 sample sites along the Hudson
Shelf Valley (Figure 1, above). The sampling crew included Marilyn ten Brink, Courtney Harris, Erin
Galvin, Ben Gutierrez, Sunita Shah (WHFC), and Peter Traykovski (WHOI). Thirty-five grab
samples and accompanying video coverage of the seafloor were obtained using the SEABOSS instrument
(Figure 2), expertly piloted by Dann Blackwood (WHFC). Grab and video sample locations were
chosen either to represent a tripod site or to complement previous sampling efforts. Samples from tripod
sites will be used to calibrate Optical Backscatter Sensor (OBS) readings and Acoustical Backscatter Sensor
(ABS) readings. The other samples will be analyzed for sediment texture and chemistry.
Figure 3. Chief Scientist Brad Butman (foreground) observes the
skill of the USGS and Endeavor crew in bringing tripod A on board.
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Marinna Martini led the mooring crew, which included John Borden, Jessica Cote, Rick Rendigs,
Dave Walsh (WHFC), and Joanne Ferreira (MPFC). The skilled crew worked long days to
recover the six tripods and two instrument moorings (Figure 3) and was successful for all but one tripod.
The "one that got away," tripod B in Figure 1, is located in a muddy area in the middle of the New York
shipping lanes in 55 m of water. Its release mechanism successfully deployed but the line broke when tension
was applied. After recovering the other tripods and moorings, the scientists returned to the site and tried for
several more hours to salvage tripod B by dragging the area with a grapple hook. The tripod was hooked at
least twice and was dragged over 100 m. However, full recovery was not possible before winds rose to
30-40 knots and the ship had to begin its 20-hour transit back to Narragansett.
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Figure 4. Joanne Ferreira (left) and
Jessica Cote (right) began downloading and processing ADCP data during the cruise as soon as
they could retrieve instruments from the tripods.
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Recovered equipment included dozens of instruments that will provide data with which to evaluate circulation
and sediment transport in the New York Bight. Thus far, data recovery appears to be good as USGS scientists
and engineers begin downloading and processing. Among the instruments involved are five Acoustic Doplar
Current Profilers (ADCPs) (Figure 4, at right), two Benthic Acoustic Stress Sensors (BASS), three Modular
Acoustic Velocity Sensors (MAVS), eight Optical Backscatter Sensors (OBS), four transmissometers, 12
sediment traps, and a sediment sampler triggered by wave energy. Peter Traykovski (WHOI)
is downloading and processing data from a Laser In-Situ Scattering and Transmissometry with Settling Tube
(LISST-ST) and two ABSs that were recovered from tripods A and D. The data will be used to characterize
wintertime sediment-transport events over a wide range of substrate types in the bight. The data will also
be used in conjunction with a three-dimensional model of circulation and sediment transport that is being
developed by USGS scientists for the area. The Woods Hole staff hopes this spring or summer to schedule
another grappling-hook effort or use a remotely operated vehicle to recover the missing tripod. They know
its precise location because Marinna was able to "talk" to it and determine its distance
from the ship.
Photos provided by D. Blackwood.
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May 2000
in this issue:
cover story:
NY Bight Cruise
Honduras Coral Reefs
Letter to the Editor
Nat'l Ocean Sciences Bowl Winner
Earth Day, Tampa Bay
Gulf of Mexico
Great Lakes Mapping
Interagency Pollution Work
Edgar Receives RSAS Award
Shinn, Reich, & Hickey Receive SEPM Award
Work With High School Students
New Post-Doc
New ECO Interns at WHFC
Talk by Richie Williams
Ellen Mecray Completes Boston Marathon
Visitors
May Publications List
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U. S. Department of the Interior | U.S. Geological Survey
