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New York Bight Field Experiment: Recovery Cruise

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fishing for tripod B
Dave Walsh, John Borden, and Rick Rendigs begin the grappling-hook attempt on tripod B.
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.

map of New York Bight cruise
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).

scooping mud from sediment grab
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.
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.

bringing in tripod A
Figure 3. Chief Scientist Brad Butman (foreground) observes the skill of the USGS and Endeavor crew in bringing tripod A on board.
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.

retrieving data
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.
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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NY Bight Cruise

Honduras Coral Reefs

Outreach Letter to the Editor

Nat'l Ocean Sciences Bowl Winner

Earth Day, Tampa Bay

Meetings Gulf of Mexico

Great Lakes Mapping

Interagency Pollution Work

Awards Edgar Receives RSAS Award

Shinn, Reich, & Hickey Receive SEPM Award

Work With High School Students

Staff & Center News New Post-Doc

New ECO Interns at WHFC

Talk by Richie Williams

Ellen Mecray Completes Boston Marathon


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