Multi-beaming and mapping . . .
June 5, 2007

We arrived at our highest priority location around 1600 yesterday and immediately began to use the R/V Nancy Foster’s multi-beam sonar.  Our first full transect will take about 50 hours and we are now completing the bottom half of that transect.  The multi-beam survey is a 24/7 operation.  Three multi-beam technicians and 5 assistant technicians have been working around the clock in 5 to 8 hour shifts.  As expected, we mapped areas that appear to be coral pinnacles – some up to 70 meters from the seabed!

Multi-beam is a type of sonar that uses several overlapping beams to obtain high resolution bathymetry (or depth) and other details, such as the hardness of the bottom, which is also called “backscatter” or “reflectance.”  Multi-beam sonar provides wide “swaths” of closely spaced data points and complete coverage of our target area.

Every four hours we deploy a conductivity, temperature, and depth sensor or “CTD”, which is an instrument that collects temperature and salinity data.  CTDs also have the capability to collect data on fluorescence and take water samples at different depths.  We plan to deploy an Acoustic Doppler Current Profiler (ADCP) later today, which will provide information on the subsurface currents, which the AUV technicians will use calibrate the multi-beam data and plan the AUV flight path.

We anticipate finishing this transect by 2000 this evening and we will begin our transit to an area off Miami where we are scheduled to conduct both 30 hours of AUV survey and another 8 hours of multi-beam survey.  The science team and crew eagerly await the Eagle Ray’s first plunge in the water for this mission!

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Meet the Science team and Crew