Location of bottom still imagery along with images collected during field activity 2011-015-FA by the U.S. Geological Survey and Massachusetts Office of Coastal Zone Management offshore of Massachusetts around Cape Cod and the Islands in September 2011 (JPEG images, point shapefile, and CSV file)

Bottom imagery was acquired using the large SEABOSS, where operational, or the ship's Van Veen grab sampler equipped with a GoPro HD HERO camera. The observations from video and still cameras and the sediment data are used to explore the nature of the sea floor and, in conjunction with high-resolution geophysical data, to make interpretive maps of sedimentary environments and validate acoustic remote sensing data. The SEABOSS incorporates two video cameras (one forward-looking so that a shipboard operator can monitor for proper tow depth and obstacles, and one downward-looking, a Kongsberg Simrad OE1365 video camera in this setup, that overlaps with the field of view of the still camera), a still camera (Konica Minolta DiMAGE A2 in this setup), and a modified Van Veen sediment sampler. The elements of this particular SEABOSS system are held within a stainless-steel frame that measures 1.1 x 1.1 meters. The frame has a stabilizer fin that orients the system as it drifts over the seabed. The OSV Bold occupied one of the target stations and the SEABOSS was deployed off the vessel's A-frame on the stern of the ship. The vessel and sampler drifted with wind and current for up to a few minutes to ensure a decent image with a clear view of the sea floor and then at most stations the sea floor was sampled with the SEABOSS's integrated Van Veen grab. Sediment samples were only attempted in areas where collecting a sample would not damage the SEABOSS; therefore, no samples were collected in areas with a cobble, boulder, or rocky seabed, as identified in real time using the top-side live video feed. At some sites, samples were attempted one or more times in what appeared in the real-time video as sand or mud, but no sample was successfully collected. The system was then raised and recovered to the deck of the survey vessel. The Konica Minolta digital photos were saved to the camera's SD memory card and periodically downloaded from the camera during the survey. The camera time was set to UTC; calibration photographs with the navigation system indicate that the time offset drifted by up to 67 seconds throughout the survey and this time offset was corrected for in the imagery processing. Photos taken in the water column, on deck, or without a clear view of the sea floor were deleted. The still camera was occasionally malfunctioning, so some stations did not have any usable photographs. For these stations, still-image frame grabs were captured from the bottom video to supplement this dataset. Bottom video was recorded from the Kongsberg Simrad OE1365 downward-looking video camera on Digital8 tapes and backup DVDs. The SEABOSS was only operational for 246 of the 322 stations occupied during this survey. Since the SEABOSS's still camera was occasionally malfunctioning, use of the SEABOSS was halted partway through the survey and the remaining stations were occupied using the ship's Van Veen grab sampler equipped with a GoPro HD HERO camera and dive lights. The ship's sampler was deployed off the vessel's A-frame on the stern of the ship and lowered until the sea floor was sampled. There was no top-side live video feed, so the vessel and sampler did not drift over the seabed, video was not collected, and samples were attempted at all stations occupied using the ship's Van Veen grab sampler. The GoPro digital photos were saved to the camera's SD memory card and periodically downloaded from the camera during the survey. The GoPro was set to capture photographs at a one- or two-second interval. Because the frame was stationary on the seabed, only one GoPro photograph was chosen to represent the sea floor at each station location. The GoPro camera time was set to local time (UTC-04:00) and was not assessed for accuracy or used for geolocating the photos; rather, the time of the station's sediment sample grab was used for the GoPro photos' GPS time and to geolocate the photos. DGPS navigation from a Garmin GPSMAP 76CSx receiver was logged through a Microsoft HyperTerminal (version 5.1) session on a Dell Latitude D820 laptop computer running Windows XP SP2 via serial cable. The DGPS was set to receive fixes at a two-second interval in geographic coordinates (WGS 84). Log files were saved for each sampling watch in ASCII text format.