A New Towed Digital DeepSea Camera and Multi-Rock Coring System: The WHOI TowCam
Abstract
This year, a team of engineers at the Woods Hole Oceanographic Institution (WHOI) developed and successfully tested a new, digital deep-sea camera system as part of a NSF equipment development grant. The system has been used during two expeditions, one to the Galapagos Rift, and the most recent one to the Hess Deep. To date it has acquired nearly 20,000 digital seafloor images. The new WHOI Towed Digital Camera and Multi-Rock Coring System (TowCam) is an internally recording digital deep sea camera system that also permits acquisition of volcanic glass samples using up to six rock cores in conjunction with CTD water properties data. The TowCam is towed on a standard UNOLS coaxial CTD sea cable, thereby permitting real-time acquisition of digital depth and altitude data that can be used to help quantify objects in the digital images. The use of the conducting sea cable and CTD system also permits triggering of six rock core units on the sled so that discrete samples of volcanic glass can be collected during a lowering. By operating either at night in between Alvin dives, or during other seagoing programs, photographic information of the seafloor can be recorded for near real-time analysis and for planning subsequent Alvin dives or other sampling and surveying programs. The new WHOI TowCam is a self-recording, deep-sea towed camera system rated to 6000m. It is capable of remotely taking 1000 high-resolution color digital photographs on each lowering at intervals of 10-60 sec, while being towed 5-7m above the bottom at speeds of up to 1/2 knot. The digital camera (DigiSeaCam) was developed by DeepSea Power and Light of San Diego, CA and uses a 3.3 Megapixel Nikon995. The onboard CTD (SeaBird25) permits real-time display and recording of digital depth, altitude and other standard CTD sensors (e.g. conductivity, temperature, turbidity), and provides connectivity to the pylon that permits triggering of the rock corers. A strobe monitor connected to a spare serial port in the SBE25, indicates when the strobes are fired. This is displayed on the laptop computer in the ship's lab and provides real-time verification that the camera is functioning and strobes are firing. The system is also equipped with six specially designed rock core winches that permit the user to take discrete samples of volcanic glass by triggering the CTD deck unit and pylon, in much the same way as a CTD Niskin bottle is triggered on a rosette system. When a corer is triggered via the SBE33 Deck Unit and plyon, controlled from the CTD laptop, the corer winch starts turning, and in so doing, the 8 lb. wax-coated stainless steel core head is released and free-falls to the seafloor on a 10m, 200 lb. test, monofilament tether. The core head bounces on the lava flow and is dragged over it as the TowCam continues its traverse, thereby breaking off chips of glass and embedding them in the wax. Each corer winch is designed to reel-up the tether in approximately 4 min, however, the amount of time that the core head is actually in contact with the seafloor varies depending on the altitude when deployed. Nominally, at 5m altitude, the core head is in contact with the seafloor for about 1-1.5 minutes. More information is available for the TowCam at: http://www.whoi.edu/marops/support_services/list_equip_towed_camera.html
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2002
- Bibcode:
- 2002AGUFM.T11C1263B
- Keywords:
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- 8135 Hydrothermal systems (8424);
- 8194 Instruments and techniques