Hydrothermal Exploration by AUV: ABE in the Lau Basin and South Atlantic
Abstract
The ABE autonomous vehicle has been used to search for and locate new sites of hydrothermal activity on 3 cruises, to the Lau Basin (2004) and the southern Mid-Atlantic Ridge (2005, 2006). Over the course of these expeditions we have consistently and successfully employed a three-phase strategy to locate new sites of hydrothermal activity by: i) mapping non-buoyant hydrothermal plumes using optical backscatter and Eh sensors; ii) intercepting buoyant hydrothermal plumes using optical back-scatter, Eh and temperature sensors (together with thruster data and/or physical displacement of the vehicle from a pre-programmed survey depth); iii) photographing active vents and their chemosynthetic ecosystems. To date the approach has led to the discovery of 13 discrete sites of active venting during the course of 3 research cruises. Most recently, at 5- 10°S on the Mid-Atlantic Ridge, we were able to locate 6 new sites of hydrothermal activity in 9 ABE dives. This included one series of dives in which three vent-sites were located within a 200m x 200m survey that were subsequently visited and sampled by an ROV within 12 hours of completion of our ABE dives. Using LBL navigation, those sites were found to have been accurately located to within <5m, 0.9m and 1.2m respectively. In the Lau Basin our first use of this approach contributed directly to the location of at least four new hydrothermal fields. On the Mid-Atlantic Ridge we have subsequently located the hottest vents on record (407°°C at 3000m depth), completed a time-series photo-study of recent lava-flows that have inundated a low-temperature chemosynthetic community, and discovered a new, extremely vigorous, tectonically-hosted hydrothermal system (8°°S MAR) which appears to be uncolonised by megafauna 2 years after its hydrothermal plume signals were first detected (Devey et al., EOS, 2005).
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFMOS33A1681G
- Keywords:
-
- 0450 Hydrothermal systems (1034;
- 3017;
- 3616;
- 4832;
- 8135;
- 8424);
- 3017 Hydrothermal systems (0450;
- 1034;
- 3616;
- 4832;
- 8135;
- 8424);
- 4832 Hydrothermal systems (0450;
- 1034;
- 3017;
- 3616;
- 8135;
- 8424);
- 8135 Hydrothermal systems (0450;
- 1034;
- 3017;
- 3616;
- 4832;
- 8424);
- 8424 Hydrothermal systems (0450;
- 1034;
- 3017;
- 3616;
- 4832;
- 8135)