HR: 1340h
AN: B13A-0190    [Abstracts]
TI: New Techniques for Hydrothermal Exploration: In Situ Chemical Sensors on AUVs - Preliminary Results From the Lau Basin
AU: * German, C R
EM: cge@soc.soton.ac.uk
AF: Southampton Oceanography Centre, European Way, Southampton, SO14 3ZH United Kingdom
AU: Connelly, D P
EM: dpc@soc.soton.ac.uk
AF: Southampton Oceanography Centre, European Way, Southampton, SO14 3ZH United Kingdom
AU: Prien, R D
EM: rdpr@soc.soton.ac.uk
AF: Southampton Oceanography Centre, European Way, Southampton, SO14 3ZH United Kingdom
AU: Yoerger, D
EM: dyoerger@whoi.edu
AF: Woods Hole Oceanographic Institution, Water Street, Woods Hole, MA 02543 United States
AU: Jakuba, M
EM: mjakuba@whoi.edu
AF: Woods Hole Oceanographic Institution, Water Street, Woods Hole, MA 02543 United States
AU: Bradley, A
EM: abradley@whoi.edu
AF: Woods Hole Oceanographic Institution, Water Street, Woods Hole, MA 02543 United States
AU: Shank, T J
EM: tshank@whoi.edu
AF: Woods Hole Oceanographic Institution, Water Street, Woods Hole, MA 02543 United States
AU: Edmonds, H N
EM: edmonds@utmsi.utexas.edu
AF: Marine Science Institute, University of Texas at Austin, Port Aransas, TX 78373 United States
AU: Langmuir, C H
EM: langmuir@eps.harvard.edu
AF: Department of Earth and Planetary Science, Harvard University, Cambridge, MA 02318 United States
AB: Less than one quarter of the global ridge-crest has yet received even cursory investigation for the presence or absence of hydrothermal activity. To improve exploration efficiency, particularly at high latitudes, new methodologies independent of tethered vehicles are required. To that end, we have begun the use of in situ chemical sensors allied to the increasing capabilities of autonomous underwater vehicles. Here, we present first results from our most recent efforts aboard the second R2K cruise to the Lau Basin (C.Langmuir, PI; Autumn 2004) to (a) map non-buoyant hydrothermal plumes, (b) intercept buoyant hydrothermal plumes and (c) locate and image novel hydrothermal fields on the seafloor. The AUV used for this work is ABE and the sensors deployed are direct extensions of the in situ Fe/Mn sensor deployed previously on SOC's AUTOSUB to investigate seasonally-reducing waters in Loch Etive, NW Scotland. Each in situ instrument comprises an electronics package that contains a tattletale control system with a flash memory card for on-board logging and a chemical manifold, consisting of a series of valves, pumps and a colorimetric cell. Analysis of iron is enabled by the determination of the coloured complex formed between iron II and ferrozine, manganese uses the colour change of PAN in the presence of reduced manganese. The system includes capacity for switching between sample, blank and two on-board samples for "in flight" calibrations with blanks and standards held in medical bags, outside of the pressure-balanced manifold, to attain in situ water-column temperatures. An in-line filter prevents large particle clogging and detection limits for both iron II and manganese II are ca.2nM.
DE: 4805 Biogeochemical cycles (1615)
DE: 4808 Chemical tracers
DE: 4832 Hydrothermal systems
DE: 4835 Inorganic marine chemistry
DE: 4875 Trace elements
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting