HR: 0800h
AN: OS51B-0474    [Abstracts]
TI: Recent Advances in Deep-Sea in situ Geochemical Measurements by ROV Deployed Laser Raman Spectroscopy.
AU: * Peltzer, E T
EM: etp3@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95076, United States
AU: Henthorn, R
EM: henthorn@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95076, United States
AU: Hester, K C
EM: khester@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95076, United States
AU: Kirkwood, W J
EM: kiwi@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95076, United States
AU: Rosal, J
EM: jrosal@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95076, United States
AU: Salamy, K A
EM: salamy@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95076, United States
AU: Scholfield, J
EM: scji@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95076, United States
AU: Shane, F F
EM: shfa@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95076, United States
AU: Sherman, A D
EM: alana@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95076, United States
AU: Walz, P M
EM: wape@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95076, United States
AU: Brewer, P G
EM: brpe@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95076, United States
AB: Raman spectroscopy is a valuable analytical technique for making in situ geochemical measurements. It is applicable to liquids, solids and gases; requires little or no sample preparation; and is rapid with typical analysis times of several minutes or less. These features combine to make it an ideal technique for deployment and use on remotely operated vehicles in a variety of applications. We report results from our second generation laser Raman spectrometer (DORISS2), developed in conjunction with Kaiser Optical Systems, Inc., which is both lighter and more robust than the original design. Packaged within a single titanium pressure housing rated to 4000m, DORISS2 has a floating optical bench which minimizes misalignments and preserves instrument calibration both during and between dives. The pressure compensated fiber optic cables have improved signal strength from 8% to 88% at 1024 m greatly reducing the time required to acquire a sample spectrum and allowing the detection of lower concentrations of trace components. Development of the precision underwater positioner (PUP) has enabled the spectroscopic analysis of opaque targets where a focusing precision of +/- 0.1 mm is required. This has allowed us to investigate the composition of authigenic minerals (such as hydrothermal vent precipitates) and gas hydrates in their native and undisturbed condition, such as the massive outcrops on the seafloor at Barkley Canyon, or to inspect the fine-scale inhomogeneities that occur in seafloor synthesis experiments conducted in Monterey Bay. The recent development of a single axis positioner (SAP) has allowed us to use DORISS2 when payload weight is an issue, in places where the seafloor is too steep to safely deploy PUP, or where operational conditions (such as an overhanging ledge) are too restrictive and where PUP does not fit. The SAP adds a new degree of flexibility we have not previously had and has even permitted the analysis of scale carotenoids in a live rock fish with no apparent harm to the organism.
DE: 1034 Hydrothermal systems (0450, 3017, 3616, 4832, 8135, 8424)
DE: 1042 Mineral and crystal chemistry (3620)
DE: 1050 Marine geochemistry (4835, 4845, 4850)
DE: 1094 Instruments and techniques
DE: 4294 Instruments and techniques
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting