Acquisition of a laser Raman spectrometer for deep-sea studies
Lead Scientist/Project Manager: Peter Brewer
Lead Engineer: George Malby

Colleagues: Jill Pasteris (Washington University), Keith Kvenvolden (United States Geological Survey/MBARI adjunct scientist), Kurt Buck, Charles Paull, Edward Peltzer, Gernot Friederich.

In this new project we seek to extend MBARI’s deep-sea measurement capability by adding Raman spectroscopy to the suite of tools available for both laboratory and in situ work. This is a powerful, nondestructive, tool for obtaining quantitative vibrational data on a wide variety of solutions, and solids, and under extreme conditions. It may be used both in the bulk solution mode, and for the microscopic analysis of small particles and fluid inclusions. MBARI’s principal observing tools, its ROV systems, are well adapted to deploy this instrumentation, which is of interest to many scientists.

In many ways this extends the present broad projection of visible light to interrogate the scene for the scientist to the sophisticated use of the returned scattered (and thereby wavelength shifted) signal from intensely focused laser light to yield specific information on the chemical, and physical, characteristics of the target. Common examples of solution vibrational data are those from CO₂, HCO₃, CO₃, SO₄, NO₃, PO₄, SiOH₄ etc., although detection limits are yet well above background sea water levels other than for SO₄. It is an advantage that simple dissolved ions (Na, Cl, K, Mg etc.) are not seen. One of the prime uses of this tool is in our investigations of the changing cage occupancy of the hydrates formed in our in situ studies.