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gases coming off the hydrate with a lighter
to watch it burn and also to verify that the gases The ship is transiting north tonight to a new location for tomorrow's dive. But we'll return to this Guaymas Basin ridge Monday morning--and hopefully to these gas vents--to deploy the laser Raman spectrometer (LRS) instrument. MBARI post-doc Sheri White has the following update on the LRS.
The laser Raman spectrometer (LRS) hasn't gone down on the ROV yet, but that doesn't mean we haven't been busy with it. The LRS illuminates a sample with green (532 nm) laser light and records the backscattered spectrum. While most of the light is reflected back at the same wavelength, a small amount (~1 out of every 100,000,000 photons) interacts with the molecules of the sample and is shifted in wavelength. The spectrum of the shifted backscattered light is like a finger print of the sample. The LRS can be used to study solids, liquids, and gases in situ. We are hoping to measure both natural gas venting from the seafloor and solid gas hydrates that form in the sediment. We purchased our LRS from Kaiser Optical Systems and modified it for use in the deep ocean. Unfortunately, not all of its components are robust enough for work at sea. Unlike lab-based instruments, sea-going instruments are often subjected to shock and vibrations, and are dissembled and reassembled in pressure-tolerate housings on a regular basis. Modifications often need to be made at sea, where parts cannot be easily obtained.
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