This was an equipment-only grant, designed to provide the investigators with several related items of permanent equipment for use in the rapid response to the Deepwater Horizon oil well blowout. The three items and their applications are:

1. Greenhouse gas analyzer (Picarro G2301) for the determination of methane, carbon dioxide, and water vapor. The main reason for obtaining this instrument was to determine methane in the air and dissolved in the water near the Deepwater Horizon site. Methane was a major component of the material coming out of the blown out well. It is also a natural resource (i.e., the major component of “natural gas”) and a “greenhouse gas” (i.e., a gas that plays a role in the earth’s atmospheric heat trapping). After obtaining the instrument, we quickly developed an air-water equilibration method in order to use it to determine low levels of dissolved methane. We have used the instrument to determine dissolved methane in the northern Gulf of Mexico on several occasions and have seen that with the capping of the well, the dissolved methane levels quickly returned to ambient levels. We are also using the instrument to determine methane in other local waters.

2. Isotopic water analyzer (Picarro L2120-i) for the determination of the ratio of oxygen-18 to oxygen-16 as well as the ratio of hydrogen to deuterium in water molecules. These are naturally-occurring stable isotopes of oxygen and hydrogen. The slight mass differences in the two isotopic forms of the atoms results in various physical, chemical, and biological processes changing the isotopic ratios of materials such as water. Our goal is to use the isotope ratios of these atoms in water as a tracer of different sources of water in the northern Gulf of Mexico. These various waters (both river waters and various offshore seawater masses) have their own characteristic isotopic ratios. Thus, the isotopic analysis should provide us with a tracer of these various water sources. We have collected water samples on our various oil spill cruises for isotopic analysis with this new instrument. We are also collecting water samples from local rivers for future studies. The isotopic analyzer is an interesting piece of equipment because, instead of relying on a traditional mass spectrometry method for measuring the isotope ratios, it utilizes infrared light absorbance determined in a sophisticated way.

3. Diode-array UV-visible spectrophotometer (Agilent G1812AA) for determining light absorbance of aqueous samples as a function of wavelength. This new instrument replaced a 20-year old instrument in our labs that was nearing the end of its serviceable life. The main goal for this instrument was to use it to help characterize the "color" of the dissolved organic matter present in water samples near the wellhead. Colored dissolved organic matter (CDOM) has proven to be an important tracer in determining the nature, transformation and biogeochemical behavior of organic matter in aquatic environments. We have analyzed the light absorbance of samples that were potentially affected by oil contamination. It provides us with a simple, inexpensive, and rapid measurement of some aspects of this contamination.

As part of this project, a number of graduate students as well as an undergraduate and a postdoc, were trained in the use of these new pieces of equipment. Overall, the new equipment advanced our analytical abilities to study the impact of the oil spill, provided us with new opportunities to train students in geochemical analysis, and will continue to help us advance our geochemical research by augmenting our laboratory infrastructure.

Last Modified: 12/26/2011
Modified by: Alan M Shiller