The laboratory is used exclusively for stable isotope research into biosignatures and for other astrobiology topics. Recent work has progressed in three directions.
- As part of one of the NASA Astrobiology Institute (NAI) research groups we have developed a new application of an established technique. Fossil carbonate shells contain trace amounts of sulfate from the seawater in which the organisms lived. Geochemists extract the “carbonate associated sulfate” (CAS) to investigate changes in global geochemical cycles in the past. We have measured isotopic compositions of CAS from carbonate minerals produced during sediment burial to understand the history of microbial-ecology of sediment porewaters.
- We were part of the team that discovered the deepest hydrothermal vents on Earth in the Mid-Cayman Trough in 2009. Finding out whether deep sea, hydrothermal vent biological communities can be self-sufficient in the total absence of sunlight is an important part of investigating the potential for life in the deep ocean of Europa. To that end we have investigated the food chain using natural, stable isotopic tracers and have shown that it is independent of surface, photosynthetic input.
- Minerals formed by evaporation of water can retain as part of their structure the water in which they were growing. Crystals of such minerals grow around a nucleus and the growth zones preserve successive samples of the water as evaporation progresses. The relationship of hydrogen and oxygen isotopes in such waters can be interpreted to indicate the paleo-humidity at the time. We are testing the approach on samples from White Sands, NM, but its ultimate application will be to understand the very ancient history of weather on Mars.
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