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Participant Interview:
June-July 2000
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NeMO Date: July 5, 2000
Ship's Location: 45 56.0'N/130 00.8'W

Use the Interview calendar at left for all Participant's perspectives.
 
         
         
 

Participant Interview:
Leigh Evans
Chemist
Oregon State University/NOAA Vents

Jeff: What are you measuring with all your fancy equipment?
Leigh: On board ship I'm measuring the amount of dissolved gas in the vent fluid. On land I'll be measuring helium isotope concentrations. Some of the samples are sent to labs that measure other gasses in vent fluids such as methane, hydrogen, carbon dioxide and hydrogen sulfide.

Jeff: Why are you looking for these particular elements in the vent fluid?
Leigh: Helium is a geochemical indicator of how active a vent is and how it changes over time. The ratio of He3 to heat varies with time duration since a seismic event. We can compare He3 in newly formed vents, such as the 1998 Axial eruption area, with vent fields in that haven't been perturbed by any type of seismic event. Methane, produced geologically or biologically, and hydrogen give some insight into other chemical processes that are occurring in the rocks beneath the sea floor.

Jeff: Isn't helium a good tracer for studying hydrothermal vent plume movement?
Leigh: Yes. We study plume dynamics with some types of helium isotopes. Vents inject enriched He3 into the water column, where it finds its buoyant level, disperses, and is transported with deep ocean currents. In a few cases we think we know where it's going.

Jeff: What gets you excited about your research?
Leigh: It pays most of the bills. Also, I'm not building bombs, which I contributed to during my five years while in the aerospace industry.

Jeff: What kind of societal benefits result from your research?
Leigh: Plume studies are a check against more sophisticated oceanic circulation models. A greater understanding of ocean circulation would contribute to global warming research. It might illuminate questions such as: Where's all the CO2 going in the ocean?

 

Leigh Evans donning a life-vest and hat for the weekly fire drill.

More information on helium research at the Vents Program.