Today we revisited the bubbling methane
vent site we located during our previous leg, known informally as
Pinkie’s Vent. The plan for the day included two dives: the morning dive
for collecting push cores, gas samples, and heat flow measurements; and
the afternoon dive for further work with the laser
the vehicle reached the seafloor, we drove toward the vent site and were
pleased to see our flamingo mascot, Pinkie, standing watch over the vent.
During the last leg, we left Pinkie on the seafloor as a marker of the
area in which we had collected samples. A number of astute budding marine
biologists have written us and have pointed out that flamingos don’t
have gills. You are correct, but Pinkie is special. Not only is she the
only known gilled flamingo in existence, she has a talent for gardening.
You will notice in the upper left-hand corner of the accompanying photo
(see above). Peter
Brewer’s gas hydrate hoe was left behind during our last visit. We
understand from Pinkie that she is experimenting with tomatoes, but the
snails are bad (see below).
recovered the vehicle at noon, and the pilots
quickly reconfigured the hardware for the afternoon dive. During this
dive, the laser Raman probe head was mounted vertically in an aluminum
frame that we planned to place on the seafloor. This rather large frame
was secured to the front of the vehicle—on the “front porch,” as we
like to call it (see right).
The afternoon progressed quickly as we made several attempts to capture either solid hydrate chunks from the seafloor or gas from the vent area. Gas was trapped beneath a gas collection funnel and placed in a slot in the aluminum frame. The laser beam was projected through the sample. When collecting laser Raman spectra, the vehicle lights are turned off to reduce spectral interference. Because only a very small amount (~1%) of the laser light is shifted by the Raman effect, we have to record the light spectrum for 15-20 minutes per experiment (see below). Sheri White was rather pleased to get strong methane signals from the experiments conducted this afternoon.
Trapping gas with the gas collection funnel (above left) to be analyzed using the lasar Raman spectrometer (above right).
The answer to last night’s mystery item: Lynne Christianson, in stylish purple gloves, is holding a sediment squeezer body. This plastic container is filled with sediment extruded from a sediment core, then covered with a thin rubber dental dam, and placed into a clamping jig that allows air pressure to push the water that fills the pore spaces around sediment particles into a collection syringe. This is the way in which we obtain water and dissolved gas samples for chemical analysis in Bill Ussler’s on-board chemistry van.