May 15–June 3, 2005
Please visit the Ridge 2000 website for additional information.
May 28, 2005
We moved to the White Lady collecting site, about ~160 km north of Mussel Valley. Ironically, we found no mussels in Mussel Valley but collected quite a few at the new locality. Once on board the Melville, the mussels are opened and tissue is taken from the abductor muscle, which opens and closes the two shells. This tissue is put into a small, labeled, plastic vial and the cap is snapped shut. The label gives the dive number (149th dive of Jason II), sample number (7) and tissue type (abductor). The samples are then frozen for future analysis.
Gray slimy gill material the size of a pencil eraser is put into another labeled vial. The gills have symbiotic bacteria, which interests researchers. The vial with gill sample is flooded with alcohol to preserve the tissue for future DNA analysis, and then stored. These processes will be repeated a hundred or more times, before this expedition is completed. Large numbers of organisms are needed to provide researchers with enough data to make their population genetic research statistically valid.
The population genetic studies are aimed at comparing hydrothermal vent animals from different ocean basins. Movements of the earth's crust over long periods of time form these vast basins. The crust is a dynamic, moving, grinding layer of rock that floats upon the hot, relatively liquid mantle. The seafloor portion of the crust is composed primarily of dark, dense rocks called basalt. The continents are made primarily of lighter rocks knows as granite. The continental rock is less dense than the basaltic rock so it "floats" like foam on water and provides a wonderful platform for terrestrial life.
There are regions under the ocean where molten rock upwells or is forced up from the mantle. This is the origin of the seafloor plates. As the molten rock erupts along these cracks, it cools rapidly forming new sea bottom. Intense forces from within the mantle cause this new seafloor to spread outward perpendicular to these spreading zones in ways still not universally understood. Seafloor spreading is the engine that drives plate tectonics hence, continental drift.
The White Lady area is one where three crustal plates merge, known as a triple junction. This dynamic area hosts some wonderful thermal vents. These vents then support the various life forms, which have attracted the attention of the world class scientific team aboard.
This expedition has been made possible by National Science Foundation grants to Dr. Robert Vrijenhoek (NSF OCE-0241613) and Dr. Cindy Van Dover (NSF OCE-0350554)