West Coast Expedition
July 20 - August 30, 2002
West Coast of North America
August 22, 2002: Day #34
Debra Stakes writes: Today’s dive focused on instrument deployments and geology in the Main Endeavour hydrothermal field of the Juan de Fuca Ridge. This would be our second dive in the Main Endeavour Field and would require the ROV and elevators to transport three separate sensors and their attached data-loggers safely to and from the seafloor. The data collected by these sensors is diverse, and is representative of the types of continuous, long-term environmental measurements required to constrain episodic seafloor processes. In-situ sensor packages included a flow meter, temperature-resistivity probe and microbial incubator. One of the goals of the Keck-supported effort is to develop new sensors and new installation methods to enable continuous measurements to be made over months or years.
Two of the sensor packages were carried down on the ROV itself, and deployed. After Wednesday’s dive, the coring sled was replaced by the benthic toolsled that includes a drawer to hold both samples and instruments. The benthic toolsled also has an expansive front porch where bulky items can be secured for transit through the water column. The first instrument carried down on the front porch and deployed by the ROV was a prototype flow meter for diffusive flow sites such as patches of chemosynthetic tubeworms. The flow meter itself stands upright and is attached by a short cable to the cylindrical datalogger (Fig. 1). The vehicle also carried down a prototype borehole incubator that will be placed into a hole drilled into the black smoker known as "Smoke and Mirrors" (Fig. 2)
The third sensor was carried down on the elevator with a biobox for collecting samples (Fig. 3). This elevator was then carried by the ROV to Smoke and Mirrors to deploy the sensor and collect tubeworms from near the top of the edifice (Figs 4 and 5). The dive was completed with a geological sampling traverse across the center of the axial valley (Fig. 7).