ROPOS uses both it's arms (5-function on the left and 7-function on the right) to collect samples for the many scientists on board the Ron Brown. Attached to the left arm is the suction sampler, while the right hand is used to grab a sample of tube worms at Cloud vent (1524 meters). The hot fluid sampler is pictured in the upper foreground sampling the underside of a pillow lava coated with bacterial mat at marker N-3 (1528 meters). The chemists and microbiologists are collecting water samples and also getting in-situ measurements of pH and sulfides from the vent fluids.

NOAA Ship Ron Brown/ROV ROPOS
Science News

Science Report - Friday, July 20, 2001
Ship's position: 45 54.9/-129 59.4'

ROPOS is in the middle of another long dive (623) which is visiting sites both inside and outside the caldera with a pressure sensor. The pressure sensor precisely measures the depth at an array of points on the seafloor to see if the center of the caldera is going up or down (inflating or deflating) relative to a point outside. During the 1998 eruption, the center of the caldera subsided over 3 meters (!) as magma was removed from the magma reservoir beneath the caldera and was intruded into the south rift zone. Between eruptions that magma that was removed must gradually get replenished from Axial's "hot spot" source in the earth's mantle. We are trying to measure if that is going on to see whether or not Axial is already building up to its next eruption. Today's dive also visited the Marker 33/Cloud and Bagcity vent areas on the 1998 lava flow since they were on the way to take additional suction samples, position larval traps and settling arrays, and deploy miniature temperature recorders. Tomorrow's dive will be our first visit to the ASHES vent field this year.