Lava pillars near the old rumbleometer sight. While gas tight sampling at Vixen anhydrite vent, bubbles began to pour out of the vent orifice.

NOAA Ship Ron Brown/ROV ROPOS
Science News

Science Report - Saturday, July 28, 2001
Bill Chadwick
Ship's position: 45 55.8'/-129 58.6'

Each of the last 2 years, we have been developing and testing a communication system called NeMO Net designed to allow communication between instruments on the seafloor and scientists back on land. In 1999 and 2000, camera images and temperature data were transmitted hourly from a vent site on the seafloor, first with one-way communication and then with two-way capability.

This year, an interactive fluid sampler has been incorporated into the NeMO Net system, which will allow scientists to respond to any interesting events during the next year (an earthquake swarm, for example) by changing the sampling rate (from weekly to hourly, for example). When submarine eruptions happen in the northeast Pacific, it takes at least a week or more to get a ship out to the site to investigate. The goal we are working toward is to be able to have interactive instruments already in place on the seafloor in order to catch the early stages of events during the first days and weeks when conditions are changing most rapidly and dramatically.

After the interactive fluid sampler was lowered from the ship last night, ROPOS carefully positioned it at Cloud vent during dive 630. Additional tasks during the dive included deployment and recovery of bacterial traps and OSMO samplers, detailed measurements at lava pillars to help model their formation, and an additional visit to the newly discovered Casper and Vixen anhydrite chimneys where large bubbles were seen rising from the vents. This is relatively surprising since the ambient pressure at this depth (1538 meters) generally prevents bubbles from forming unless the gas content of the fluid is very high.