Teacher Logbook - NOAA Ship Ron Brown

The Hot Fluid Sampler (HFS) pumping vent fluids from Marker-33 vent (1524 meters) The fluids will be used to determine the microbiology and chemistry of the vent site.

Jeff Goodrich's Sealog:
July 18, 2001

Yesterday we concluded at south Cleft with a dive to retrieve and deploy HOBOS (hot temperature recorders) at several vents in the Vent1 and Plume venting regions. Both these areas looked like mini-cities with vent skyscrapers scattered throughout. Temperatures at Vent1 in 1994 measured over than 340 C, more than triple the boiling point of water. To insert the HOBOS' long antennae-like thermometers, ROPOS occasionally had to break a small portion off the top of a vent. This released a cloud of billowing smoke composed of metalic sulfides, mostly zinc sulfide. The vents are very crumbly and fall apart easily but grow back over a relatively short period of time.

After a eight hour steam north to Axial Volcano we deployed ROPOS for its 1500 meter descent in the SE portion of the caldera. Axial's caldera is unusual because it's stretched into a horseshoe-shape measuring 8 km x 3 km and is open on the southern side.

The hydro lab is packed today for our fist glimpse at Axial's vents. At Cloud vent Anna Metaxas conveys to Keith Shepherd where she wants to place her larval traps and arrays. Her normally smiling face is now serious. Bob Holland controls ROPOS's robotic arm to pick Anna's larval traps out of a small cage and place
them in the correct locations. Bob is very dexterous with the arm considering that depth perception is difficult when you're viewing the ocean floor through two-dimensional video monitors. Everyone must be patient as simple tasks are time consuming. During one of the placements, the baseball-topped cork comes off and everyone suddenly gets nervous, for there is formaldehyde in the tube. Knocking the tube over could jeopardize Craig Moyer's bacterial trap experiments. After some time Bob recaps the tube and successfully places the trap. A sigh of relief goes around the lab and the relaxed atmosphere returns.

An hour later a short transit brought us to a crack in the basalt called Marker
33. It's easy to see where the fluids rise from the seafloor because all the cracks are covered in a white mass of bacteria, limpets and an occasional tube worm. Dave Butterfield directed the ROPOS pilot to sample the fluids for pH, temperature, hydrogen sulfide and other chemical parameters. Vent fluids flowed out into the water column bathing the bacteria and limpets in chemically rich life-sustaining fluids. This diffuse vent has cooled down from last year a sign that the volcano may be cooling off from the 1998 eruption.

Things are actually getting a little crowded out here at Axial. Off on the horizon lies Oregon State University's ship R/V Wecoma. The scientists aboard are also part of NeMO and are focusing on vent plumes in the water column. They are conducting CTD (conductivity, temperature, density) casts and deploying moorings, which analyze currents, particulates and temperature.