A HOBO temperature recorder has just been inserted into a vent at the Vent1 site at the south Cleft segment. The HOBO will record vent fluid temperatures every hour over the next couple of years. Historically, temperatures in excess of 430 degress Celcius have been measured at this vent field. Iron oxides (yellowish-orange) and dying chimneys abound at the Plume vent field on the south Cleft segment of the Juan de Fuca ridge.

NOAA Ship Ron Brown/ROV ROPOS
Science News

Science Report - Tuesday, July 17, 2001
Ship's position: 44 39.0'/-130 22.1'

ROPOS visited the hydrothermal vent sites at south Cleft named Vent1 and Plume today during dive 621. ROPOS redeployed two temperature probes at a spectacular black smoker chimney at Vent1 that is 15 m high and venting fluid at over 300 degrees C. The probes will take hourly temperature measurements over the next year or more to look for correlations with deformation events that may be recorded by the nearby extensometer array. Other temperature probes were recovered and redeployed at Plume. Tonight the RON BROWN heads north to Axial Seamount where the rest of the NeMO 2001 research expedition will be focused. Axial was the site of a volcanic eruption in 1998 which destroyed some hydrothermal vent sites, but also created new ones. We have been returning to the site each year to document the chemical evolution and biological colonization of the new vent sites.