Daily Science Report: Friday February 10th

By Mike Cheadle

Hydrothermal vent day at Pito Seamount! We launched Jason on Thursday evening after a quick turnaround with the Jason team going above and beyond to get Jason ready for action. Just after 7pm, we were on the seafloor crossing relatively fresh lava flows- in fact the volcanic landforms were spectacular throughout the dive, which was perhaps not surprising, because Pito Seamount is more East Pacific Rise than seamount. It even has it’s own rift/axial valley. Aided by the bathymetry images and data provided by Sentry together with the expert guidance of the world renowed “ventfinder general”, and on shore scientist, Chris German, we found our first active blacksmoker vents within the first hour and spectacular they were. We named the first two Jason and Medea after the two vehicles/ROV system we are using. Jason vent was large & very “smokey” and the Medea vent was just beautiful. Later ones were named Sentry and ABE. We discovered at least 4 new vents in three separate sites and 10’s of “dead” vents at various stages of decay. Most were of the “live” ones large (the tallest was 22 metres high) and delicate. Polychaete worms, mussels, fish, gastropods, anenomes, and crabs were common at the live vents, but Freyella like brisingid sea stars called the dead vents their home (see adjacent photo). We returned from the seafloor after lunch and later gazed at our samples of chimneys and basalt.