Friday, September 20, 2013

Final Posting

Our September 2013 expedition to Axial Seamount was a great success! We managed to complete all our major goals with the skilled support of the R/V Thompson’s crew, the ROV Jason team, and our hard-working group of scientists. We also had unusually good weather for this part of the world, which always makes everything easier at sea. This research cruise had three main projects.
Science team aboard the R/V Thompson.

One project was to collect fluid and microbial samples from Axial’s hydrothermal vents to better understand the microbial ecosystems that form the base of the food chain at seafloor hot springs. We collected samples of hydrothermal vent fluid to track changes in chemistry since Axial’s 2011 eruption and how those changes may effect the microbial communities that live in the warm chemical-rich waters below the seafloor. We used a range of sophisticated samplers to collect vent fluids, gases, microbial mat, and hydrothermal sediments. We also collected the microbes living in the vent fluids for culturing experiments on board the ship and genetic analysis back on shore.
The intake of the Hydrothermal Fluid and Particle Sampler (HFPS) collects hot shimmering water near Vixen vent (in the Coquille vent field), surrounded by tubeworms, palmworms, and limpets.

The second project was a geothermal energy experiment that deployed prototype instruments on the seafloor to assess the feasibility of converting thermal energy from hydrothermal vents to electrical energy that could be used to power deep-sea sensors or perhaps underwater vehicles in the future. Geothermal energy devices were successfully placed on three separate hydrothermal vents at Axial. They will stay deployed for the next year and continue to collect data until they are recovered next summer. The results from this experiment will guide the design of more advanced energy conversion devices in the future.
Vent cap in place at Vixen vent.

The third project was making seafloor pressure measurements to monitor how much the volcano has reinflated since its last eruption in 2011. This was accomplished during a long Jason dive (almost 5 days) that repeatedly visited 10 different measurement sites, traversing a total of 65 km. These measurements found that the center of Axial’s caldera has risen by 1.2 meters (4 feet) in the last 2 years, the highest rate of uplift we’ve seen since we started these measurements over a decade ago! This means the volcano has already recovered over half of the deflation that occurred during the April 2011 eruption, and suggests that Axial may be closer to its next eruption than we expected. We will need continued monitoring to anticipate Axial’s next move, but these results are exciting and add urgency to the efforts to complete the installation of the cabled observatory at Axial as soon as possible.
Jason’s manipulator arm (upper right) prepares to place a pressure recording instrument (yellow) on a seafloor benchmark (concrete disk, middle) to measure how much the volcano has reinflated since its 2011 eruption.

We are grateful to the funding agencies that supported our research: NOAA’s Pacific Marine Environmental Lab, The Gordon and Betty Moore Foundation, The Office of Naval Research, and The National Science Foundation. We also greatly appreciate the support from the University of Washington (who operates Thompson), the Woods Hole Oceanographic Institution (who operates Jason), and the National Deep Submergence Facility (which manages Jason).

And thanks to you for following along during our research cruise and for all the great questions that we received. We had some fun interactions with students and teachers in science classrooms during the cruise via our satellite-based internet connection. I hope you will be able to join us again on a future expedition to Axial Seamount. I’m already looking forward what we will discover then!

-Bill Chadwick, Oregon State University

Cruise Report:
The cruise report is available as a pdf at:
Report with all dive logs (13MB) or Report without dive logs (5.7MB)

Highlights from the expedition:
(click image for full-size version)

Vent fluid from the top of El Guapo sulfide chimney (in the International District vent field) is collected for chemical analysis. The fluid is as hot as it can be because it is venting at the boiling point for this depth (347°C).
A remote-controlled fluid sampler is deployed at El Gordo vent (in the International District vent field) where it will take one sample per week to monitor the vent fluid chemistry over the next year.
The side of Escargot chimney (in the International District vent field) is covered with blue ciliate mat. The front of Jason’s basket is visible in the foreground, ready for fluid sampling.
Close-up of shiny, black 2011 lava frozen in place after pouring over a ledge.
Glassy black lava from the 2011 eruptions pours over a ledge and partially fills a pre-existing depression near Bag City vent.
Jason’s manipulator arm reaches to sample vent fluids from a vent called Spanish Steps.
Red and yellow stained microbial mat form on the upper collapsed crust of the 2011 lava flow in this area.
A hydrothermal vent community living on the side of a sulfide chimney in the Dependable vent field includes tubeworms, palmworms, limpets, several kinds of scaleworms, and sea-spiders called pycnogonids.
Orange iron-stained bacterial mats and a blue ciliate coat tubeworms growing on the side of a sulfide chimney in the Dependable vent field.
Hot vent fluid pools under an overhang on a sulfide chimney, called a “flange”, in the Dependable vent field.
Two spider crabs feast on a dead jellyfish that has fallen to the seafloor.
A “dumbo” octopus (named for its ear-like fins that it uses to swim) rests on the flat floor of a lava channel in the 2011 lava flows.