Saturday, September 7, 2013


The clouds are gone and today is sunny and warm (upper 60’s)! The seas are much calmer, nearly no rolling motion (or are we just getting used to the constant ship motion?!)  
Science Update:  
Today’s Objectives:
1) Finished installing the geothermal vent cap experiment with Jason at Vixen vent in the Coquille vent field- check!
2) Retrieve Jason from dive J2-727 - check!
3) Deck operations:
  • Deploy over the side of the ship 2 benchmarks (for upcoming pressure dive) 
  • Deploy RAS (Remote Access Sampler to collect weekly water samples for the next year) 
  • Deploy SCPR (Self-calibrating Pressure Recorder) - an experimental, high precision pressure instrument 
4) Launch ROV Jason on dive J2-728 for next dive at International District Hydrothermal Vent Field - check!

Medea (L) strapped securely aboard R/V Thompson. Note black thrusters on each end of the vehicle and Jason in the background at right.
According to Greek mythology, Jason met Medea while on his quest with the Argonauts to retrieve the Golden Fleece in order to regain his rightful place as king. Medea fell in love with Jason and promised to help him in performing three challenges thought to be impossible, but that would win him the Golden Fleece, and thus the throne. Medea and Jason worked together to successfully complete each task (with some sorcery along the way) and Jason was able to take the fleece, and returned home to be king.

 The WHOI Medea-Jason ROV (see images above left and below right) is used by research scientists to complete a variety of tasks during each dive, all in the pursuit of the “Golden Fleece” of better understanding Earth’s oceanographic processes.
ROV Jason being deployed for dive J2-726 on Sept 6, 2013.
What may seem like a mundane task like collecting water samples or taking the temperature of a hydrothermal vent is actually an expertly choreographed combined effort of the ROV Jason-Medea team, along with the research scientists and ship’s crew.

 At Axial Seamount most of our dives descend to about 1500 m below the ocean’s surface, where Jason and Medea work at a variety of science and engineering tasks. When deployed, the R/V Thompson lowers Medea on a cable to about 30 meters above the seafloor, and Jason is connected to Medea by a tether that is 60 meters long. This arrangement allows the ship’s up and down motion on the ocean’s surface (which causes Medea to move up and down as well) to be decoupled from Jason, so it can work safely and efficiently on the seafloor with Medea looking down from above. This allows Jason to perform delicate maneuvers like installing high precision instruments without being affected by the ships movement on the surface. Jason and Medea are operated in the control van on the ship by a pilot, an engineer, and a navigator (see image below left).

JASON control van onboard R/V Thompson. Medea engineer is at far left, Jason pilot sits in the middle-front, and the Jason navigator is at the far front panel. Science watch leader is in 2nd row at far end.
Images from 7 different cameras on Jason and two on Medea are transmitted to the ship where Jason team members and science crew can see them in the Jason control van (see image left). The Jason van is kept dark to preserve the “night vision” that enhances the crew’s ability to see details of the seafloor through the ROV video on the monitors.

Throughout the dive, a variety of information is recorded, including video and written logs that document the details of each sample or measurement taken, instrument installed, or other activities during the dive (see photo at below right).
JASON control van onboard R/V Thompson. Medea engineer is at far left, Jason pilot sits in the middle-front, and the Jason navigator is at the far front panel. Science watch leader is in 2nd row at far end..

Dives often go through the night (and the upcoming Pressure Dive will go for 5 ½ days non-stop!) so “watches” are scheduled around the clock for the scientific and Jason teams. Shifts of at least three scientists working in the Jason van rotate with watches of 4 hours “on” followed by 8 hours “off” (used for working on other tasks or for sleep). An example shift is “on van duty” from midnight to 4 AM, off from 4 AM to noon, back on watch from noon to 4 PM, and then off again until midnight.

Elsewhere on the R/V Thompson, work continues in the ship’s science labs. Samples from the previous dive are logged and processed, and preparations for upcoming dives are made. But everyone likes to watch the progress of each dive so large monitors are installed around the ship (below).