Monday, September 16, 2013

Red Mat and Pillars

Weather: Sunset last Sunday night was spectacular (see below). Today the seas have picked up slightly and the skies are overcast.

Science Update:
Today’s Objectives:
1) Complete dive J2-731 and recover ROV Jason on board – check!
2) Retrieve samples, prepare for next dive with a quick turnaround for next dive– check!
3) Launch ROV Jason dive J2-732 – check!

Exploring Red Mat Pillars site
Exploration is one of the great joys of being a field scientist, particularly at sea where sometimes the ocean floor seems like another planet. With only the use of maps and the 10 m illumination distance from the lights of a submersible like the ROV Jason, work here at Axial Seamount is surrounded by a shroud of darkness. We often wonder what lies beyond the lights, and with sonar mapping, we have an excellent idea of the topography and landforms in and around the caldera, but with tight research budgets, roaming around to investigating is not generally an option.

Map inside Axial Caldera showing 2011 lava flows (in black outline) adjacent to east wall of caldera (warmer colors). Note fine detail of topography from the 1 m resolution mapping by MBARI.

Lava flows of 2011 eruption of the Red Mat Pillars area.
On Friday September 13, an opportunity to do some exploration presented itself, partly on the advice of another ocean scientist, and partly to take a chance on a potentially interesting microbiological site. Following the 2011 eruption, a group led by Dr. David Clague from the Monterey Bay Aquarium Research Institute (MBARI) used a multi-beam sonar on the autonomous underwater vehicle (AUV) “D. Allen B.” to map the seafloor in the areas of the new lavas at 1-m resolution. Because they had previously mapped the entire summit of Axial Seamount with the same system, a comparison of the pre-eruption survey to the post-eruption survey revealed the depth changes caused by the new lava flows in unprecedented detail. Then during an ROV expedition a month ago, the MBARI group noted an area on the 2011 flows with a very unusual red mat that they recommended we investigate further.

This kind of reconnaissance had the science team excited to visit and collect samples in an unexplored area and is one of the foundations of our love for our work. “The site is between two other sites on the circuit of our pressure dive so it was easy to go there on our last lap of the dive,” said Chief Scientist, Bill Chadwick. The team called the site “Red Mat Pillars”, because the red mat is in an area where the lava flow drained, collapsed, and left a weird landscape of lava pillars and arches. 

Syringe sampler collecting red material at Red Mat Area.

The unusual appearance of the red mat brought many visitors to the Jason control van and to the monitors throughout the ship. The landforms and biota did not disappoint (photo left and video below). Lavas pillars form as the result of sheets of lava filling a low area, being inflated by the addition of molten lava beneath the original lava roof followed by the molten material draining away in a rapid, but iterative process, leaving “strand lines” similar to bathtub rings on the pillars within the flows. Sometime during this process, the flows have been covered with spectacular colors of what is thought to be microbial mats.

Oliver Vining with the sample on ROV Jason’s return to the surface

Oliver Vining and his advisor Dr. Kerry McPhail at Oregon State University’s College of Pharmacy (see blog: Biomedical Research at the Volcano) aren’t sure about the origin of the red mat (is it biological or mineral?), but Oliver collected three samples and is storing them in the ship’s freezer until he can take them back to the OSU lab for analysis To learn more about the Red Mat Area and hear thoughts on the geology and microbiology of this dive, check out the video below.