December 12, 2008
First major experiment installed on MARS ocean observatory
On December 9, 2008, a team of MBARI researchers installed the first major science experiment on the new MARS ocean observatory, almost 900 meters below the surface of Monterey Bay. This project, known as the Free-Ocean Carbon Enrichment (FOCE) experiment, will help researchers study the effects of ocean acidification on marine organisms (The world’s oceans are becoming more acidic as more and more human-generated carbon dioxide (CO2) dissolves from the atmosphere into the ocean.)
The FOCE experiment consists of a 10-meter-long rectangular flume containing a series of baffles. CO2-enriched seawater is released at one end of the flume, then mixes and reacts with the surrounding seawater as it flows slowly around the baffles. In the middle of the flume is a test area, where a one-meter square of seafloor is exposed to consistently elevated concentrations of CO2.
The following photographs document the December 9 deployment of the FOCE experiment. Many of hese images were taken by a video camera on board MBARI’s remotely operated vehicle (ROV) Ventana, which performed all of the underwater work. As usual, Ventana‘s pilots did an amazing job, completing this complicated underwater construction project in a single day.
Crew members of MBARI’s research vessel Point Lobos lower the FOCE flume into the open ocean off of Monterey Bay. The first challenge of the FOCE deployment was to lower this unwieldy apparatus over the side of the ship and down to the seafloor almost a kilometer below. With amazing accuracy, the ship’s crew delivered the flume safely to the ocean bottom within about 70 meters of the main MARS node.
The FOCE flume is so large that it had to be built in three sections, which are connected by hinges. Before the experiment could be loaded on board the Point Lobos, the two end sections were folded up over the central section to form a triangle, as shown in the photo above, taken by the video camera on ROV Ventana.
After the flume was lowered to the seafloor, MBARI’s remotely operated vehicle (ROV) Ventana was sent down to set up the FOCE experiment. Researchers used the ROV’s video cameras to inspect the flume, then used the ROV to pick up and move the flume closer to the MARS node. After setting down the flume about 20 meters from the MARS node, ROV Ventana released a latch that allowed the frame to unfold underwater.
The next step was for ROV Ventana to carry an extension cable from the FOCE experiment to the main MARS node. This cable contains both copper wire (which carries electical power for the experiment) and optical fibers (which carry data, allowing researchers to communicate with their instruments). Within minutes of connecting the cable to the MARS node, the researchers were able to get data from instruments attached to the flume.
In this photo of the fully-extended flume, you can see a number of white blocks. These are floatation devices that make the flume easier to move underwater.
This photo shows another view of the FOCE flume. A cylindrical metal pressure housing (center) protects electronics that are used to control the FOCE experiment. The orange extension cord at lower left connects the experiment to the main MARS node. On December 10 and 11, 2008, ROV Ventana made two additional dives to the FOCE experiment. During these dives, the researchers began injecting CO2-enriched seawater into the flume to test their instruments. Over the next few months, the research team will continue to test their instruments and equipment to find out how well they survive in the harsh environment of the deep sea. Future deployments will investigate what effects CO2 enriched seawater may have on populations of seafloor organisms.
For additional information or images relating to this article, please contact: Kim Fulton-Bennett