Today was a full day beginning with an early morning ROPOS dive for the second round of engineering tests of L3-MariPro’s OOI primary node, an EM302 survey over the future site of one of these nodes at Hydrate Ridge, and then another ROPOS dive to recover the secondary node test frame that was deployed during the ENLIGHTEN’10 expedition last year. This mock frame was deployed to test the various materials that will be used to construct the secondary nodes. Engineers from University of Washington’s Applied Physics Laboratory will assess how the epoxy coating placed on the frame (white portions) and the galvanized legs withstood the year of being left on the seafloor at Southern Hydrate Ridge.
In addition to recovering the secondary node test frame, we also searched out a methane bubble plume that was seen during the afternoon’s EM302 multibeam survey and was coincident with an eH anomaly during a survey last year with the autonomous underwater vehicle (AUV) Sentry. Unfortunately, we were unable to visually locate the source of the plume. We moved on to take five push-core samples for Evan Solomon to investigate the sediment porosity at the site of his instrument deployments.
Tomorrow we will be launching the ROV at 10:00 to obtain detailed imagery of the sites where instruments will be deployed on the OOI cabled observatory.