During the exploration of GB907, ROV Deep Discoverer imaged a group of chemosynthetic mussels and a few sea urchins residing next to a natural oil seep. Here you can see three active oil streams and several oil droplets caught in mucus of the mussels or a neighboring organism. Image courtesy of NOAA Okeanos Explorer Program, Gulf of Mexico 2014 Expedition. Download larger version (jpg, 1.8 MB).
Okeanos Explorer EX1402L3
Dive 02 – Site GB907. Video courtesy of NOAA Office of Ocean Exploration and Research. Download (mp4, 38.0 MB)
Dive 02 was conducted at site GB907 to depth of 1,260 meters with the purpose of investigating a number of targets (potential hard bottom and cold seeps) identified by sonar surveys and conducting a baseline characterization of the biology and geology in the region. As remotely operated vehicle (ROV) Deep Discoverer (D2) transited to the first waypoint, we came across a number of bacterial mats and several sea cucumbers on soft sediment. Our first major discovery of the dive was a large brine pool with a number of islands surrounded by carbonate outcrops. Around the shores of the brine pool we found anemones, fish, corals, sea stars, crustaceans, and tube worms. There were also several living tubeworms sticking through the surface of the brine. As these organisms could not have gotten started in that location, their existence suggests only intermittent existence of the brine pool. D2 left the brine pool and came across areas with bacterial staining and a few carbonate hardgrounds with several small crustaceans and anemones. At one of the outcrops, multiple streams of escaping oil droplets and gas were observed emanating from a living mussel bed. Other fauna in this area included tubeworms, crustaceans, chiton, brittle stars, urchins, and small amphipods. Corals were rare and found on scattered carbonate outcrops. As D2 transited to waypoint 2, we came across a number of scattered carbonate outcrops that were surrounded by chemosynthetic mussels and tube worms. The dive was aborted early due to technical issues on the ship. As we were leaving the seafloor, we noted a large area of mussels with visible gas seepage that we were unable to investigate.