Diversity in the deep sea can be amazing. In just this image, there is a glass sponge with zooanthids, octocorals, hydroids, sponges, a crinoid, brittle stars, and all the cryptofauna that we can’t see living in the rubble! Click image for credit and larger view.
Dive 16: Many Mounds Shallow
The final dive of the 2014 Gulf of Mexico Expedition took place north of Dive 15, in a similar water depth range and investigated deep-sea coral habitat on a second set of bioherms. The dive began at a depth of 533 meters on a sedimented seafloor with coral rubble. On the bioherm east of the second waypoint, a straight seafloor scar up the side of a small mound was clearly man-made; this scar dredged up coral rubble from the subsurface. While transecting the mounds, there was 50-100 percent cover of Lophelia pertusa coral rubble (normal on Lophelia bioherms). A few mounds were 100 percent covered in standing dead coral, with 50-70 percent live coral cover in parts (mostly on the peaks). Deep Discoverer passed areas of exposed hard outcrops on the northern sides of mounds between waypoints five and six. This gave way to a more eroded landscape on the next complex mound and fresh fracture faces of underlying carbonate became more common. A prominent submarine dune composed of rippled sediment occurred at a depth of 478 meters. Corals observed throughout the dive included stony corals, octocorals, and black corals. Other fauna observed were sea pens, sponges, shrimp, squat lobsters, crinoids, sea urchins, sea stars, and bat stars, a Darwin’s slime head, goosefish, hake, rockfish, rattails, scorpion fish, tinselfish, roughskin spurdog, a chain dogfish, several black-bellied rosefish, and a number of individuals from the recently discovered family of soft corals, Aquaumbridae. The dive ended on this high at a depth of ~470 meters.
Soft coral in a new, recently described family called Aquaumbridae. The white spots at the base of the polyps are actually coral eggs! Click image for credit and larger view.
Dive 15: Many Mounds Shallow - South
Dive 15 was the first shallow dive along the West Florida Escarpment at a site characterized by a number of bioherms or mounds built by marine invertebrates. A total of three bioherms were investigated during this dive. The vehicles landed at the bottom of the first bioherm at a depth of 577 meters, on sedimented seafloor with some rubble. As the vehicles began to move upslope, the transition from sedimented seafloor to the edge of hard rock was abrupt and coral rubble was everywhere. The second bioherm was characterized by rubble/debris, including coral fragments and 50-70 percent live coral cover in the area. The final bioherm sat atop old carbonate layers, some of which were broken, exposing fresh carbonate characterized by abundant fossil burrow structures. While transecting the mounds/bioherms, there was 50-100 percent cover of Lophelia pertusa coral rubble throughout the dive. Aside from Lophelia, other corals encountered during the dive included bamboo corals, black corals, stoloniferous corals, and a number of other octocorals. Other biota observed during this dive included shrimp, squat lobsters, bobtail squids, crinoids, and sponges (including a recently described new species). Throughout the dive, the Deep Discoverer remotely operated vehicle documented a diversity of fish species- cardinal fish, Darwin’s slime head, goosefish, duckbill eel, hake, rockfish, scorpion fish, rattail, and Atlantic thornyhead. The biological highlight of the dive was documenting live predation on a Primnoidae coral by a sea urchin.
A dandelion, or rare benthic siphonophore, resides under a ledge along the West Florida Escarpment. Click image for credit and larger view.
Dive 14: Many Mounds Deep
Dive 14 was the second dive along the central part of the West Florida Escarpment. Remotely operated vehicle Deep Discoverer (D2) arrived on the seafloor at 2,096 meters on a massive carbonate outcrop covered with soft sediment. The vehicles transited to the inner edge of the bench at 2,082 meters, then began up a steep slope with vertical intervals. This slope was composed of a series of steps formed by massive carbonate layers broken by small benches formed by bedding planes. Debris and soft sediment often accumulated on these benches. The top of the slope occurred at 1,887 meters and the ensuing broad bench was formed for the most part by a series of flat-lying stacked bedding planes. Some were the tops of massive layers, characterized by fossil burrows, algal mats, and drainage channels. At least 23 species of coral were observed, including many recruits, suggesting a healthy ecosystem that is ideal for recruitment. There was also an increase in coral abundance at ~1,970 meters. Rare sightings during this dive included a dandelion (benthic siphonophore), white fan bryozoans, a five-armed crinoid never before seen at this depth in the Gulf of Mexico, and four carnivorous sponges. Other species observed included glass and demosponges, a skate, two species of eels, crinoids, and bat stars. Just before the vehicles left the seafloor, some mollusk casts were seen in a large piece of debris, at 1,827 meters.
A dumbo octopus uses its ear-like fins to propel itself off of the seafloor. Shortly after this octopus left the seafloor, it displayed a never-before-documented body posture. Click image for credit and larger view.
Dive 13: Large Mound Area Deep
Dive 13 scaled the steep slope of a wall along the central part of the West Florida Escarpment in search of deep sea coral habitats. Remotely operated vehicle Deep Discoverer (D2) landed at a depth of 2,187 meters, on a massive carbonate outcrop. The wall alternated between vertical intervals and benches formed by bedding planes. Thicknesses of individual beds varied, from very thin intervals to massive layers. As D2 climbed the slope, there was an abundance of a wide variety of octocorals, including multiple species of bamboo corals, bubblegum corals, and spiral corals as well as black coral, a few other species of soft corals, and one species of stony coral. Glass sponges and crinoids, including two potential new species, were also common in this area. Throughout the dive fish were rare, with only two observed. On the upper parts of the wall, cavernous overhangs became more prominent and a possible collapse structure was observed at 2,109 meters. Debris of various sizes sat on bedding planes throughout the dive. Two highlights of the dive included a slime star and a rare sighting of a dumbo octopus displaying a never-before-seen body posture. The dive ended atop a small high at the top of the slope at 1,962 meters.
View from the bow of NOAA Ship Okeanos Explorer as she transits to the West Florida Escarpment for the second segment of the 2014 Gulf of Mexico Expedition. Click image for credit and larger view.
Always Exploring–everywhere NOAA Ship Okeanos Explorer goes, she collects high-resolution sonar data. Here you can see the multibeam bathymetry data that has been collected so far during the third leg of the 2014 Gulf of Mexico Expedition. Our next set of dives will occur on the West Florida Escarpment (shown here in white dots). We found a lot of interesting things in the Northwestern Gulf, stay tuned to see what we find next! Click image for credit and larger view.
Transiting to the West Florida Escarpment
After yesterday’s dive, the remotely operated vehicle team secured the vehicles and we began our transit to the West Florida Escarpment to commence the next stage of the expedition – exploring deep-water areas on the Central-West Florida Escarpment. During the transit we collected high-resolution sonar data, including multibeam bathymetry, seafloor and water column backscatter, subbottom profiler, and water column data via XBTs. We also deployed three Argo floats during the transit that will spend the next several years collecting constant oceanographic data. Our shore-based teams spent the day preparing for the next set of dives, prepping Exploration Command Centers, and training students in the identification of deep sea fauna.
Here you can see a close up view of one of the “tar lily” “pedals.” The first asphalt extrusion had a number of corals and anemones colonizing it. These organisms allowed our science team to give these features an approximate age on the order of tens to hundreds of years old. Click image for credit and larger view.
Dive 12: Tar Lilies
The primary objective of Dive 12 was to investigate an approximately 60 meter-long sidescan acoustic target, which was suspected to be a shipwreck. The dive was conducted in water depths of 1,925-1,930 meters. The site was approached from the southwest, across a flat, sedimented seafloor characterized by scattered black areas suggestive of bacterial mats and a number of unbranched bamboo corals and holothurians. Sea pens, shrimp, and polychaetes were also present in this area. A wooden log was found, heavily infested with squat lobsters. Within minutes of observing the first part of the suspected shipwreck, it became clear that the feature was not man-made, but a natural phenomenon that was nicknamed a “tar lily.” Discussion between the shore and the ship zeroed-in on the likeliest explanation – that this feature was a flower-like extrusion of asphalt at the seafloor – the first of its kind documented in this area of the Gulf of Mexico. Each “petal” of the tar extrusion or “flower” was curved and had internal layering, a result of de-volatilization of the asphalt rising from the sub-seafloor upon its contact with seawater. The first “tar lily” was colonized by fly trap anemones, unidentified sponges, goose neck barnacles, octocorals, sea pens, squat lobsters, and bamboo corals. There were also a few chemosynthetic fauna, including tube worms, bacterial mats, and Alvinocaris shrimp. At the second “tar lily,” there were more chemosynthetic worms, a spiral coral, a few octocorals, and several branching bamboo corals. On both structures, there was evidence for the presence of hydrate from seafloor staining near the base of asphalt extrusions. However, no bubbles of either gas or oil were observed escaping from either structure.
The documentation of this colony of bamboo coral at a depth of 2,834 meters possibly extended the depth range of these types corals in the Gulf of Mexico by several hundred meters. Click image for credit and larger view.
Dive 11: Sigsbee Escarpment
Dive 11 explored the Sigsbee Escarpment, starting on a sediment-covered seafloor at a depth of 2,867 meters. As Deep Discoverer moved up the slope, the seafloor became stepped, characterized by flat-lying outcrops/ridges of layered sediments exposed at the seafloor. The stepped nature of the slope persisted throughout the dive. Several species of octocorals were noted on layered outcrops at approximately 2,830 meters, including bubblegum coral and bamboo corals, possibly extending the known depth range for these types of corals in the Gulf of Mexico by 300-400 meters. Also present were a number of elephant ear sponges, anemones, glass sponges, tube worms, rattail fish, one halosaur, sea stars, and squat lobsters. Prominent furrows oriented diagonally downslope began to appear at 2,777 meters. These furrows/rills persisted upslope almost to the end of the dive. Near the end of the dive, extensive outcrops of sandstone/siltstone occurred, along with complex downslope drainage channels of various sizes. The vehicles were recovered from a depth of 2,723 meters.
An unidentified jellyfish (possibly Narcomedusae?) with bent tentacles was sighted during the pelagic transects. Click image for credit and larger view.
Dive 10: Mid-water Transects, Bryant Canyon
Dive 10 started with five 15-minute mid-water transects occurring in 100-meter intervals between 800 and 1,200 meters to examine pelagic fauna. Sighted during the transects were: shrimp, salps, ctenophores, bristle mouth fish, siphonophores, chaetognaths, “sinkers” (remnant mucus feeding sacks from larvaceans), hatchet fish, a sea butterfly (i.e. Pteropods- the animals who’s shells are seen on the sediment during most of the dives), and a few different types of jellyfish.
The second portion of the dive conducted a transect up the western wall of Bryant Canyon, starting from a depth of 2,813 meters on sediment-covered seafloor. Biota in the area included a few sea cucumbers, glass sponges, fish, sea stars, shrimp, anemones, sea pens, and a few snail fish. The first extensive hardground outcrops began at a depth of 2,765 meters. Furrows, similar to those found on Dive 9 on the other side of Bryant Canyon, were observed at 2,584 meters. In this area, Deep Discoverer (D2) encountered human debris, anemones, glass sponges, tunicates, cusk eels, tripod fish, and squat lobsters. More extensive hardgrounds were observed beginning at a depth of 2,531 meters. Sea stars, glass sponges, and sea cucumbers were common throughout the rest of the dive and flytrap anemones were common on steep slopes. Hardgrounds and layered outcrops persisted, with occasional near-vertical slopes, until the top of the slope, near the end of the dive. Although mostly barren, D2 documented one crinoid, a few glass sponges, sea stars, squat lobsters, polychaetes, sea pens, shrimp, and tripod fish. Rippled seafloor also occurred intermittently near the top of the slope. The dive ended at a depth of 2,470 meters.
ROV Deep Discoverer explores the interesting geomorphology of Bryant Canyon. Click image for credit and larger view.
Dive 09: Bryant Canyon
Dive 09 was the first of two dives along the flanks of Bryant Canyon and examined a ridge along the “shallow” eastern flank of the canyon. Remotely operated vehicle Deep Discoverer (D2) began the dive on a gentle slope of soft, unrippled sediment in 2,593 meters of water. Very small hardground pieces were occasionally observed, generally hosting anemones. Throughout the dive, we encountered sea cucumbers, tripod fish, anemones, glass sponges, sea stars, and shrimp. On the initial slope, there was a small patch of rubble colonized by sea stars, swimming sea cucumbers, and a glass sponge. Rare species included a small hermit crab carrying two anemones on its shell, a lizard fish, and six unidentified anemones on human debris. As D2 climbed the slope, the bottom soon became characterized by parallel gullies/rills/mega-furrows. These drainage features were generally three to five meters wide and one to two meters deep. Floors of these downslope features were often wide and flat, but also complexly configured with internal meandering bars and drainage divides. The furrowed area was mostly barren, but with some tube polychaetes, shrimp, sea cucumbers, and glass sponges. Towards the end of the dive, on occasionally rippled seafloor, there were three species of unidentified anemones on small rocks, as well as a sea cucumber and sea star. During the dive, D2 encountered circular depressions in seafloor sediment. Although our science team has a number of hypotheses about could cause these depressions, there is still further exploration to be done. The dive ended at a water depth of 2,396 meters.
Over the last few dives, sea cucumbers have been one of the most abundant species we have seen. This guy was spotted meandering across the soft sediment during dive 08. Click image for credit and larger view.
Dive 08: Keathley Canyon
Dive 08 conducted a 2.4 kilometer transect in Keathley Canyon. The bottom was 100 percent sediment throughout the dive with either rippled or flat sediment. There were many unidentified shrimp, glass tube sponges, swimming sea cucumbers, and spoon worm feeding marks. In addition, brittle stars, Bathysaurus (lizardfish), sea stars, anemones, two types of tripod fish, polychaete tube worms, and a stalked crinoid were all observed. En route to waypoint four, stalked glass sponges were seen both alive and dead in association with flytrap anemones, along with burrows laid in a circle (possibly created by armored shrimp). Towards the end of the dive, Deep Discoverer encountered a paper nautilus shell. At the very end of dive there was a small rock outcrop which was home to one Paramuricea octocoral with associated goose neck barnacles. There were also two species of squat lobsters and several different types of glass sponges present.
Monterrey Shipwreck B is different than Monterrey A and C. It contains a great deal of organic material and the hull is not copper sheathed like the other two. Monterrey B likely represents a merchant vessel dating to the early 19th century and carried a cargo of animal hides and large white blocks. The composition of these blocks is unknown, but they may be tallow rendered from animal fat. This photo shows several rolls of hides and a white block in the far left foreground. Several unopened wooden crates remain intact and the ship's stove is in the background. Click image for credit and larger view.
Dive 07: Monterrey Shipwreck B
Dive 07, our second archaeology dive, explored Monterrey Shipwreck B, a small wooden vessel from the early 19th century in roughly 1,300 meters of water. Though the smallest of the three Monterrey shipwrecks, Monterrey B may prove to be one of the most interesting and important archaeological and archaeo-biological discoveries in the Gulf of Mexico. The dive began with a slow transit starting at the stern, moving along the starboard side to the bow, and then back to the stern along the port side. All visible artifacts were carefully inspected and recorded and the associated colonizing organisms identified or described. Artifacts and features of particular interest include: an iron gudgeon and pintle; a cast iron ship’s stove; two cántaros (water storage jars from Yucatán); large glass bottles; ceramic tableware; navigational instruments; bales and stacks of hides; large white blocks (hypothesized to potentially be tallow, copal, or rubber); and intact wooden boxes, which may still contain their original contents. Biological observations on and near Monterrey B include: sea cucumbers, crustaceans (including shrimp, squat lobsters, and crabs), corals, tubeworms, isopods, polychaetes, anemones, ship worms, clams, eels, sea spiders, bivalves, brittle stars, spoon worms, limpets, and bacterial mats.
Dipping layered consolidated sedimentary block partially buried in soft sediment on the upper slope surveyed during this dive. These blocks, most buried by soft sediment, formed a hummocky seafloor topography that suggests: 1) that these sub-seafloor sediments have been pushed upwards by rising deeper salt/evaporites and/or 2) that gravity has caused slumps/submarine landslides on this ~7-8 degree slope. Click image for credit and larger view.
Dive 06: Keathley Canyon
Dive 06 was our second dive in Keathley Canyon, approximately 20 kilometers south of Dive 04, and began at a depth of 2,130 meters. The initial view of the seafloor showed unconsolidated sediment, with pronounced ripples. During our first transit, Deep Discoverer (D2) captured some fantastic imagery of several sea cucumbers swimming and eating, as well as a deep-sea lizardfish and a number of shrimp. Heading to Waypoint 2, we saw a number of cerianthid anemones and a thread leg shrimp. A few swimming polychaetes, liparid fish, and cutthroat eels were sighted and tripod fish were common. Sediment cover featured mostly pteropod shells with little to no ripples; on hard bottom, there were a few small white sponges and fly-trap anemones. Throughout the transit, we also saw several single stalked bamboo corals, the only species of coral on this dive. As the dive progressed, there was an increase in hummocky seafloor with associated hard ground and layered outcrops of more consolidated material. Individual hummocks were often a meter or more in height. Burrows in these outcrops were common. Biota in this area included sea cucumbers, cutthroat eels, rattail fish, shrimp, and several glass wedding sponges. Towards the end of the dive, D2 came across a set of Paleodictyon holes, one of the highlights of the day. Virtually identical, enigmatic “trace” marks have been seen in the geologic record for some 600 million years, and their cause is still being debated.
ROV Deep Discoverer (D2) visited three historic shipwrecks during the 2014 Gulf of Mexico Expedition. Here, D2 investigates Monterrey Shipwreck C’s anchor and the associated fauna and artifacts in the area. Click image for credit and larger view.
Dive 05: Monterrey Shipwrecks C and A
The main objective of Dive 05 was to investigate two shipwrecks located several miles apart in roughly 1,300 meters of water. The dive began on Monterrey C where remotely operated vehicle Deep Discoverer (D2) spent the majority of time making biological observations, documenting artifacts, and gathering information that will help marine biologists and archaeologists understand the natural processes shipwrecks undergo in the deep ocean. Monterrey C is the remains of a copper sheathed, wooden hull/copper fastened sailing vessel, approximately 100 feet long. Damage at the stern along with the concentration of artifacts and ballast in this area suggests the vessel struck the bottom hard by the stern and rolled to the port side. Artifacts located in the stern include octants, a compass, a possible chronometer, sounding leads, glass liquor bottles, ceramic bottles, jugs, and plates. Inside the hull amidship is a very large anchor and next to it is the remains of a capstan. The bow contains two largely buried anchors and two lead hawse pipes. Biological observations on Monterrey C included coral, anemones, crustaceans (including squat lobsters and an Agassiz King Crab), tubeworms, isopods, and sponges.
Following completion of work on Monterrey C, Okeanos Explorer towed D2 underwater to Monterrey A. The objective of this visit was to observe the wood experiments deployed by Exploration Vessel Nautilus in 2013 and make further observations on biology and artifacts. The wood experiments represent the types of wood used in 19th century ship construction which our science team will use to learn about the degradation of shipwrecks in the deep ocean. The organisms observed on or near the experiments included fish, squat lobsters, isopods, limpets, tubeworms, and gastropods. D2’s transit around the perimeter of the site provided detailed observations of the pivot gun, gun carriage, and other artifacts. Other biological observations on Monterrey A included polychaetes, ship worms, coral, anemones, crabs, tubeworms, squat lobsters, and hydroids.
This rare yellow ctenophore caused quite a stir amongst our science team as it drifted into remotely operated vehicle Deep Discoverer’s field of view. It was later identified as Lampocteis cruentiventer, a ctenophore that comes in a variety of body colors and pigments but all have a blood red gut. Click image for credit and larger view.
Dive 04: Keathley Canyon
Dive 4 conducted a transect from the main channel of Keathley Canyon up the western wall, starting from a depth of 2,000 meters and ending at approximately 1,760 meteres. The main channel was characterized by soft, unconsolidated sediment with a down-canyon current of approximately one knot. Biota in this area was rare, but included sea cucumbers, sea stars, a few thread shrimp, a Liparid (snail fish), and several halosaurs (lizardfish). Deep Discoverer (D2) next transited up the canyon’s lower west-facing wall, which was composed of slightly consolidated sediment. Sparse fauna along this wall included more sea stars and two clusters of parchment worms. After the lower wall, D2 moved across a flat area before reaching a second, steeper wall. Numerous slump scars were visible, as were numerous meandering gullies that suggested brine seeps. However, no such seeps were encountered. While transiting up this slope, D2 encountered several octocorals, crinoids, fly trap anemones, and sponges. There were also sea pens, an egg mass, and squat lobsters. The upper part of this wall appeared unstable (possibly from brine seepage) and had evidence of landslides. Crinoids were abundant, as well as living bamboo corals and anemones. We also encountered a bubblegum coral towards the end of the dive.
Mapping operations were conducted today following cancellation of the remotely operated vehicle dive due to heavy seas. Here, Mapping Team Lead Meme Lobecker conducts an XBT, or expendably bathythermograph cast, to measure temperature down to 760 meters in order to correct mapping data for water column variability. Due to the high sea state and heavy winds, she is accompanied by a team member (Expedition Coordinator, Kelley Elliott) to ensure safe operations. They are watching the incredibly thin copper wire as it pays out from the XBT to ensure it doesn’t contact the ship and corrupt the data. Click image for credit and larger view.
Rough Seas: Dive Postponed, Mapping Continues
Today’s dive was postponed because of high seas making conditions unsafe to deploy and recover the remotely operated vehicle (ROV). Always prepared for contingencies, our mapping team developed a plan and spent much of the day acquiring new high-resolution sonar data that will be made publicly available as soon as possible after the cruise. Other onboard personnel used the day to troubleshoot recent technical issues, plan and adjust future operations, catch up on work, and get some rest. Expedition team members both at sea and onshore are keeping an eye on the forecast and crossing our fingers that conditions tomorrow will be safe for conducting ROV operations.
Dive 03: Assessing Mid-water Coral Habitats
The third dive concentrated on assessing mid-water coral habitats by examining first the ~ 30-degree slope then part of the crest of an approximately 100-meter high topographic high (part of a sinuous ridge) in depths of ~1,150-1,050 meters. This dive represented the first of multiple dives designed to quantify models of deep-water coral habitats in the Gulf of Mexico. The dive began on flat sedimented seafloor at ~1,152 meters. Most of the dive involved moving slowly up a steep slope featuring scattered carbonate hardground outcrops of varying size. Many of the larger outcrops were encrusted with solitary corals and associates. Generally disarticulated bivalve shells were ubiquitous, suggesting the proximity of chemosynthetic communities. Some of the hardgrounds were also composed of cemented bivalve shells. Occasional concentrations of live mussels and clams and bacterial mats were encountered, but escaping bubbles were observed only once. The steepness of the slope led to substantial visual evidence of downslope movement of sediment, evidenced by slide scars. In several instances, light colored outcrops were exposed in these scars that looked like hydrate, but that could not be confirmed. Corals attached to hardground outcrops became more common at the edge of and across the crest of the topographic high at ~1,052 meters. The top of the high was generally characterized by a pronounced hummocky topography; some of the depressions were several meters deep. Such topography is suggestive of collapse, the result of dissolution of upwardly mobile evaporites at the seafloor. The dive ended about an hour early as a result of failure of the bow thruster, due to overheating associated with seaweed clogging the thruster well.
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. Click image for credit and larger view.
Dive 02 – GB907
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.
Towards the end of the first dive, we found a carbonate outcrop inhabited with the chemosynthtic mussel Bathymodiolus sp. These mussels appeared to be encased in methane hydrate, formed by methane gas conglomerating at their base. Click image for credit and larger view.
Dive 01 – GB648
NOAA Ship Okeanos Explorer had a great first remotely operated vehicle (ROV) dive today to kick off the 2014 Gulf of Mexico Expedition. ROV Deep Discoverer (D2) was launched to a depth of 962 meters at site GB648, now known to be a site of active hydrocarbon seepage. Shortly after reaching the bottom, D2 came across a potential extinct mud volcano. This carbonate structure was covered by encrusting sponges and bacterial mats and surrounded by dead mussel shells. As the dive proceeded, we came across several carbonate structures with apparent hydrocarbon seepage. Most notable was what our science team called the “Amphitheater of Chemosynthetic Life” – a large carbonate ledge covered in chemosynthetic mussels with methane hydrate underneath. Mussels were growing on top of the ledge, under the ledge, and upside down on the “roof” of the feature. Other fauna in the area included ice worms, sea urchins, fish, crabs, and starfish. Small white gastropods (snails) were common close to active seep sites, likely feeding on the chemosynthetic bacteria. Many bacterial mats were seen in a range of colors (white, orange, and black) and always associated with seeps. Corals were rare and low in diversity throughout the area. Other dive highlights included a hydrate tube that had a stream of both oil and gas bubbles, rapid hydrate formation around methane gas bubbles (similar to a rind of ice), and a large structure covered in mussels in the proximity of several bubble streams. During this dive, D2 also successfully tested two new pieces of equipment—a temperature probe and downward-looking mosaicking camera.
During remotely operated vehicle expeditions, the science team uses Fledermaus, a 3D visualization software, to view sonar data to help plan the upcoming dives. Our onboard science team displays the latest datasets collected by the ship and streams the computer display to shore as a live video feed so the entire team, regardless of location, can view the same computer display and engage in dive planning discussions. The image above displays the seafloor backscatter data at site GB648, which tells us the relative hardness of different areas of the seafloor (lighter areas are harder and likely carbonate material, and darker areas are softer and likely soft sediment). Orange dots are proposed dive waypoints, and the yellow dots are seafloor locations where our sonar detected possible gas bubble plumes emanating from the seafloor into the water column. Ultimately, the blue line in this image was decided upon by the group as the final dive target. Click image for credit and larger view.
Preparing for the Expedition from Shore
As Okeanos Explorer steams out to the Northwestern Gulf of Mexico and prepares all of the shipboard systems, our shoreside mission team is preparing for the expedition as well. During this expedition, the Okeanos science team will be spread throughout the country as scientists participate from six Exploration Command Centers (Stennis Space Center, MS; Silver Spring, MD; Harbor Branch Oceanographic Institution, FL; Texas A&M University Galveston, TX; Meadows Center, TX; and the Inner Space Center, RI) or their offices, labs, or homes. More than 70 scientists and students have expressed interest in joining the expedition from shore! A large, distributed science party means the expedition requires far more coordination than a traditional cruise with only an onboard team. Over the last few days, our team has been testing equipment, staging dry runs of mission activities, providing training to new personnel, and troubleshooting any issues that arise. We have new team members this year and a larger science party than ever before, so our shoreside team has been very busy providing training on the tools and technology that will bring this telepresence-enabled exploration to shore.
The sun sets off the starboard bow of NOAA Ship Okeanos Explorer after she leaves port in Pascagoula, MS, and transits to the western operating area of the expedition. Click image for credit and larger view.
The 2014 Gulf of Mexico Expedition Commences!
NOAA Ship Okeanos Explorer departed Singing River Island, MS, at approximagely 1630 Central today and began transiting to our operating area in the Northwest Gulf of Mexico. We have a full day and half of transit ahead of us and will collect mapping data continuously as we head to our first remotely operated vehicle (ROV) dive site of the cruise. The onboard crew are busy getting familiar with the ship, learning safety procedures and preparing for upcoming operations. Our first ROV dive is planned for Saturday morning, April 12, at a potential gas seep site.
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