In the last couple minutes of the last dive of the field season, we found the largest fish we have ever encountered with the ROV, a Greenland Shark.
Today we had a relatively shallow dive at a landslide debris field between Alvin and Nantucket Canyons. The remotely operated vehicle (ROV) was on bottom, ready to explore, at 1304 UTC at a depth of 896 meters. The dive started along a smooth, sedimented seafloor that transitioned to hummocky terrain. Several burrows of different sizes were observed throughout the dive, some occupied by red crabs and squat lobsters. The first large rock was observed at 885 meters. The landslide debris area was heavily sedimented, possibly an indication that the landslide had occurred long ago in geological time scales. The ROV transited up a sedimented slope throughout the rest of the dive. Once the ROV reached the top of the ridge at 778 meters, it then moved to the final waypoint target, in search of possible coral habitat. Based on the slope model, this waypoint represented a transitional area between little to no likelihood of coral presence to low to medium likelihood of finding coral. On the soft sediment terrain and in the water column, we observed several fish species, including: Stomias, Cyclothone, possibly two types of eelpouts, witch flounder, black dogfish, catshark (Apristurus), longfin hake, rattails, synaphobranchid eels, duck-bill eels, green eye, gempylids, Antimora, skate, and two other eel types. Several fish parasites were observed, including copepods infesting synaphobranchid eels and an isopod attached to a rattail. At least four different kinds of squid were noted: Chiroteuthis, Illex, Brachioteuthis, and Mastigoteuthis. Several predation events occurred, including a squid eating fish, fish eating something unidentifiable, and crab eating a benthic ctenophore. There were a few items of trash identified, two pieces of monofilament, and an object resembling a five-gallon bucket with a flytrap anemone attached to one side. Very few boulders were noted on the dive; the surfaces were populated by flytrap anemones, serpulid polychaetes, white sponges, and Cottunculus were observed resting at the base of these hard substrates. The boulders appeared rounded, worn, with potentially a manganese iron crust, likely glacial erratics. One of the boulders had a large egg mass on the surface. However, there were some boulders that we were unable to characterize due to limited time. In addition, we saw a large egg case (~10 centimeters across) on the seafloor. Before leaving the bottom, a large shark, identified as a Greenland Shark, was observed in the Seirios camera view, and the Deep Discoverer ROV was able to capture the shark on video. What a way to end a fabulous cruise! The ROV left bottom at 2011 UTC from a depth of 783 meters.
Today we had a deep dive along the southwestern wall of Welker Canyon. The dive started late because there was fishing gear along our planned dive track, and despite a plan to dive at a new target away from the lines, the gear continued to drift toward the ship and remotely operated vehicle (ROV). We waited until the fishing vessel removed the line, moved to a safe distance away from a high flier float observed after fishing gear was removed, and then continued deployment of the ROV to the seafloor. While our new track was off the planned waypoints, it still proved to be a very interesting dive. The track started at the base of a wall and transited up a steep slope and around a promontory. The track continued up a sedimented slope, until we reached a ledge. We then changed course and descended back down the wall. The beginning of the dive was characterized by high diversity of corals, including Anthomastus, bamboo (Kerotoisis), Paramuricea, cup corals, and Acanella. We also observed another purple coiled egg mass, possibly from a nudibranch. Along the sedimented slope, we observed extensive colonies of Paramuricea with scattered xenophyophores throughout. The steep slope examined in the later part of the dive included multiple large colonies of Bathypathes-related, cup corals, Paragorgia, octopuses, sea pens, and encrusting zoanthids. Several caves, deep concavities or amphitheater shaped curves in the rock wall, clear erosional features were observed. Octopuses were often observed in these depressions and under large rock ledges. There were multiple areas where a thin rock layer failed and revealed clean rock faces. We also observed some large, deep “burrows” or “pipes” of mysterious origin. A few different fish species were encountered at the base of the wall, including cf. Gaidiropsarus, oreo, a skate, and an Antimora. At least 17 species of corals were observed throughout the dive, including Bathypathes, Bathypathes-related, Parantipathes, Anthomastus, Paramuricea, Keratoisis, Solenosmilia, Paragorgia, Acanella, Swiftia, Acanthogorgia, unknown octocoral, Clavularia, Anthothela, sea pen, Thourella, and Radicipes. At the end of the dive, we observed an enormous anemone, more than 30 centimeters in diameter, with a polychaete attached to a tentacle. The ROV left bottom at 2130 UTC from a depth of 1,407 meters. Midwater transects were conducted during ascent.
Today we had a deep dive along the southeastern wall of Oceanographer Canyon. The remotely operated vehicle (ROV) was on bottom at 1321 UTC at 1,246 meters. The dive track started at the base of a wall and transited up a steep rock slope, with intermittent sedimented ledges, then transitioned to a softer sedimented slope, finishing up at a steep promontory. The dive was characterized by dense colonies of Paramuricea of similar sizes. On the steeper areas, we observed cup corals, Clavularia, Acanella, and other bamboo corals. One large (~ 25 centimeter diameter) cf. Placogorgia was noted, with no obvious ophiuroid associates, despite the presence of several ophiuroids on Paramuricea nearby. During the latter half of the dive, the ROV traversed a sedimented plane with clear ripple marks, signifying consistently high current flow and direction. Beyond the rippled area, on the sediment plain, there were several burrows with a semi-consolidated mud periphery and several white carnivorous sponges, some with eggs. We encountered multiple colonies of cf. Placogorgia and Paramuricea towards the end of the dive, attached to rocks scattered over sedimented slope. Several of these colonies were covered with yellow zoanthids. At least 16 species of corals were observed, with octocorals remaining the most diverse: Swiftia, Acanthogorgia, Paramuricea, Placogorgia, Anthomastus, Acanella, Thourella, cup corals (cf. Javania, Desmophyllum), Parantipathes, Bathypathes, Bathypathes-related, Paragorgia (white and pink), cf. Keratoisis, cf. Eknomisis. Anthothela, unk. bamboo, Solenosmilia, and Clavularia. A few fish species were observed, including black dogfish, Antimora (with isopod parasites), Cottunculus (two, one with isopods), gaidropsarus, synaphobranchids, grenadiers, brotulids, longfin hake, and witch flounder. Several fresh rock fractures were observed, revealing clean surfaces, and rock piles were present at the base of some of the steep slopes. Within the fractured rock, we observed a fossil, possibly an ammonite, at the base of a rock wall. We also observed several coral colonies laying prone on the sedimented rock, possibly knocked over by rock fall. Trash included a ribbon entwined on a dead coral skeleton and monofilament laying on the sediment surface. Dive ended at a steep promontory with large colonies of Paragorgia at 872 meters. The ROV was off bottom at 1959 UTC at 891 meters.
Deep-sea coral provides a habitat for many other animals. In this image, a pycnogonid or sea spider may be feeding on an anemone while both of them are living on a Paramuricea coral.
Today we had a deep dive along the southwestern wall of Lydonia Canyon. The remotely operated vehicle (ROV) was on bottom at 1,236 meters, ready to start exploring at 1328UTC. The dive track started at the base of a wall and transited up and around a promontory. The primary geological attributes seen included rock walls with erosional features, clear ledges of harder rock, light in color, possibly consisting of chalk or limestone. The dive was characterized by scattered patches of corals living on the rock face, including Swiftia, Paramuricea, bamboo, and Anthomastus. Swiftia was extremely common throughout the dive. In contrast, a high abundance of fauna were observed living on the underside of ledges, including bivalves, Solenosmilia, cf. primnoid, cup corals, squat lobsters, and sponges. Scale worms, ophiuroids, a few solitary hydroids, and sipunculids were observed on sediment laden rock slopes. Two individuals of Neolithodes were observed clinging to the rock face, one of which had barnacles attached to its shell. Two grey/purple shrimps, cf. Glyphocrangonidae, were imaged on sedimented rock. These were observed on a previous dive this leg. At least 15 coral species were observed (Swiftia, Paramuricea, Paragorgia, Anthomastus, bamboo-unknown, white stoloniferous coral, sea pen, Bathypathes-related, Keratoisis, Solenosmilia, Parantipathes, Clavularia, cf. Desmophyllum, cf. Javania, Primnoa, Paragorgia). Fishes included black dogfish, chimaera, ophididae, halosaur, synaphobranchid eel, Chaudiolus, long-fin hake, grenadier, flounder, Notocentridae (spiny eel, first time observed this expedition), and cf. Cyclothone.
For the first time this cruise, we observed a purple deep-sea nudibranch, Tritonia sp., known to consume stoloniferous corals. In addition, an egg mass, likely from a fish, was found on Bathypathes-related black coral. We observed two potential predation events, a sea star sitting on an Anthomastus octocoral and a pycnogonid with its proboscis touching an anemone attached to a Paramuricea. At the end of the dive, we saw a large Paragorgia, covered with ophiuroid associates. The ROV left bottom at 1953 UTC at 1,136 meters.
If you look closely, you can see a ctenophore, or comb jelly, being digested inside the larger predatory beroid ctenophore.
Today’s dive followed a shallow dive track along the northeastern wall of an intercanyon between Powell and Lydonia Canyons. The remotely operated vehicle (ROV) was on bottom at 1310 UTC at 655 meters. The dive track traversed similar sedimented terrain from start to finish. The soft sediment was punctuated by small to large rocks that were typically populated by flytrap anemones, sponges (yellow and white), hydroids, shrimp, squat lobsters, and fish (longfin hake and Sebastes sp.). Other fish observed included witch founder, black belly rose fish, goosefish, eelpout, rattails, synaphobranchid eels, skate, and a juvenile cf. Beryx. One unidentified fish with distinct dorsal and pectoral fins, with extremely elongate posterior region, was observed. Epifauna on the soft sediments was dominated by Hyalinoecia sp. (quill worms), small zoanthids?, Cancer sp. and Chaceon quinquedens crabs. Rocks included boulders with variety of sizes of gravel scattered around and a moat developed around periphery. Rounded rocks considered to be dropstones were observed throughout the dive.
In the water column, we observed midwater fish (Stomias sp. and myctophids), snipe eels, barracudina, squid (Brachioteuthis sp.), siphonophores, salps, amphipods, two types of ctenophores (beroid and lobate), and shrimp (including Sergestes sp.).
Notable observations included a possible pink flatworm (not observed on dives to date); Brachioteuthis mating; mating red crabs sharing a fish; and several other predation events, including a red crab eating a squid, an anemone catching a midwater fish and squid (got away), a Cancer crab eating a dead red crab, and a swordfish knocking over a red crab perched on a boulder. Only one piece of trash, tentatively identified as a sheet of metal, was observed on the dive.
Dive #10 was along the northeastern wall of an intercanyon area between Heezen and Nygren Canyons. The remotely operated vehicle (ROV) was on bottom at 822 meters. The dive track traversed several transition zones, allowing us to examine a suite of habitat types and diverse geological features. Specifically, the track initially transitioned from soft sediment over rocky ledges to sediment with coral rubble, then a steep slope with variegated wall structure. The wall was composed of thinly layered bedding planes, with ledges populated with various fauna, including sponges, cup corals, octocorals, colonial scleractinians, bivalves, seastars, fish, anemones, zoanthids, shrimp, and a few urchins. Iron-stained sediment was present in a few areas, sometimes associated with a yellow-white film covering the red discolored sediment, possibly microbial in origin. The ROV reached the top of the steep slope at 689 meters, and the substrate changed to a sediment field with scattered rocks of various sizes. These rocks consisted of talus type and glacial erratics (rounded stones dropped from glacial or icebergs as the melt), many with well-developed current moats or depressions around their perimeter. A majority of the rocks from 500-689 meters were colonized by encrusting sponges and anemones and associated with several mobile fauna including squat lobsters, red crabs, and a variety of fishes. Many also had small colonies of Acanthogorgia. Cancer crabs also were observed along the sediment plane at the top of the slope.
Throughout the dive, several fish species were observed, including rattails, Antimora, black dogfish, catshark, witch flounder, longfin hake, Sebastes, eelpout, ophidiidae (in cracks in wall), tonguefish, two different skates, fathead, barracudina, and black belly rose fish. At least 15 species of corals were documented during the dive, including cup corals (Javania and/or Desmophyllum), Acanella, Acanthogorgia, Anthothela, Lophelia pertusa, Primnoa, Solenosmilia?, unknown white octocoral, Paragorgia, Clavularia, white stolonifera,Paramuricea (yellow), Paramuricea cf. placomus (purple), and an unknown soft coral.
Highlights from today’s dive were the large Lophelia pertusa colonies, additional examples of predation, a new soft coral observation, and several small colonies of Acanthogorgia on rocks scattered around 500 meters. One crab trap was observed near the top of the slope (696 meters), with corals and seastars attached at the base of the trap. Fish appeared abundant and diverse, mostly present in sedimented areas, some near boulders, and others within concavities in the rock wall. Swarms of amphipods, many ctenophores, and multiple salp chains were present in the water column as the ROV traversed the sedimented plain at the top of the slope. The ROV was off bottom at 2015UTC at 498 meters.
The Okeanos Explorer’s ROV team uses the weather day to fine tune the vehicles and preform any maintenance that is required.
We woke up this morning to find that the seas and wind had come up overnight just as was forecasted. The ship’s captain, expedition coordinator, mapping team lead, and remotely operated vehicle (ROV) team lead all gathered on the bridge just after sunrise to assess the weather and decide if we could deploy the ROV or not. Unfortunately, all were in agreement that the weather was too bad for ROV operations. So emails were sent and notes passed to shore to let our shore-based science team know that there was not going to be a dive and that they needed to find less interesting things to do with their Saturday. The ROV team was able to use the weather day to catch up on a little rest and a lot of paperwork. While a weather day may mean less work for most the mission personnel, it certainly does not for our mapping team. They have to create a line plan and run the ship sonars an extra 12 hours a day. Just because it is too rough for ROV operations does not mean that we still cannot collect high-resolution sonar data. Today, we have been mapping an area of interest to the U.S. Geological Survey who is trying to understand how and why landslides occur on the continental shelf slope. As the day comes to a close, we are all closely watching the weather forecasts with fingers and toes crossed that we will be able to dive on Sunday.
NOAA’s ROV Deep Discover, or D2 for short, explores an underwater “forest” of corals. It takes hundreds of years for corals to grow as big as the ones we found in Heezen Canyon. Some deepwater corals are believed to live as long as 4,000 years.
Dive #9 was a shallow dive along the southwestern wall of Heezen Canyon. The remotely operated vehicle (ROV) was on bottom at 1315 UTC at 924 meters. The dive track started at an area with soft sediment and small rocks. The ROV transited up slope along a steep wall to the top, then along soft sediment and back down the northern part of a steep slope. The first rock feature was minimally encrusted by fauna, including sponges and anemones. At least 13 species of corals were observed either attached to the vertical face or on small rocks at the top of the slope, including: Anthomastus, unknown bamboo, Acanella, two species of cup corals, Solenosmilia, Paramuricea, Primnoa, Paragorgia, Acanthogorgia, Anthothela, Lophelia pertusa, and Clavularia. Shark egg cases were observed attached to Paramuricea, Paragorgia, and possibly bamboo coral. Fish species included Rhinochimaera, black dogfish, witch flounder, Sebastes, black belly rosefish, synaphobranchidae, ophidiidae, long fin hake, offshore hake, eelpout, hatchetfish (midwater), and mychtophidae (midwater). The steep slope was characterized by large rocks composed of mudstone or siltstone with cracks and thin to no sediment. Along the steep wall, chutes from possible turbidity flows were observed. Also, the geology of the dive track consisted of well exposed, but highly eroded (possibly Oligocene/Eocene age) outcrops, complex failure and sediment transport/canyon cutting morphologies, and another example of the possible relationship between lithology, sediment stability, and associated sessile encrusting organisms. The sediment-laden top was interspersed with various sized rocks, usually populated with small colonies of Acanthogorgia, with shrimp associates, and sponges. Highlights of the dive included the enormous Paragorgia, Primnoa, and Paramuricea colonies that were attached to the vertical face. Other corals were interspersed among these > two-meter colonies, including very large cup corals attached to the underside of ledges. Predation was also observed, including an eel eating a shrimp, a small fish (possibly midwater) attached to a solitary hydroid, and a fish escaping an octocoral. ROV was off bottom at 2006 UTC at 742 meters.
Dive # 8 was on a shallow section along the northeastern flank of Nygren Canyon. The remotely operated vehicle (ROV) was on the bottom at 1526 UTC at 910 meters. The dive track transited over soft sediment with large boulders to a steeply sloped terrain, with rocks that were heavily encrusted and layered with sediment. Various fauna populated the dramatic rock features throughout the dive. The edges of large rock ledges were colonized by high abundances of solitary corals, sponges, brisingid sea stars, and colonial scleractinians. Later in the dive, the following corals were observed: Acanella, Paramuricea, Jasonisis and Paragorgia on ledges or small sedimented patches. In some areas, there were large surfaces of the rocks encrusted with stoloniferous corals. At least 12 additional species of corals were documented, including four types of stoloniferans (Clavularia, white, pink, and yellow type), unknown bamboo, cup corals (at least two species), Solenosmilia, Lophelia pertusa, Parantipathes?, Anthomastus, and Anthothela. There were several examples of one coral colonizing another, including Anthothela on Paramuricea and Anthothela on Paragorgia. As with the previous canyon dives, sea stars were diverse and included Chondraster, Tremaster, brisingids, and a yellow sea star. Squat lobsters appeared more abundant on sediment than corals, with a few individuals observed on Jasonisis that differed from the sediment associates. Red crabs were relatively abundant and two red crabs were noted eating a pyrosome (tunicate-colonial, free floating). There seemed to be a higher diversity of shrimp, with multiple species observed on individual coral colonies. A high diversity of fish fauna was noted throughout the dive and included black dogfish, Antimora, synaphobranchid eels, rattails, Psychrolutidae (fathead), Sebastes, Helicolenus, Hoplostethus, Coryphaenoides, Symphurus, and Hydrolagus. A few highlights from the dive included a large parasitic isopod attached to Hoplostethus, which seemed to interfere with the fish’s ability to swim. Also, a Sebastes was observed eating another fish, with the tail sticking out of its mouth. Several shark egg cases were found attached to Paramuricea throughout the dive, which was the first time during this leg that these had been noted. Overall, very few cephalopods were observed, including a bobtail squid, an unknown squid (possible Illex or Gonatus), and an octopus (Graneledone verrucosa). As we transited up slope, the rock wall appeared to be composed of sandstone, with patches of dark, manganese-coated surfaces. As with our previous canyon dives, we found trash along the dive track, including plastic, traps, and coiled cord. The dive ended over soft sediments where burrows, red crabs, and a variety of fishes were observed. The ROV was off bottom at 661 meters at 2240 UTC.
Today’s dive was along a deep section on the southwestern flank of Heezen Canyon. The remotely operated vehicle (ROV) was on bottom at 1,710 meters. For the initial part of the dive, the seafloor was composed of soft sediment with scattered rocks of various sizes and colors. Mudstone slabs, glacial erratics (igneous rock) and granite were among the rocks observed at the base of the slope. One large block was likely dislodged from close by, given that it was relatively intact with little debris nearby. Several fauna were attached to the rocks, including anemones, brisingid seastars, white holothurians, and Anthomastus, including several small recruits. On the sediment surface, several xenophyophores, brittle stars, few sea pens, sea urchins, and a sea spider were present. Several fish were observed during the dive. Trash was noted throughout the dive, particularly at the base of the main wall, including line and plastic material. As the ROV ascended the rock wall, the rock face was extensively fractured and had several horizontal striations with multiple holes. The dive track moved upslope along very steep features, sometimes > 90 degrees. The ROV continued upslope to the top of the steepest feature, transited shortly on a long sediment ledge, then was redirected downslope to the steepest feature in the area. The sedimented ledges that were present at the base and top of the slope were often colonized by deepwater coral, pale brittle stars, and xenophyophores. As the ROV transited up slope a second time, and moved laterally to the northwest, a few encrusting fauna dominated the rock assemblages, including brisingid sea stars, cup corals (cf. Desmophyllum), sponges, and anemones. Abundances of these taxa were patchy throughout, with some rock surfaces heavily encrusted while other had very few. Other corals observed in low abundance including the Bathypathes-like and Stichopathes (black corals), Acanella (bamboo, one with roots visible), Umbellula (sea pen), Acanthogorgia and Radicipes (octocorals), Solenosmilia (colonial hard coral), Clavularia (stoloniferan). On two occasions, a zoanthid mat carpeting rock surfaces was noted living adjacent to cup corals and anemones. A few other sea star species were observed clinging to the rock faces and laying on the sediment surface. Other notable observations during the dive included active predation when a squid was seen eating a fish, chaetonatha (arrow worms) floating in the water column, caprellid amphipods, a purple and pink polychaete laying on the sediment surface, and the retracting proboscis of an echiuran. Periodically, the ROV came upon rock faces that appeared recently exposed, with a smooth surface. In addition, there was evidence of high current flow in certain areas where ripple bed forms were clearly visible in the sediment surface. The dive ended at 1937 UTC at a depth of 1,621 meters.
This pink geometric pattern we found in Nygren Canyon over a mile under water stumped the scientist for a while. The current thought is that it is some type of mollusk egg case.
Dive #6 at Nygren Canyon was very exciting. The remotely operated vehicle (ROV) was on bottom at 1325 UTC at a depth of 1,579 meters. While traversing over soft sediments, the seafloor was scattered with shell debris that transitioned to more abundant shell, coral skeleton, and small, dark rocks. Abundant organisms observed over or on the sediments included eels, xenophyophores, and brittle stars. There were a few sea pens and sea urchins also observed. The slope changed to more rugged topography, composed of dark, manganese encrusted rock. The hard substrate was populated by several taxa that have been documented previously on this expedition, including limid bivalves, stony corals, and sponges. On the rock surface, a coiled, pink mass resembling a gastropod egg mass was observed. At 1,558 meters, the rock face changed to a lighter color, consistent with carbonate, and multiple patches of mussels populated cracks within the rock. We had discovered a seep. Other organisms found within the mussel patches included serpulids, scaleworms, gastropods, and bacterial mats. Light, white fluffy material floated away from one of the mussel patches. Within five minutes, the ship was able to engage two seep experpts on shore to help us document the discovery. Several species of corals were documented throughout the dive, most of which occurred on the exposed rock face, but some were also found within the softer sediment at the beginning of the dive (e.g., sea pens). At least 17 octocoral species; three black coral species; three to four scleractinian species, including colonial (Solenosmilia) and solitary (cup corals, cf. Javania, Desmophyllum) forms; and three sea pens were noted. Other interesting observations were the first documentations of the black coral, Leiopathes, and a corallimorpharian for this expedition. An unusual sediment laden crab had its carapace decorated with a sponge. Dead coral skeleton provided a substrate for several species, including three species of corals, anemones, hydroids, barnacles, and crinoids. Other species associated with corals included squat lobsters on the black coral and bamboo coral and amphipods on other black corals. Large sponges with associated brittle stars and crinoids were found on the steep slope. The dive ended on steep feature composed of dark, manganese coated rock. The ROV was off bottom at 1945 UTC at a depth of 1,310 meters. After the ROV dive was completed, we conducted a CTC cast over the new seep site then conducted a couple hours of sonar mapping at the same location to make certain that we had well documented the unexpected seep site.
Our fifth dive took place on the south side of Mytilus Seamount and contrasted with the north wall dive in many ways. The remotely operated vehicle (ROV) was on bottom at at 3,262 meters. The terrain was gently sloping sandy sediment with scattered cobbles, including darker-colored manganese-coated basalt and lighter-colored stones, potentially composed of carbonate. More fish were noted duing this dive than were on the north side of the seamount; they were present mostly on the sedimented areas at the beginning and end of the dive. High abundances and diversity of sponges were noted throughout the dive once we ascended to hard substrate, including several types observed on Mytilus dive #4: “tulip” shaped, vase sponges, and some new forms, primarily hexactinellids. A few crustaceans were observed, including hermit crabs with anemone houses, shrimp, and squat lobsters (Munidopisidae). The first coral noted on the dive was a sea pen observed on the sedimented seafloor. The general substrate throughout the dive was composed of large basalt ledges with thin to thick sediment drape, steep rocks, and some smooth basalt pillars transitioning to mostly sediment with cobble at approximately 2,697 meters. Up to 13 octocorals were observed during the dive, including our first observation of Calyptrophora. Three types of black corals were also noted. We noted discrete zonation present on a bamboo coral, with brittle stars, barnacles, and zoanthids covering different sections of the mostly dead coral. A few seastars observed during yesterday’s dive were also noted today, including cf. Evoplosoma (coral eating type), Hymenaster, and Pteraster. At the end of the dive, we noticed a piece of wood that was heavily bored, with squat lobsters perched on one end. The ROV was off bottom at 2126 UTC, leaving from a depth of 2,593 meters.
NOAA’s ROV, Deep Discoverer, examines a deepwater coral colony on the north flank of the almost wholly unexplored Mytilus Seamount.
Dive 04 took us to Mytilus Seamount, one of the least explored seamounts of the New England Seamount Chain. The dive started late after an issue with the traction winch that required maintenance. While the remotely operated vehicle (ROV) descended to the seafloor, there were very few planktonic organisms observed. The ROV reached the bottom at a depth of 3,271 meters. The dive track ascended a steep portion along the north side of the seamount, from ~3,270 to 2,750 meters. The geology was characterized by a combination of gentle and steeply sloping basalt pillars that were smooth in texture, interspersed with ledges or steps covered with sediment drape. Periodically, piles of small, dark rocks were observed. All the rocks had a manganese coating. At the start of the dive, various sponges, mostly glass sponges of different forms, populated the rock walls. These included long stalked forms with a “tulip “shaped head, vases, “witches” hat, globular, and “rose” shaped. Various species of brittle stars, stalked and non-stalked crinoids, and sea cucumbers were abundant along the rock walls and on the sediment ledges throughout the dive. At around 3,250 meters, the first corals were observed. As the ROV continued up slope, additional corals, including a few different species of bamboo corals as well as Chrysogorgia, Paragorgia, Paranarella, Anthomastus, Corallium, Convexella, and two black coral species were noted. No scleractinian corals were documented on the dive. Other fauna observed included hermit crabs, squat lobsters, the coral-eating seastar, several bryozoans, two featherduster polychaete worms, and barnacles. At 2,806 meteres, a large bamboo coral colony with associated crinoids was imaged. Several large bamboos were documented throughout the remainder of the dive. At the end of the dive, a pillow lava was observed. Very few fish, including a frogfish, cusk eel, and synaphobranchid eel, were documented.. Our dive at Mytilus Seamount represents the most comprehensive investigation of benthic communities at this seamount to date.
NOAA’s ROV, Deep Discoverer, examines a collection of deepwater corals on the western wall of Oceanographer Canyon.
The third dive took place on the western wall of Oceanographer Canyon and was characterized by high diversity and abundances of corals. While descending to the bottom, several salps were observed suspended in the water column. The remotely operated vehicle (ROV) reached the seafloor at a depth of 1,236 meters. Once on the bottom, there were rocks of various sizes, all with some level of sediment drape. These rocks had very angular faces, with no obvious signs of erosion. Roots from an Acanella coral extended down a rock face, much like tree roots, which had not been observed by the scientists before. Many quill worms were present on the soft sediment. At 1,217 meters, we observed a squid eating a midwater fish. Several large rocks with steep faces were the primary features examined for the remainder of the dive. Hard substrates were populated by several large Anthothela, Paramuricea with ophiuroid associates and various sponges, including yellow sponges and other hexactinellids. Around 1,210 meters, coral abundance increased dramatically and time was spent imaging corals, their associates, and rock-associated fauna. Two black corals, Parantipathes and cf. Bathypathes, were imaged with their associates, chirostylid squat lobsters and scaleworms. At 1,204 meters, a different type of shrimp, grey/purple in color, was resting on the rock surface near an Acanella bamboo coral and cup corals. A t-shaped echiuran proboscis was imaged retracting into the sediment nearby; this animal has not been observed on any of the dives thus far, including dives on the first leg of this expedition. At ~ 1,150 meters, there was a distinctive change in the geology to eroded and heavily sculpted mudstone. We found an unusual bacterial mat coating the seafloor in an area of collapsed soft sediment. There was no seafloor seepage noted throughout the dive, so the underlying source for bacterial production was not obvious but possibilities are numerous. The primary highlights from the dive were the high abundances of Paramuricea and bamboo corals and the range of sizes observed along the dive track, with the largest colonies appearing at the end of the dive. Overall, there was a north to south trend in current flow and many of the corals extended from the walls perpendicular to the southward flow, possibly to take advantage of the flow and associated food flux. It was a great dive overall.
The second dive of leg 2 was at a minor canyon near Shallop Canyon. While descending to the bottom, numerous salps and fine marine snow were seen suspended in the water column. The Deep Discoverer remotely operated vehicle (ROV) reached the bottom at a depth of 1,131 meters. The seafloor was mud bottom interspersed with burrows, swimming eels, and squid. The sediment was relatively homogeneous, with no rubble or rocks, which indicates little or no sediment traveled down the canyon to the seafloor. Continuing along the dive track, additional fish were noted and a rubber glove (trash) was partially buried in the sediment. At a depth of 1,118 meters, the ROV came upon a large rock with no debris at the base, a thin sediment coating on the top, and heavy sediment drape at the base. Small octocorals, with only a few polyps, had colonized the rock feature. Their small size suggests recent colonization. At 1,117 meters, the ROV transited to a steep and tall rock face that had weak layering and relatively heavy erosion. At the base of the large rock face, piles of dead stony corals and live bivalves gave the clue that something interesting may be just above. At 1,094 meters, the ROV ascended up the rock feature and imaged many of the rock associates, including hydroids, squat lobsters, various sponges, and many limidae bivalves. While exploring the rock face, several sessile invertebrates were found attached to the wall, in cracks, crevices, and overhangs. Large black corals were particularly numerous on the wall, with several different types of creatures hanging on their branches. The rock wall, potentially Eocene in origin (~56 to 33 million years old), contained numerous holes, which provided a habitat for a polychaete worm, squat lobsters, and encrusting sponges. The ROV reached the top of the feature at 1,031 meters, which was highly sedimented and contained similar fauna and features as the base of wall, including eels and burrows. Once it was clear that the ROV had crossed the steepest feature, there was a ship move to head back to the cliff and continue exploring the wall to the north. At a depth of 1,034 meters, while exploring the wall, several types of sea stars and urchins were seen. The ROV video obtained some amazing footage of several small amphipods perched on a hydroid. The ROV left bottom a bit early because the seas were picking up.
The first dive of leg 2 explored deep-sea landslide debris and scarps between Alvin and Block Canyons, at U.S. Geological Survey Hazards 1 site. We transited through a landslide debris field and continued up slope, where we finished the dive exploring the top of the scarp. Few rocks of various sizes were scattered on the sediment surface. Some of these rocks were fairly clean, with few animals, while others were heavily populated by flytrap and unknown anemones, hydroids, snails, and hermit crabs. The sediment topography included small hummocks, large burrows, and clay balls scattered over the sediment surface in some places. Squat lobsters, red crabs, and shrimp were observed residing within burrows made of semi-consolidated mud. Throughout the course of the dive, we observed several species of fish, including rattails, flatfish, and eels. We also saw active predation by fish on other fish and invertebrates, as well as parasites attached to the outside of eels.
Leg 2 Commences!
New York, New York, is a beautiful city to start a cruise from. After a couple days of rest in the Big Apple, it is time to get back to work exploring the Western North Atlantic. Shortly after lunch, the Okeanos Explorer pulled away from pier 36 on the lower east side of Manhattan and headed for sea. There is nothing like getting a sendoff from Lady Liberty herself as we left the city and headed toward the Verrazano Narrows. It is still amazing that it only takes several hours of streaming out of New York until we will be in unexplored deep water. There is no better example of how little we know about the ocean than to realize that there are unexplored regions of the continental slope just 60 to 100 miles off shore. Less than 100 miles off shore from America’s largest city lay places and animals that have never been seen by human eyes. Tomorrow will bring our first remotely operated vehicle dive of leg 2 and who know what we may discover right in America’s backyard.
16 dives in 16 days, and everyone is still smiling! We had a great first leg of the Northeast U.S. Canyons 2013 Expedition. Mission personnel pose for a group photo as NOAA Ship Okeanos Explorer steams to port in New York, New York.
Cruise Leg 1 Comes to an End!
Following the completion of yesterday’s remotely operated vehicle dive, the ship began transiting back to land and pulled into port in New York, New York, today at approximately 1200. Onboard personnel are busy wrapping up the cruise, cleaning up spaces, finalizing cruise documentation, and preparing for the in port. The ship will spend six days in New York, New York, before departing for cruise leg 2 of the Northeast U.S. Canyons Expedition on July 31.
A squat lobster, Munidopsis sp., is associated with a branching stony coral on the east wall of a minor canyon explored on July 24, 2013.
The final dive of the expedition, dive 16, was conducted in an inner canyon area (in an unnamed minor canyon) informally named “Gauntlet Minor.” The purpose of this dive was to conduct a first-order characterization of the geomorphology and benthic habitats on both the east and west walls. The remotely operated vehicle Deep Discoverer (ROV D2) reached a slightly sloped area covered in soft sediment in the northern region between the east and west walls at a depth of 1,110 meters. Anthropogenic trash and debris, including monofilament line and balloons, were observed in this area. Fishes were prevalent, including cutthroat eels, witch flounder, and several rattails. Boulders, disarticulated bivalve shells, and coral rubble, including dead, broken attached pieces of cup corals and a branching stony coral, were apparent on the seafloor. Several octocoral colonies were seen on the boulders. D2 moved up slope and reached a vertical wall face with a higher abundance of fauna (animals), including stony corals and octocorals, from 1,078 - 1,030 meters. The ROV continued upslope over a thicker sediment cover with no corals to the top of the wall at 1,020 meters. D2 then moved northward and came back down slope, seeing an abundant line of coral colonization at approximately 1,030 meters, with the same dominant fauna. The ROV continued west over a mostly soft sediment bottom with scattered coral and rock rubble at the base of the western canyon wall. Moving upslope on the western wall, it was noted that the same type of faunal assemblages was observed as on the east wall, yet with greater apparent density at 1,070 meters depth. Near the end of the dive, a few additional corals were observed that were not seen on the east wall, including an unidentified black coral and a few bamboo corals. The ROV departed from the seafloor at a depth of 1,030 meters.
Dive 15 focused on exploring the geomorphology and biological communities of Block Canyon starting at a depth of 1,134 meters. Remotely operated vehicle Deep Discoverer (D2) descended onto a soft sedimented seafloor composed of silt and clay mixed with scattered rocks and boulders of various sizes. Numerous fishes were evident, including cutthroat eels, red crabs, blue cod, witch flounder, and grenadier. Rocks were colonized sparsely by small bamboo corals accompanied by mysid shrimp hovering around the colonies. As D2 transited to the base of a vertical rock wall, octopus and coral colonies, including one hosting a ring anemone and a brittle star, were observed. At 1,111 meters D2 reached the base of the vertical wall, which was horizontally stratified with layers of carbonate and porcellanite, a hard, dense sedimentary rock somewhat similar in appearance to unglazed porcelain, which here appeared stronger and less bio-eroded compared with the carbonate layers. Continuing upslope, bamboo coral, limid bivalves, and two species of stony corals were observed before reaching a promontory feature near 1,030 meters – the most extensive area of concentrated colonization. The most abundant fauna were bivalves, occurring in linear arrays along the wall. Octocorals, bamboo corals, and a few black coral colonies with brittle stars, polychaetes, and mysid shrimp associates were observed. D2 moved downslope until reaching the base at a depth of 1,116 meters, and then returned upslope, noting the same patterns of faunal colonization along this traverse. During the last 30 minutes of the dive, D2 approached a flat sedimented area and then a relatively barren second wall, with a few bivalves and sponges. D2 left bottom from a depth of 995 meters.
Close up view of a stalked crinoid’s (sea lily) mouth and arms. At least two species of crinoids were noted during the dive today at Block Canyon, including stalked crinoids.
Dive 14 was conducted deep in Block Canyon, exploring the geomorphology and benthic communities on the east canyon wall from a depth of 2,131 meters. Upon reaching the bottom, the remotely operated vehicle Deep Discoverer (ROV D2) discovered soft sediment composed of silt and clay scattered with medium size boulders. Overall, few fishes and megafauna (animals visible through imagery) were observed, and sessile (stationary) fauna were sparse, including stalked crinoids, throughout this dive. In contrast, brittle stars and white sea urchins were abundant. Extensively bio-eroded mudstone boulders and blocks with a notable lack of faunal colonization were documented. A few small cup corals were attached to the sides of the blocks, and octocorals and glass sponges were the dominant fauna. D2 reached the base of the canyon and continued to move up slope along a wall feature appearing younger, weaker, with portions of the surface showing collapsed features, and extensive debris fields were noted at the base. As the ROV continued moving up slope to the top of the wall, fewer attached fauna were noted on the wall surface. After the sedimented top was documented, D2 transited down slope toward another promontory. Octocorals were observed on the wall surface at 2,087 meters and several cup corals were encountered under a small overhang. D2 continued to survey along a contour across the promontory toward the end of the dive, where brisingid seastars were abundant and facing east into the current. The ROV left bottom at a depth of 2,062 meters.
Corals, including cup corals and bubblegum corals reside on the hard substrate near the edge of the mussel bed.
Dive 13 was conducted at “New England Seep 1,” further investigating gas seep areas previously detected in sonar data and ground-truthed during a remotely operated vehicle (ROV) shakedown cruise this past June. From these recent dives, it was known that seeps in this area hosted chemosynthetic communities at approximately 1,400 meters deep. The ROV arrived at a soft sedimented seafloor with some small pebbles and a few coral colonies at 1,409 meters. Red crabs, rattails, cutthroat eels, urchins, black dogfish, and mesopelagic fishes were also noted. The ROV continued to the first waypoint following a sonar target to edge of a large mussel bed at a depth of 1,420 meters. This bed was mixed with live and dead mussels of various sizes (including thousands of what can be considered as relatively recent mussel recruits ~2-3 centimeters in length), with most of the dead mussels observed on the peripheries of the bed. Deep Discoverer (D2) transited several directions to get an estimate of the size of the bed (~50 meters by ~80 meters), although the mussel bed likely continued farther to the north. A line of carbonate blocks extended along the entire eastern edge of the mussel bed. Numerous variably sized white and pink bubblegum corals and cup corals were attached to these carbonates. Close-up images of the mussel assemblages revealed caprellid amphipods, scale worms, Alvinocaris shrimp, and abundant gastropods (snails). Next we searched for the multibeam sonar-detected bubble (presumably methane) plumes using D2’s camera sled and sonar. Bubbles were discovered and imaged in apparently uncolonized soft sediments at a depth of ~1,421 meters. Sediments with bacterial mats and white “marshmallow” material were observed in patches in and around the mussel bed. This mussel bed and corals were surveyed for the majority of the dive, as throughout the afternoon numerous live interactions with the Aquarium of the Pacific occurred. Imaging of white and red bubblegum corals revealed numerous ophiuroids (brittle stars) associated with the colonies. Many octopods and crabs were also observed. The ROV left bottom from a depth of 1,422 meters.
A rarely observed deep-water skate is imaged on the seafloor of Veatch canyon during a dive on July 20, 2013.
Dive 12 investigated the transition from canyon processes to landslide deposition within Veatch Canyon to explore the relative timing of past landslide events. The remotely operated vehicle Deep Discoverer (ROV D2) descended onto a soft sediment bottom with some bioturbation (the reworking/restructuring of sediments by moving organisms) including feeding traces, hummocks, and burrows at a depth of 2,108 meters. The dive track consisted of moving due north through an area of possible geological transition—from canyon to landslide deposition—before heading southwest up a gradual slope on the west side of the canyon wall. Brittle stars (thousands of individuals) blanketed the seafloor throughout the entire dive. Anemones, sea pens, and polychaetes tubeworms were also abundant. Few fishes were observed overall, but those imaged included the deep-sea lizardfish, tripod fish, halosaurs, rattails, and blue cod. Two species of sea cucumbers and at least four species of sea urchins, including green heart urchins, were common. Stalked crinoids (sea lilies) and white brittle stars were common on the sedimented seafloor, but an encountered piece of wood hosted a non-stalked crinoid and a pink brittle star species. As D2 moved up the gradual slope, previously unseen fauna appeared, including at least three different species of sea pens, lithodid king crabs (possibly juveniles), and bamboo corals. On the sea pens, different brittle star associates were observed. The white brittle stars that occurred on the sediment were not the same as those observed on the corals. Anemones were also noted growing on one type of sea pen. The ROV left bottom at a depth of 1,969 meters.
Dive 11 of the Northeast U.S. Canyons 2013 Expedition explored the geomorphology and benthic habitats of Block Canyon. Remotely operated vehicle Deep Discoverer (ROV D2) descended to a soft bottom seafloor with scattered rock rubble and boulders and an abundance of red crabs and cutthroat eels along the eastern wall at a depth 1,340 meters. Flytrap anemones, hydroids, bamboo corals, and octocorals were attached to the rocks, with many being small recruits. Potential new species of black coral and bubblegum coral were observed. An oreo fish (first of this cruise) was documented at a depth of 1,345 meters. D2 moved upslope to a promontory feature hosting a high abundance of coral rubble. Dense and diverse sponge and coral communities with numerous species of bamboo corals, cup corals, and large black coral were growing on the wall as we ascended to the top of the feature. Small horizontal cracks in the wall were evident. D2 then came back down slope to a depth of 1,335 meters to begin the next vertical transit. At the base, coral rubble was dense and two more oreo fish were observed. The ROV moved upslope, noting similar corals in high abundance and numerous squat lobsters, shrimps, and brittle star associates en route to the top of the wall at 1,239 meters. Of note, chirostylid squat lobsters were only observed living on black corals. At least one skate egg case was observed during this dive. Hard substrate in this area was visually similar to those in both Alvin and Atlantis Canyons and all are possibly in the same age range (Cretaceous/Eocene).
NOAA’s Seirios camera sled images ROV Deep Discoverer during exploration of the eastern wall of Alvin Canyon during a dive on July 18, 2013.
Dive 10 was conducted in Alvin Canyon, investigating the geomorphology and benthic habitats on the eastern canyon wall. Squid, midwater fishes, cutthroat eels, and small shrimp were prevalent in the water column before the remotely operated vehicle (ROV) arrived on soft sedimented bottom at the base of a west-facing wall feature with a light face and horizontal layering (1,088 meters). Cup coral rubble and dark cobbles were observed at the base. The ROV began investigation of a heavily bored, carbonate rock wall with several encrusting sponges, anemones, polychaete tube worms, and corals (c.f., Solenosmilia) growing under the overhangs. As Deep Discoverer (D2) transited upslope at a depth of 1,074 meters, bamboo corals and octocorals (e.g., Acanthogorgia) were noted on an overhang. A layer of non-bored, courser grain rock was between two layers of bored sediment. There was generally a lack of large fauna (animals) colonizing this courser grain rock, and the top of the wall was reached at 1,020 meters. Bamboo corals, limid bivalves, orange encrusting sponge or zoanthid, and a solitary hydroid were noted at the top of the ledge. D2 moved down slope and across a gentle slope of soft sediment with scattered rock. Uncolonized trash, fish, and fauna commonly associated with soft sedimented seafloor were present. Moving up a vertical wall at a depth of 1,056 meters, two juxtaposed walls were noted, with numerous broken slabs at the base and a sediment chute up the middle. A higher abundance of corals, including bamboo and primnoid corals, were noted as D2 continued upslope. Numerous skates and skate egg cases were observed, including at least two with parasites. With the exception of hydroids on exposed coral skeletons, few faunal associates were observed living with corals. Other geological observations included eroded slabs of rock sitting on top of wide ledges that were also in places undercut above. The ROV left bottom from a depth of ~1,010 meters.
Desmophyllum (cf.) dianthus (Cup Coral) is a solitary deep-sea scleractinian, or stony, coral common along the walls of Alvin Canyon.
Dive 09 was conducted on the west wall of Alvin Canyon to characterize the diversity of submarine canyon geomorphology and benthic habitats from 926 to 863 meters. The Deep Discoverer remotely operated vehicle (D2 ROV) arrived at a seafloor covered in soft sediment at 926 meters hosting numerous red crabs, squat lobsters, witch flounder, cutthroat eels, dogfish, and midwater organisms (e.g,. ctenophores). We appeared to be in a nepheloid layer (layer of suspended sediment in the water column) with poorer visibility compared previous dives. D2 traversed large sediment scars with boulders at the end, suggesting they had recently rolled down slope. The boulders appeared to be carbonate cemented sediment, silt/mudstone and clay rich. The ROV reached the base of a vertical wall heavily bored with anemones and polychaetes tubeworms attached, where fishes were abundant and sessile (fixed) fauna including several species of sponges, cup corals and a few bamboo corals were evident. Several “white lines” were running down the wall, and it was noted that they were associated with fissures/fractures of various depths. D2 transited up a very steep vertical wall blanketed in fine, silty sediment with mudstone blocks covered in bamboo corals and sponges. Descending to the base of feature, numerous ctenophores, salp chains, and amphipods (small crustaceans) were observed in the water column. We moved upslope along a rock wall with numerous “white lines” running down the face, with a lack of attached fauna and low diversity of corals. The ROV made its way upslope to waypoint 3, approaching a large vertical wall with numerous corals, particularly solitary hard corals, growing under ledges that appeared to be white, cemented carbonate with light sediment cover. D2 concluded the dive at a depth of 863 meters.
A considered obligate relationship between a specific species of octocoral (cf. Metallogorgia melanotrichos) and brittle star (cf. Ophiocreas oedipus). To our knowledge, these species were previously not known to occur in the Northeast U.S. Canyons Region.
Dive 08 was conducted in Atlantis Canyon, exploring the east wall between 1,800 meters and 1,600 meters to characterize canyon geomorphology and benthic habitats, including possible coral and sponge communities. Remotely operated vehicle Deep Discoverer (ROV D2) arrived at a soft sediment seafloor with scattered rock rubble and outcrops at 1,795 meters. Halosaur fish, white brittle stars, and cutthroat eels were prevalent in this area (yet relatively few fishes were noted during this dive), and sea pens and four species of sea urchins were noted. As D2 moved up slope to the first waypoint, we approached the base of a rock wall that appeared to be calcareous mudstone/siltstone and chalky in appearance. Attached fauna (animals) included an abundance of sponges with numerous shrimp associates. Although corals were not abundantly attached to the rocks, they were diverse. We noted at least 15 species including sea pens, cup corals, and other octocorals at a depth of ~1,750 meters. As D2 continued upslope, a large aggregation of cup corals and sponges were observed on a ledge with dead cup coral rubble below it. At 1,643 meters, we came across an octopus guarding eggs attached to the underside of a ledge. The ROV moved along the wall to waypoint 3, noting extensive fracturing along the wall and capturing imagery benthic ctenophores. D2 transited upslope to cover a broader depth range. One large vertical wall at a depth of 1,637 meters had numerous sponges and a clump of live coral. The first colonies of Acanthogorgia and Acanella were observed before D2 left bottom at 1,622 meters, ending the dive. Currents at the site were considered weak.
A bobtail squid is imaged by ROV D2 during Dive 07 in Atlantis Canyon. The squid is less than one foot in length.
Dive 07 was conducted along the western wall of Atlantis Canyon to characterize benthic biodiversity and habitats as well as collect information about canyon geomorphology. The remotely operated vehicle (ROV) reached a soft sedimented seafloor consisting of fine grain silt/mud at 1,101 meters and hosting numerous burrows and a prevalence of grenadier fish, cutthroat eels, and red crab. The ROV moved over the soft sediment and approached the base of a stratified and heavily bored vertical wall with cup coral rubble scattered around the base. Sessile fauna (stationary animals) were prevalent under one ledge, including corals, bivalves, and a seastar. Squat lobsters were observed inhabiting the branches of both soft and hard corals, and squid eggs were seen in a glass sponge. The ROV continued moving up slope, noting another large vertical wall colonized with bivalves, black corals, and stony corals, but few sessile invertebrates (animals without backbones). The ROV then transited from the face of the vertical wall to move back down slope. At 1,100 meters, we traversed over soft sediment with scattered rock outcrops colonized with sessile sponge and coral fauna. The ROV moved laterally along a vertical wall hosting few animals as it approached the next waypoint. At 1,033 meters, several species of corals, including bamboo and cup corals were noted growing under a ledge, and a rare sighting of a king crab. Moving upslope from 1,010 meters, the ROV transited over soft sediment on a steep slope (~60 degrees) containing several burrows with red crabs, squat lobsters and little sessile fauna. Cutthroat eels, fish including hake and grenadiers, and a few octopi were documented at the end of the dive. The dive concluded at 885 meters.
Amongst the diverse coral community along Hydrographer Canyon, ROV D2 observed a glass sponge containing cephalopod eggs. If you look closely you can see what looks to be a recent hatchling!
Dive 06 was conducted in Hydrographer Canyon, exploring the east wall to characterize and discover benthic habitats and biodiversity, including anticipated deep-sea coral and sponge communities, as well as examine canyon geomorphology. The Deep Discoverer remotely operated vehicle (ROV D2) reached the seafloor at a depth of 907 meters and settled over a soft sediment area with scattered rock boulders. A strong current persisted from the south, as we began our transit to waypoint 1 and observed numerous cutthroat eels, blue cod, black dogfish, witch flounder, red crab, and a few dead octocoral colonies. Several small coral recruits and larger coral and sponge colonies were noted on angular rock blocks. Molluscs and shrimps were seen living associated with coral colonies. Dislodged coral colonies were also observed in between areas of large rock blocks. We transited up a steep cliff covered with a dense assemblage of octocorals and sponges. Here, larger coral colonies appeared to grow under ledges and sponges blanketed the walls, particularly the tops of the overhangs. Sediment composition differed between that under the overhangs and away from the cliff, with frequent dislodged coral colonies. A vertical wall with a wide variety of corals and other invertebrates was observed, including a sponge containing cephalopod (octopus, squid or nautilus) eggs. D2 moved up a steep scarp in a stepping stone pattern, with tops covered with debris and sediment. Numerous large bubblegum corals with shrimp associates were observed, with many of the large colonies containing soft coral at the base. D2 approached the top of the vertical scarp at 808 meters and continued upslope, crossing a soft sediment bottom with scattered rock boulders until the dive concluded at 610 meters.
A bivalve surrounded by cup corals and soft corals are attached to a steep cliff face. A squat lobster is associated with soft coral on the lower left, and a jellyfish swims to the left of the bivalve.
Dive 05 was conducted in Hydrographer Canyon, exploring a section of the western wall from approximately 1,300 to 1,420 meters for deep-sea coral and sponge habitats and other deep-water fauna and to examine canyon geomorphology. At least 12 species of deep-sea coral along with numerous species of associates (shrimps, squat lobsters, isopods, amphipods) on the coral colonies were observed throughout this dive, and a strong current persisted out of the northwest. The Deep Discoverer remotely operated vehicle reached the seafloor at a depth of 1,418 meters. The bottom consisted of large, detached angular sedimentary (compacted mud) blocks draped with bioturbated sediment, suggesting that the sediments had been there for some time. During transit to the first dive waypoint, several species of corals including a black coral were seen, as well as individual small corals indicative of new recruits, and numerous octopods under rock ledges. Transiting up a steep, sediment covered slope towards waypoint 2, a spider crab, white octopus, sea lily, and rat-tail fish were observed. A vertical cliff face was encountered at 1,376 meters covered with at least eight different species of deep-sea corals. We continued to transit over blocky rock outcrops with extensive bioerosion, likely sedimentary mudstone, and extensive coral gardens until a more sedimented slope was crossed. At 1,352 meters, we conducted our final transit to waypoint 3, continuing over a sedimented slope with numerous burrows and xenophyophores, single-celled organisms that can reach at least 10 centimeters in diameter. Another large vertical wall was discovered near the end of the dive with octocorals and cup corals. Numerous columnar structures within and dislodged at the bottom of the wall face were observed, as was a small slope failure.
We had a great dive today with the Deep Discoverer remotely operated vehicle (ROV), discovering active methane seeps and more chemosynthetic communities! The primary purpose of today's dive was to ground truth bubbles plumes in the water column detected by our multibeam sonar in 2012 (and again last night that suggest the presence of gas seeps in the area) as well as characterize diverse habitats that may exist within and outside potential seep areas. The ROV arrived on bottom at 1,475 meters, and began transiting upslope to our first potential seep target. Live and dead mussels in clumps and patches (some cases linear) were seen during transit, and at 1,450 meters a small angular chunk of methane hydrate was identified along with bacterial mats and more clumps of mussels. Sediments with a dark or black stained appearance were common, and at 1,447 meters, a few sparse methane bubbles were seen escaping holes in the seafloor. Continuing further upslope, a large mussel bed was discovered at 1,426 meters. Several patches of raised mussel mounds were conspicuous hosting white filamentous microbes growing on the mussel shells. Few fauna were observed among the mussels, but those present included a single individual of Alvinocaris shrimp and amphipods. A run across the approximately 6x9-meter wide mussel bed was conducted before continuing the dive. At 1,419 meter, we came across active and streaming bubbles emanating from multiple locations. Following a problem with a ship that pulled us off site, we returned to the seafloor and started a transit up slope to the third potential seep target, encountering white stained sediments, carbonate material and small patches of mussels. Finally, at 1,420 meters we discovered rapid and active bubbling. Methane hydrates were identified on the seafloor, and it was questioned whether some of the large patches of white material were hydrates and not bacterial mats. All in all, it was a great dive providing key new information about the utility of exploring bubble plumes from multibeam data, methane hydrate production in North Atlantic canyons, and cold seep communities in the region.
Close-up of methane hydrate observed at a depth of 1,055 meters, near where bubble plumes were detected in previous sonar data. Methane hydrates, a hydrate patch, and chemosynthetic communities were seen during today’s dive, but no active seepage was observed.
The third remotely operated vehicle (ROV) dive of the expedition was conducted today at "New England Seep 3" in approximately 1,100 meters of water. The goal of the dive was to investigate four potential seep sites that were identified based on bubble plumes seen in multibeam sonar data during 2012 Okeanos Explorer mapping operations. ROV Deep Discoverer arrived at the seafloor in an area where the surrounding sediment was mostly silt and silty clays. We moved slightly upslope to the northwest, coming across stained sediment and white sediment (indicative of bacterial mats), along with varying patches of dead mussel shells, shell fragments, and carbonate rubble. Moving further upslope to the Northeast, we encountered carbonate in a line, like a small outcrop ledge associated with dead mussel shells. Turning back to the Northwest, we again encountered more carbonate material; mussels in small clumps; as well as several white, bacterial mats. Methane hydrates were observed at a depth of 1,124 meters, and as we continued upslope, we encountered a medium-sized mussel bed at 1,065 meters, confirming an active chemosynthetic community in this area. Further upslope, we found additional methane hydrates and a hydrate patch at a depth of 1,054 meters in the vicinity of the bubble plumes identified in previous sonar data, although no active seepage was observed during the dive. Common fauna observed along the dive track included an abundance of cutthroat eels, red crabs, eelpout, witch flounder and xenophyophores.
An aggregation of deep sea red crabs prey on what appear to be eggs lying on the seafloor. Large numbers of this commercially important species were imaged during today's dive. The red dots are lasers from the ROV located 10 centimeters apart.
The second remotely operated vehicle dive of the expedition was conducted today between Veatch and Nantucket Canyons, investigating numerous pockmark features on the upper continental slope between 500 and 650 meters above the headwall scarp of a landslide. An enormous aggregation of krill were encountered at the beginning of the dive and remained with the vehicle throughout. The seafloor at this site was covered in silty, soft sediment, and there was no observable difference in the sediment inside or outside the pockmark features. Moving west across the seafloor, we encountered igneous dropstones/glacial erratics throughout the dive and occasional clumps of hard substrates surrounded by scouring. Algal debris, garbage, and ghost fishing gear was often observed. The fishing gear included unrecovered crab traps signifying that fishing is evident in this area. Many red crabs were observed during the entire dive. Noteworthy crab behaviors included mating, preying on midwater fishes, and preying on what appeared to be eggs lying on the seafloor. We also observed Jonah crab, numerous hermit crabs, and occasional squat lobsters in the area. Demersal fishes were also diverse throughout this dive.
NOAA's new deepwater remotely operated vehicle, Deep Discoverer (D2), is deployed off the fantail of the ship for the first dive of the expedition.
The first remotely operated vehicle dive of the expedition was conducted today at a site east of Block Canyon, transiting up a steep slope to investigate headwall scarps of a large landslide scar on the lower continental slope. The dive started at approximately 1,870 meters, transiting over a fairly flat, soft-sedimented bottom toward the base of the slope feature (or headwall scarp). A number of large angular boulders, likely detached from the adjacent vertical walls, and sea spiders, several species of sea pens, and a variety of fishes were encountered. Hardbottom habitats were encountered as we surveyed upslope: two large vertical rock walls with relief of more than 15 meters and separated by a steeply sloped ledge, and several other smaller walls and rock/boulder outcrops. Numerous corals colonized the faces and tops of the large hard features and cup corals were observed attached to the underside of ledges. Brown staining was observed on the rock walls, and in many areas the hard substrates were heavily eroded, with numerous burrows and crevices. Some columnar structures were also observed. The top of this feature at approximately 1,621 meters depth was covered with soft sediment composed of silt and silty clays and was home to few animals except halosaur fish and cutthroat eels. The sessile fauna was dominated by Acanella sp., a type of bamboo coral that commonly occurs on both soft and hard substrates.
The 2013 Northeast U.S. Canyons Expedition Commences!
NOAA Ship Okeanos Explorer departed her homeport in North Kingstown, Rhode Island, today, starting Leg 1 of our Northeast U.S. Canyons Expedition. Crew and mission personnel spent the day preparing to get underway, training new personnel, and preparing systems for operation. The ship spent the day acquiring mapping data during transit to our first remotely operated vehicle (ROV) dive site. Our first ROV dive is planned for tomorrow morning at a site located east of Block Canyon, where we plan to investigate headwall scarps of a large landslide scar on the lower continental slope.
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