Seascape Alaska 5: Gulf of Alaska Remotely Operated Vehicle Exploration and Mapping
(EX2306)
August 23 - September 14, 2023
NOAA Ship Okeanos Explorer
Gulf of Alaska
Map, explore, and characterize ecologically and economically important deepwater habitats in unexplored regions off Alaska
Multibeam sonar, remotely operated vehicles Deep Discoverer and Seirios
Expedition Summary
From August 23 - September 14, NOAA Ocean Exploration and partners conducted the fifth in a series of Seascape Alaska expeditions on NOAA Ship Okeanos Explorer. Operations during this 23-day expedition included 19 successful remotely operated vehicle (ROV) dives conducted in water depths ranging from 253 - 4,262 meters (830 - 13,983 feet), mapping of 28,287 square kilometers (10,922 square miles) of seafloor, and the collection of a wide variety of biological and geological samples. Altogether, data from the Seascape Alaska 5: Gulf of Alaska Remotely Operated Vehicle Exploration and Mapping expedition will contribute to our collective baseline understanding of the ocean, improving our ability to protect and manage marine ecosystems and furthering public awareness of the splendor, importance, and interconnectivity of the ocean to our everyday lives. View full expedition summary.
During the Seascape Alaska 5 expedition, the team navigated challenges ranging from rough weather to poor visibility, and completed 19 deepwater remotely operated vehicles (ROV) dives in the Gulf of Alaska and coastal fjords.
Operational Summary
- Days at sea: 23
- Full ROV dives: 19, ranging in depth from 253 - 4,262 meters (830 - 13,983 feet)
- Biological samples collected: 72 primary samples, 197 associates
- Geological samples collected: 32 primary samples, 13 associates
- Water samples collected for eDNA analysis: 70
- Seafloor area mapped: nearly 28,287 square kilometers (10,922 square miles)
- Science party participants: >50
- Live video views: Approximately 222,000
Images and Videos
Dives
Seascape Alaska 5: Gulf of Alaska Remotely Operated Vehicle Exploration and Mapping included both mapping and remotely operated vehicle (ROV) operations, with video from ROV dives streamed online in real time while the expedition was underway.
The list below provides information about dives that took place during the expedition. Click on a dive name to find its location on the map and access a link to related image and video highlights. Links to final dive data and summaries will be added when available, after the expedition.
Dive 01: Kodiak Slope
Date: August 24, 2023
Location: Lat: 55.930537°, Long: -152.918504°
Dive depth range: 2,910 - 3,099 meters (9,547 - 10,168 feet)
We started the Seascape Alaska 5 expedition with a dive to a previously unexplored area off the coast of Kodiak, Alaska, which showed potential of being the site of a marine landslide. The remotely operated vehicle dove to approximately 3,099 meters (9,547 feet) before starting a course upwards along a slope. The sediment in this area was very soft and barely consolidated. Outcrops had higher levels of sedimentation in shallower depths than in deeper depths, which was opposite of what was expected. A wide array of organisms were observed throughout the dive, with a high level of diversity of cnidarians and echinoderms. Organisms observed included corals, sponges, anemones, brittle stars, sea stars, crinoids, sea cucumbers, squat lobsters, fish, and urchins. One geology sample and three biology samples were collected while on the seafloor and water samples were collected at depths of 3,000; 2,250; 1,500; 750; and 350 meters (9,843; 7,382; 4,921; 2,461; and 1,148 feet).
Dive 02: Kodiak Seep
Date: August 25, 2023
Location: Lat: 56.922611°, Long: -149.556463°
Dive depth range: 4,253 - 4,262 meters (13,952 - 13,981 feet)
The second dive of the Seascape Alaska 5 expedition was a dive to a potential cold seep off the coast of Kodiak, Alaska. The dive track followed a flat soft sediment bottom. While we did not find any seeps or chemosynthetic communities, we saw some interesting biology including large fish, yellow sea urchins, and various sea cucumbers. Several different species of sea pen (Order Pennatulacea) were seen in relative abundance, as well as giant grenadier (Albatrossia pectoralis), and two rare sea urchins, one of which had a very unusual pyramid shape (Echinocrepis sp.).
Dive 03: Giacomini Seamount
Date: August 26, 2023
Location: Lat: 56.492249°, Long: -146.311728°
Dive depth range: 733 - 898 meters (2,405 - 2,946 feet)
The third dive of the Seascape Alaska 5 expedition was a dive to Giacomini Seamount in the Gulf of Alaska. The geology of the seamount changed as the remotely operated vehicle progressed to its peak, transitioning from well-exposed volcanic outcrops on the summit flanks and ascending to the summit plateau where we encountered pebbly sands and rounded boulders that may represent ancient nearshore deposits. There was an abundance of biological diversity throughout the dive, with organisms present on all parts of the seamount that were explored. Some of the biological highlights were a large bubblegum coral (Paragorgia arborea), many different species of glass sponges (class Hexactinellida), fields of tentacled bamboo coral (Isidella tentaculum), and a rare nine-armed sea star (Asthenactis sp.).
Dive 04: Quinn Seamount
Date: August 27, 2023
Location: Lat: 56.354119°, Long: -145.137218°
Dive depth range: 1,838 - 2,023 meters (6,030 - 6.637 feet)
The fourth dive of the Seascape Alaska 5 expedition took place at Quinn Seamount, a volcano in the Kodiak-Bowie seamount chain that had not previously been explored. The geology of the seamount featured mostly well-exposed volcanic outcrops as well as some rocks covered in ferromanganese crust. We were able to take some very rare biological samples, highlighted by a mushroom coral in the genus Anthomastus that is believed by experts to be a new species to science. Many grooved Tanner crabs (Chionoecetes tanneri) at various life stages were also seen, with one juvenile observed hitching a ride on a sea cucumber.
Dive 05: Surveyor Seamount
Date: August 28, 2023
Location: Lat: 56.086274°, Long: -144.305897°
Dive depth range: 381-644 meters (1,250 - 2,113 feet)
The fifth dive of the Seascape Alaska 5 expedition took place at Surveyor Seamount, a volcano in the Kodiak-Bowie seamount chain that had not previously been explored. After completing overnight mapping, the team decided to dive on one of three roughly cone-shaped mounds perched on the seamount’s summit plateau that were revealed by the new mapping data collected the night before. From the summit plateau, we ascended a ridge likely underlain by a basalt dike to the summit of the cone, about 280 meters (918 feet) higher. During the first half of the dive, near the oxygen minimum zone, we observed astonishing numbers of brittle stars which covered nearly every surface. As the remotely operated vehicle ascended above the oxygen minimum zone, we saw the brittle star mats replaced by encrusting sponges (class Demospongiae).
Dive 06: Durgin Guyot
Date: August 29, 2023
Location: Lat: 55.807396°, Long: -141.751005°
Dive depth range: 1,003 - 1,270 meters (3,291 - 4,167 feet)
During the sixth dive of the Seascape Alaska 5 expedition, we explored Durgin Guyot, a volcano in the Kodiak-Bowie seamount chain that had not previously been explored. The remotely operated vehicle ascended a ridge exhibiting beautiful volcanic flow features and collected basalt samples for geochemical and geochronologic studies. The biology throughout the dive was consistently sparse with the occasional sponge and coral. We were able to sample a brittle star (class Ophiuroidea) of particular interest, as well as a unique and unknown stalked glass sponge (class Hexactinellida). Perhaps the most interesting thing about this particular dive were the indications of how the area had changed: there were perhaps hundreds of hollow bases of dead glass sponges, indicating that at one point they dominated the area.
Dive 07: Deep Discoverer Dome
Date: August 30, 2023
Location: Lat: 55.011748°, Long: -140.834551°
Dive depth range: 3,171 - 3,290 meters (10,403 - 10,794 feet)
The seventh dive of the Seascape Alaska 5 expedition was a dive to what the team dubbed “Deep Discover Dome,” a volcano in the Kodiak-Bowie seamount chain that had not previously been explored. We started at a depth of 3,290 meters (10,794 feet) before we ascended a small volcanic vent. The dive provided a rare glimpse into the abyssal depths as we saw the shift from a highly sedimented area to rocky outcrop. We documented an incredibly abundant glass sponge (class Hexactinellida, likely in the genus Atlantisella), a high diversity of crinoids (class Crinoidea), and an as-of-yet completely unidentified gold-colored specimen for detailed study.
Dive 08: Denson Seamount
Date: August 31, 2023
Location: Lat: 54.135633°, Long: -137.384965°
Dive depth range: 1,272 - 1,458 meters (4,173 - 4,783 feet )
The eighth dive of the Seascape Alaska 5 expedition was to explore Denson Seamount, on a volcano in the Kodiak-Bowie seamount chain that had not previously been explored. We began on the upper flank of the seamount and ascended to the summit, sampling the basaltic rocks for chemical and age studies, and then we explored the summit plateau. The dive showcased a wide variety of glass sponges (class Hexactinellida), as well as our first really abundant demosponge (Poecillastra sp.). There was a high abundance of anemones in the genus Liponema in the deeper half of the dive, as well as lithodid crabs and sea slugs, both seen in possible mating pairs. We were lucky enough to see multiple octopods on this dive, including a small juvenile. The larger octopods displayed bold changes in color as we observed them.
Dive 09: Ernest Sound
Date: September 2, 2023
Location: Lat: 55.966425°, Long: -132.082179°
Dive depth range: 253 - 546 meters (830 - 1,791 feet)
The ninth dive of the Seascape Alaska 5 expedition was a dive to Ernest Sound within the Alexander Archipelago. This was a shallow dive compared to our typical operations, starting at about 546 meters (1,791 feet) depth before ascending a near-vertical rock face of Cretaceous and Jurassic metasedimentary rock. There was a high level of biodiversity, with highlights including large stalks of black coral (Bathypathes alaskensis), a great abundance of brachiopods, and multiple giant Pacific octopods (Enteroctopus dofleini).
Dive 10: Behm Canal
Date: September 3, 2023
Location: Lat: 55.225158°, Long: -131.084839°
Dive depth range: 375 - 578 meters (1,230 - 1,896 feet)
The tenth dive of the Seascape Alaska 5 expedition was a dive to Behm Canal, an area within the Alexander Archipelago. The dive track ascended a near-vertical rocky face of Cretaceous and Jurassic metasedimentary rock. Juvenile red tree coral (Primnoa pacific) were seen in areas both near the base and higher up the wall, indicating some recruitment is present in this high-current area. A beautiful white Paragorgia coral (stephencairnsi species complex) was also observed, and scientists were able to take samples for morphological and genetic analysis. Scientists were also able to collect an unknown species of sea star in the genus Cheiraster, which will be used to fill in important information in existing identification guides.
Dive 11: Cordova Bay
Date: September 4, 2023
Location: Lat: 54.724357°, Long: -132.537116°
Dive depth range: 310 - 485 meters (1,017 - 1,591 feet)
The eleventh dive of the Seascape Alaska 5 expedition was a dive to Cordova Bay, an area on the north side of Dixon Entrance. We found an astonishing abundance of red tree corals (Primnoa pacifica) with forests of older, larger corals along the ridges of many of the features we explored, each with a diversity of associates. We saw a variety of fish including various rockfish species (including both juveniles and gravid adults), unusually large nudibranchs, sea stars grazing on the corals, and many squid of various sizes.
Dive 12: Noyes Canyon
Date: September 5, 2023
Location: Lat: 55.033102°, Long: -134.520236°
Dive depth range: 1,452 - 1,635 meters (4,764 - 5,364 feet)
The twelfth dive of the Seascape Alaska 5 expedition took place in Noyes Canyon in the Gulf of Alaska. We began on a seafloor of soft sediment with small rocks heavily colonized by large anemones. Then we ascended the southern canyon wall, finding abundant evidence of recent mass wasting of the canyon walls, likely related to the 2013 earthquake in Craig, Alaska, which had a magnitude of 7.5. In terms of biology, the highlight of the dive was the chance to observe the deep-sea octopus Graneledone boreopacifica. Early in the dive, we observed two females of the species clinging to the same rock, brooding their eggs. This species of octopus has been recorded brooding for over four years, the longest brooding time of any animal on record. We also observed other adult octopods in the area, as well as several small juveniles.
Dive 13: Prinsendam
Date: September 6, 2023
Today’s dive was focused on maritime heritage, with the remotely operated vehicles being deployed on a target that was thought to be the potential remains of the cruiseliner Prinsendam, which sank in 1980 with no loss of life. Unfortunately, on-the-ground footage revealed only the seafloor, leaving the ship’s final resting place a mystery for the time being. While on the seafloor, a few opportunistic benthic observations were made, including sightings of Echinocrepis sp., large holothurians, a pterasterid sea star, and potentially the stalked sponge, Hyalonema sp., before the dive was cut short in order to address an equipment issue.
Dive 14: Chatham Seep
Date: September 7, 2023
Location: Lat: 55.909448°, Long: -135.492874°
Dive depth range: 696 - 735 meters (2,283 - 2,411 feet)
Dive 14 of the Seascape Alaska 5 Expedition was on the Chatham seep offshore of Chatham Strait in southeastern Alaska. Overnight mapping revealed two main bubble plumes in the water column, apparently emanating from two parallel, linear vents (or alignments of vents) spaced about 150 meters (492 feet) apart and about 1 kilometer (3,280 feet) in length. We were able to explore both seep alignments and found abundant methane seepage. Thick accumulations (more than 10 meters/33 feet) of authigenic carbonate marked the vent areas, with the larger vent topped by a fracture from which a variety of intermittent, sheet-like bubble streams emanated. The communities associated with the seep sites and those on the seep periphery were exceptionally abundant and diverse. Vesicomyid clams, bacterial mats, gastropods, and occasional tubeworms were all seen in close proximity to methane bubbling. Sablefish (Anoplopoma fimbria) were seen in high numbers throughout most of the dive, and some areas were completely covered in encrusting sponges of many different taxa. Rockfish, cladorhizid sponges, bubblegum corals, and benthopectinid sea stars were also seen in localized areas throughout the dive.
Dive 15: Middleton Canyon
Date: September 10, 2023
Location: Lat: 59.248402°, Long: -145.715953°
Dive depth range: 2,010 - 2,220 meters (6,594 - 7,283 feet)
Dive 15 of the Seascape Alaska 5 expedition took place at Middleton Canyon, offshore of Prince William Sound. During this dive we explored an area at the intersection of the Aleutian Subduction Zone and the Yakutat Terrane where we saw potential evidence of the deadly 1964 Alaskan earthquake, which at a magnitude of 9.2, remains the most powerful recorded earthquake in North America, and one of the largest recorded worldwide. During the dive we also observed diverse biology with large stands of bamboo and primnoid corals, anemones, and a branched glass sponge that could be a new species to science, all associated with hard rock and mudstone outcrops.
Dives 16/17: Storey Island
Date: September 11, 2023
Location: Lat: 60.760182°, Long: -147.372269°
Dive depth range: 358 - 396 meters (1,175 - 1,299 feet)
The sixteenth and seventeenth dives of the Seascape Alaska 5 expedition took place in Prince William Sound. The first dive of the day (Dive 16) was cut short by poor visibility on the seafloor, but the team was able to retrieve the vehicles and move to clearer waters northeast of Storey Island to complete Dive 17. This truncated dive provided an interesting look at the soft bottom of Prince William Sound, with several different species of fish (including sablefish, eulachon or candlefish, and halibut). Every exposed rock revealed interesting fauna, including zoanthids, brachiopods, and a giant Pacific octopus.
Dive 18: Gumby Ridge
Date: September 12, 2023
Location: Lat: 59.074711°, Long: -147.012859°
Dive depth range: 1,750 - 1,850 meters (5,741 - 6,070 feet)
Dive 18 of the Seascape Alaska 5 expedition took place at what was dubbed “Gumby Ridge” on the eastern end of the accretionary complex of the Aleutian Subduction Zone. The dive provided a glimpse of a stunning and diverse ecosystem. We landed very close to a small field of sea pens (Balticina sp.) with associated snake stars (Asteronyx loveni), which we continued to see in increasing abundance on and off throughout the dive. As we ascended, we saw diverse and abundant corals and sponges (including bamboo corals, bubblegum corals, and several different species of glass sponges) attached to harder substrate, and close to 20 individual deep-sea octopods (Graneledone boreopacifica) brooding their eggs. We also saw several juvenile deep-sea octopods, a second indication of a successful nursery ground for this rare species, and an incredibly active one at that.
Dive 19: Lone Island
Date: September 13, 2023
Location: Lat: 60.702022°, Long: -147.698393°
Dive depth range: 477 - 645 meters (1,565 - 2,116 feet)
During the nineteenth dive of the Seascape Alaska 5 expedition, we explored rocky outcrops near Lone Island in the Knight Island Passage of Prince William Sound. The soft sediment provided habitat for multiple fish species such as northern smooth tongue, halibut, poacher, arrowtooth flounder, sculpins, and rockfish. The rocky features we saw were generally completely covered with zoanthid anemones, and we also saw a variety of sea slugs and nudibranchs, as well as abundant cup corals and sponges. While we didn’t record any obvious visible evidence of oil from the 1989 Exxon Valdez oil spill, suspected oil residue was discovered on one of the geology samples.
Education Content
Education theme pages provide the best of what the NOAA Ocean Exploration website has to offer to support educators in the classroom during this expedition. Each theme page includes expedition features, lessons, multimedia, career information, and associated past expeditions.
Exploration Team
Naming every participant in a telepresence-enabled expedition is next to impossible, as scientists from around the world have provided input into the expedition plan. However, we've assembled information about the members of the team who are sailing on the ship and participating in the expedition from sea – meet the team!
Related Links
Expeditions
- 2023 Seascape Alaska Expeditions (EX2302-EX2308)
- NOAA Ship Okeanos Explorer: 2023 Expeditions Overview
- Introducing Seascape Alaska
Technology
Media Contacts
Emily Crum
Communication Specialist
NOAA Ocean Exploration
ocean-explore-comms@noaa.gov
Keeley Belva
Public Affairs Officer
NOAA Office of Marine and Aviation Operations
keeley.belva@noaa.gov
For more information, visit the Media Resources page.
NOAA Ocean Exploration’s 2023 Seascape Alaska expeditions will contribute to the National Strategy for Exploring, Mapping, and Characterizing the United States Exclusive Economic Zone, Seabed 2030, and multipartner Seascape Alaska campaign, which has been endorsed by the Intergovernmental Oceanographic Commission of UNESCO as part of the United Nations Decade of Ocean Science for Sustainable Development 2021-2030.
Data collected during all expeditions will be available in NOAA’s public data archives within 90-120 days of its completion and will be accessible via the NOAA Ocean Exploration Data Atlas.
Published August 17, 2023
Last updated January 22, 2024
