Mountains in the Deep: Exploring the Central Pacific Basin






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The Mission Team of the NOAA Ship Okeanos Explorer expedition, Mountains in the Deep: Exploring the Central Pacific Basin. We journeyed from American Samoa through the Cook Islands, Jarvis Island, Palmyra Atoll, Kingman Reef, and the High Seas all the way to Honolulu, HI.

The Mission Team of the NOAA Ship Okeanos Explorer expedition, Mountains in the Deep: Exploring the Central Pacific Basin. We journeyed from American Samoa through the Cook Islands, Jarvis Island, Palmyra Atoll, Kingman Reef, and the High Seas all the way to Honolulu, Hawaii. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
May 19, 2017

Arrival in Honolulu

NOAA Ship Okeanos Explorer pulled into port on Ford Island in Honolulu, Hawaii, today. We finished our remaining tasks and got packed. After 23 days, we are sad to leave this amazing and successful mission. We made some of the first deepwater scientific observations on several seamounts, acquired a foundation of mapping data that provides better insight into the Central Pacific Basin, saw richly biodiverse high-density coral communities, imaged hundreds of different deepwater and midwater species, witnessed unusual animal behaviors, tried new (for us!) methods of engaging with the public, and collected samples that will teach us even more about this area.

The ship will transfer to dry dock in just a few days. This hardworking crew has been going nonstop since January. They will be getting some well-deserved shore leave soon. Our next expedition begins on July 6. We look forward to sharing our work with you this summer!


 


 

 

 

Seamount we mapped on the return voyage to Honolulu. This Mountain in the Deep rose approximately 3,000 meters (9,840 feet) from the sea floor - a fitting end to this spectacular journey!

Seamount we mapped on the return voyage to Honolulu. This "Mountain in the Deep" rose approximately 3,000 meters (9,840 feet) from the seafloor – a fitting end to this spectacular journey! Click image for credit and larger view.

The last sunset during the Mountains in the Deep: Exploring the Central Pacific Basin expedition aboard NOAA Ship Okeanos Explorer.

The last sunset during the Mountains in the Deep: Exploring the Central Pacific Basin expedition aboard NOAA Ship Okeanos Explorer. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
May 17 -18, 2017

Still in Transit

NOAA Ship Okeanos Explorer continued to head towards Honolulu, Hawaii. We persevered through challenging weather conditions – gusting wind and big seas for several days. Our mapping team continues to collect data. Building upon our previous data, our track line going north to Honolulu is adjacent to our previous track line from our southbound expedition in January. By collecting data over unmapped areas, we expand our knowledge about the Central Pacific Basin. On the night of May 17, we went directly over a seamount that rose up ~3,000 meters (9,840 feet) from the abyssal plain. A true "Mountain in the Deep," the peak sat at ~2,500 meters (8,200 feet) depth. Finally, on May 18, we woke up to beautiful, calm day. We hosted our second Facebook Live event with our Mapping and Remotely Operated Vehicle Teams. Again, we received some great questions from our Facebook followers. We aslo conducted multibeam testing to help ensure optimal performance for future expeditions. All of our teams had a lot to do in preparation for arriving in port tomorrow. We are also getting organized for dry dock.


 


 

 

 

Geology Lead Scientist, Dr. Del Bohnenstiehl (left), and Biology Science Lead, Dr. Scott France (middle), answer questions during the first-ever NOAA Ship Okeanos Explorer Facebook Live interaction. Web coordinator, Amy Bowman (right) helped field questions from the public during this exchange.

Geology Lead Scientist, Dr. Del Bohnenstiehl (left), and Biology Science Lead, Dr. Scott France (middle), answer questions during the first-ever NOAA Ship Okeanos Explorer live Facebook interaction. Web coordinator, Amy Bowman (right) helped field questions from the public during this exchange. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
May 16, 2017

Facebook Live

Today, we continued our long journey back to Honolulu. As we transit, we continue to collect multibeam, single beam, backscatter, and sub-bottom data. The mission team worked on summary reports, data quality checks, final production of highlight videos, and coordination with shore for final field identifications of some of the more unusual fauna observed during this cruise. We also continued to prepare for dry dock and for the rest of the cruises this year. Since we weren’t diving, we decided to try out a new form of outreach. We hosted our first-ever live Facebook event! Science team leads Dr. Scott France and Dr. Del Bohnenstiehl answered rapid-fire questions from the public during the event. We had some interesting and thought-provoking questions, with the event receiving over 3,000 views.


 


 

 

 

Photo of a rainbow from NOAA Ship Okeanos Explorer.

Photo of a rainbow, viewed from NOAA Ship Okeanos Explorer. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
May 15, 2017

Transit to Honolulu

Conditions did not improve overnight. Unfortunately, we were unable to dive today. After a very successful mission of exploring the Central Pacific Basin, NOAA Ship Okeanos Explorer has begun transiting to Honolulu. We are conducting mapping operations during this journey. Despite the rolling seas, we are all still hard at work going through our data and reviewing our findings. The team has begun working on end-of-cruise reports and making preparations for dry dock, which will begin a couple days after we return to port.


 


 

 

 

The Mountains in the Deep expedition crew wish all of the mothers out there a very happy Mother’s Day!

The Mountains in the Deep expedition crew wish all of the mothers out there a very happy Mother's Day! Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
May 14, 2017

Happy Mother's Day!

The remotely operated vehicles on NOAA Ship Okeanos Explorer could not be deployed today due to weather conditions. Since we weren't diving, we spent the time mapping the seafloor. The mapping team was hard at work all night and all day. The rest of the team took an opportunity to get organized, enter data, crunch numbers, and analyze our progress so far. We are heading north and looking for better conditions so we can dive again tomorrow.


 


 

 

 

We saw several growth stages of the sea pen, Umbellula, anchored in sediment patches. This one is a young colony.

We saw several growth stages of the sea pen, Umbellula, anchored in sediment patches. This one is a young colony. Click image for credit and larger view.

We found this snail on a crinoid - notice the snail’s extended proboscis reaching into the upper surface of the crinoid calyx.

We found this snail on a crinoid – notice the snail's extended proboscis reaching into the upper surface of the crinoid calyx. Click image for credit and larger view.

Pair of amphipods “fishing” from their perch on a red stalked crinoid.

Pair of amphipods "fishing" from their perch on a red stalked crinoid. Click image for credit and larger view.

Hydromedusae jellyfish found in the water column.

Hydromedusae jellyfish found in the water column. Click image for credit and larger view.

video Watch video of snails seen on crinoids.

 


NOAA Ship Okeanos Explorer
May 13, 2017

Dive 12: Kingman Deep

Today's dive at Kingman Deep took us to approximately 2,250 meters (7,380 feet). We enjoyed seeing some interesting animals in the water column on the descent, and highlights included some beautiful jellyfish, ctenophores, siphonophores, shrimp, and ray-finned fishes. When we arrived on bottom, the substrate composition was ferro-manganese (Fe-Mn) crusted volcanic rocks, with soft sediment in between. We observed chrysogorgiid corals with ophiuroids (brittle stars) wrapped in their branches. Different species of ophiuroids crawled along the seafloor, and we observed what may have been a Pteraster slime star, a sea pen, black coral, bamboo coral, brisingid sea star, and a carnivorous sponge.

As we headed upslope, we saw a stalked crinoid that – oddly, we thought – had a relatively large snail crawling on its underside. A close-up view showed the snail appeared to be feeding on the crinoid using a greatly extended proboscis. We encountered more sea pens, sponges, ophiuroids, brisingids, and bamboo coral and made first sightings of corallimorphs, holothurians (sea cucumbers), acorn worms, bryzoans, anemones, shrimp, squat lobsters, tunicates, urchins, a venus flytrap anemone, and cup corals. We came upon another stalked crinoid with a snail on its underside – then we found several more crinoids with snails. Some snails had their proboscis out and appeared to be feeding, others were laying eggs on the crinoids! We observed several bubblegum corals overgrown with yellow zoanthids and clung to by ophiuroids, and a pair of amphipods perched on a red stalked crinoid. Fish highlights included a rattail and a halosaur.

We conducted midwater transects on the way back to the surface at 1,500 meters (4,920 feet), 1,200 meters (3,935 feet), the oxygen minimum zone at 600 meters (1,970 feet), and the peak scattering layer at 300 meters (985 feet). We saw copepods, chaetognaths, jellyfish, shrimp, siphonophores, a dragonfish with a very long bioluminescent lure, and several hatchetfish. One unusual jellyfish had rigid protrusions that made it look like a carnival tent.


 


 

 

 

ROV Deep Discoverer on the bottom at Kingman Cone. The seafloor was manganese-encrusted carbonate with soft sediment between boulders and rock debris.

ROV Deep Discoverer on the bottom at Kingman Cone. The seafloor was manganese-encrusted carbonate with soft sediment between boulders and rock debris. Click image for credit and larger view.

Venus flytrap anemone perched on a bamboo coral at Kingman Cone.

Venus flytrap anemone perched on a bamboo coral at Kingman Cone. Click image for credit and larger view.

We were able to get some close-up imagery of this smalltooth sand tiger shark at ~1,025 meters (~3,360 feet) of depth on Kingman Cone.

We were able to get some close-up imagery of this smalltooth sand tiger shark at ~1,025 meters (~3,360 feet) of depth on Kingman Cone. Click image for credit and larger view.

video Watch video of the smalltooth sand tiger shark.

 


NOAA Ship Okeanos Explorer
May 12, 2017

Dive 11: Kingman Cone

Today's dive was conducted on a conical feature along the eastern slope of Kingman Reef. During descent we saw a dumbo octopus, which is always exciting on Octopus Friday! The seafloor throughout the dive was manganese-encrusted carbonate with several large boulders and a few unusually weathered features. Soft sediment was between the boulders and rock debris. As the vehicles reached the seafloor, we observed a ray-finned fish called a halosaur at about 1,030 meters (3,400 feet) of depth. While enjoying our approximately three hours of bottom time, we observed rock pens, several different types of urchins, sea stars, anemones, acorn worms, hydroids, a diversity of octocorals, black corals, brittle stars, sponges, shrimp, and squat lobsters. Several of the corals observed were very large, and we documented one high-diversity, high-density community. We also saw several fishes, including oreo dories, rattails, and a hatchet fish. A favorite observation of many today was the smalltooth sand tiger shark. Unfortunately, the remotely operated vehicle tether got a loop in it that jeopardized the safety of the vehicles and we had to recover early.


 


 

 

 

Urchins were common on Dive 11 at Kingman Reef.

Urchins were common on Dive 11 at Kingman Reef. Click image for credit and larger view.

During the early planning stage of the expedition, we received a request to help resupply the field station at Palmyra Atoll, as supplies are hard to come by on this remote atoll. Pictured here was an exciting encounter with a dolphin during our small boat transfer of supplies.

During the early planning stage of the expedition, we received a request to help resupply the field station at Palmyra Atoll, as supplies are hard to come by on this remote atoll. Pictured here was an exciting encounter with a dolphin during our small boat transfer of supplies. Click image for credit and larger view.

A shrimp came out of a hole when Deep Discoverer arrived on the bottom.

A shrimp came out of a hole when Deep Discoverer arrived on the bottom. Click image for credit and larger view.

video Watch video of a coffinfish seen at the end of the dive.

 


NOAA Ship Okeanos Explorer
May 11, 2017

Dive 10: South Palmyra Slope

The midwater fauna today was very different from the other areas we have explored on this expedition. The acoustically detected layer of animals in the water column was closer to the surface and did not extend to the seafloor, but was thick with animals. The near-surface layer was filled with salps – colonial gelatinous tunicates that can form very long chains. On the descent, we saw a lot of fish from 200-250 meters (655-820 feet). Below that, we saw a mix of chaetognaths (arrow worms), fishes, various crustaceans, ctenophores (comb jellies), and a lot of siphonophores (colonial jellyfish) before we made our way to the seafloor.

Remotely operated vehicle Deep Discoverer (D2) began the dive on a steep, carbonate slope at approximately 500 meters (~1,640 feet). Initial observations in this area included a shrimp, a glass sponge with a brittle star hiding in it, a primnoid coral with hermit crabs and a squat lobster, and a brief visit from a bristlemouth fish. As we continued upslope, D2 encountered a snake eel; a corallamorph; and a host of echinoderms – sea stars, urchins, and holothurians (sea cucumbers). As we moved along the track, a rattail came over and we noticed ripples in the sediment before sighting black coral. Other highlights in this area were brightly colored anemones, a scorpionfish, a spikefish, an oreo dory, and a zoanthid-covered bubblegum coral that was host to brittle stars and a squat lobster.

Getting a closer look at the sand, there appeared to be the remnants of a calcareous algae (Halimeda sp.) common in the Pacific at shallower depths. Further upslope, we saw more primnoid corals, bubblegum corals, glass sponges, anemones, and echinoderms. We also found a benthic ctenophore (comb jelly) clinging to a dead coral. We encountered a gold-spotted duckbill fish, a common Pacific fish, as well as a type of flatfish, probably a Samaridae. Another eel swam cautiously by D2’s bright lights. We found several urchins clustered together near a small splendid perch while a brittle star meandered towards a bright blue octocoral. Just before we started our return to the surface, we saw a chaunax (sometimes called a coffinfish or toadfish) on the wall. During the transit back up from the seafloor we again saw a lot of fish, but they seemed to be a different species than those we saw on the way down. The high abundance of salps and fishes here is indicative of high productivity in the area, because both need a significant amount of food to thrive in high numbers.


 


 

 

 

This corallimorph was found at “West Palmyra Seamount” at approximately ~2,170 meters (7,120 feet) depth. Notice the white tips of its tentacles.

This corallimorph was found at "West Palmyra Seamount" at approximately ~2,170 meters (7,120 feet) depth. Notice the white tips of its tentacles. Click image for credit and larger view.

Brittle stars clung to this zoanthid-covered bubblegum coral.

Brittle stars clung to this zoanthid-covered bubblegum coral. Click image for credit and larger view.

This sea star (Solasteridae Lophaster sp.) was found feeding on a crinoid.

This sea star (Solasteridae Lophaster sp.) was found feeding on a crinoid. Click image for credit and larger view.

video Watch video of the sea star feeding on the crinoid.

 


NOAA Ship Okeanos Explorer
May 10, 2017

Dive 09: "West Palmyra Seamount"

Today we sent the remotel operated vehicles (ROVs) Seirios and Deep Discoverer to ~2,170 meters (~7,120 feet) deep on a site we called "West Palmyra Seamount." The bottom composition was mostly ferro-manganese (Fe-Mn) rock with some soft, light-colored sediment filling the spaces in between. We were greeted immediately by several small anemones attached to a large boulder with tentacles swaying in the current. Nearby were a corallimorph, a stalked sponge, a crinoid, and a black coral with near-perfect symmetry. As we moved along our dive track, we continued to find interesting organisms. Brittle stars clung to a bubblegum coral overgrown with zoanthids, and a rock pen gripped tenaciously to a Fe-Mn rock. Up ahead, two species of holothurians (sea cucumbers) feasted on sediment. Ripples in the sediment indicated currents in the area. Here, sea pens emerged from the sediment while tunicates and sponges were attached to the rocks. A shrimp scurried away from the lights of the ROVs – but not before we noted it for National Shrimp Day!

More crinoids, brittle stars, black corals, chrysogorgiids, and sea pens appeared. We saw urchins, polychaetes, a solitary hydroid, a carnivorous sponge, and a sea star feeding upon a crinoid. A shrimp and a cluster of barnacles were on a large rock. We found what appeared to be an octopus egg on a black coral while a squat lobster crawled on a different black coral nearby. A six-legged sea star used its tube feet to move slowly on a large Fe-Mn crusted rock. We came upon a bamboo coral whip. At this point in the dive, the wind had picked up considerably and we needed to bring the ROVs back to the surface for safety.


 


 

 

 

A view of the NOAA Ship Okeanos Explorer mapping track, showing some of the “Mountains in the Deep”. The color bar shows the depth of these features.

A view of the NOAA Ship Okeanos Explorer mapping track, showing some of the "Mountains in the Deep." The color bar shows the depth of these features. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
May 9, 2017

Mapping to Palmyra

NOAA Ship Okeanos Explorer spent the day mapping during our transit to the Palmyra Atoll/Kingman Reef Unit of the Pacific Remote Islands Marine National Monument. We mapped for roughly 300 nautical miles, a testament to the vastness of this region we are exploring. Most of what we saw along this route were abyssal plains. We did, however, map in high resolution the summits of a few smaller seamounts on this track.


 


 

 

 

ROV Deep Discoverer found this ipnops on Dive 08 of the Mountains in the Deep Expedition. Ipnops is a tripod fish with highly modified eyes that lives in deep water.

ROV Deep Discoverer found this ipnops on Dive 08 of the Mountains in the Deep expedition. Ipnops is a tripod fish with highly modified eyes that lives in deep water. Click image for credit and larger view.

ROV Deep Discoverer explores the Clipperton Fracture Zone. This is the deepest dive on the Mountains in the Deep expedition.

ROV Deep Discoverer explores the Clipperton Fracture Zone. This is the deepest dive on the expedition. Click image for credit and larger view.

This Dana octopus squid followed the ROV down for a while. Notice the bioluminescent spotlights on the tips of two of its arms.

This Dana octopus squid followed the ROV down for a while. Notice the bioluminescent spotlights on the tips of two of its arms. Click image for credit and larger view.

video Watch video of a sea cucumber seen during the dive.

 


NOAA Ship Okeanos Explorer
May 8, 2017

Dive 08: Clipperton Fracture Zone

While we've been targeting seamounts for nearly all of the previous dives, today we dove along the far westernmost edge of the Clipperton Fracture Zone. Deep Discoverer (D2) descended to a depth of 4,500 meters (~14,765 feet) – our greatest depth on this expedition. This feature is among the longest tectonic structures on Earth, extending from the Line Islands more than 7,000 kilometers (4,350 miles) east to the Clipperton Transform on the East Pacific Rise – that's further than the distance from Honolulu to Chicago!

It was an exciting descent as we transited through the water column. There was a surprising amount of marine snow and particles throughout the full water column – surprising because typically much of this organic material has been decomposed by bacteria by the time it sinks below ~2,000 meters (~6,560 feet) – the water was relatively clear below that. On the descent, a Dana octopus squid followed us for a while. We saw a layer of fish and siphonophores at mesopelagic depths of 200-1000 meters (660-3,280 feet). From 1,000-1,500 meters (3,280-4,920 feet), we saw chaetognaths, fish, and many large red copepods. We did not see much fauna in the water column below ~1,500 meters (4,920 feet).

When D2 reached maximum depth, we immediately saw several black corals. Not far from the black corals, we saw large aggregations of small sediment-colored spheres or spherules, like those we saw during the Deepwater Exploration of the Marianas expedition. Nearby, sediment feeders had left trails on the seafloor. Other biological highlights were bamboo corals, including the second deepest ever collected; several holothurians (sea cucumbers); bryzoans; anemones; chitons; carnivorous tunicates (sea squirts); brisingid sea stars; crinoids; scale worms (polynoid polychaete); tube-dwelling fanworms (sabellid polychaete); sea stars; a carniverous starburst sponge; shrimp; chimera; and a deep ocean lizardfish with highly reflective eyes.

Because the sun set during our ascent, many of the midwater animals had migrated toward the surface as part of their diel vertical migration. By the time we transited through the water column, a very active layer of jellies, siphonophores, and fish started around 600 meters (1,970 feet) and extended into the epipelagic zone, which extends from 200-1,000 meters (~655-3,280 feet) deep.


 


 

 

 

Female golden crab, heavy with purple eggs, found at about 1,015 meters (3,330 feet) on Dive 07, is covered in black spot disease. The family name, Geryonidae, comes from Geryon of Greek mythology. Geryon was a three-headed, four-winged giant who lived on the island of Erytheia on the far side of the Earth-encircling river named Okeanos. The black patches visible all over the crab's carapace and legs are evidence of a bacterial disease, aptly called black spot. Black spot disease can be more prevalent on crabs that have not molted for some time.

Female golden crab, heavy with purple eggs, found at about 1,015 meters (3,330 feet) on Dive 07, is covered in black spot disease. The family name, Geryonidae, comes from Geryon of Greek mythology. Geryon was a three-headed, four-winged giant who lived on the island of Erytheia on the far side of the Earth-encircling river named Okeanos. The black patches visible all over the crab's carapace and legs are evidence of a bacterial disease, aptly called black spot. Black spot disease can be more prevalent on crabs that have not molted for some time. Click image for credit and larger view.

Batfish were common on the seamount dubbed “Whaley”.

Batfish were common on the seamount dubbed "Whaley." Click image for credit and larger view.

This Pacific sleeper shark, seen at about 980 meters (3,215 feet) on Dive 07, came by to inspect the lights from ROV Deep Discoverer.

This Pacific sleeper shark, seen at about 980 meters (3,215 feet) on Dive 07, came by to inspect the lights from remotely operated vehicle Deep Discoverer. Click image for credit and larger view.

video Watch video of a hatchetfish seen during the dive.

 


NOAA Ship Okeanos Explorer
May 7, 2017

Dive 07: "Whaley"

Dive 07 was conducted on "Whaley" seamount, which rises about 3,700 meters (~12,140 feet) above the seafloor – over 20 times as high as the Seattle Space Needle – and has several small cones protruding from an otherwise flat summit. On this dive, remotely operated vehicle Deep Discoverer climbed the most prominent of these cones – traversing from a depth of 1,100 meters (3,610 feet) to its peak near 800 meters (2,625 feet) of depth.

When we reached bottom, we were immediately greeted by a cusk eel and, moments later, a hermit crab that had chosen to take up residence in a long conical shell. The bottom was composed mostly of loose sediment with ferro-manganese (Fe-Mn) rocks and boulders. Most of the biology was found on rock outcrops. Batfish, though typically a rare observation, were quite common at this site. We documented many corals, including gorgian (plexurids) sea fans; several Anthomastus corals – sometimes referred to as mushroom coral; bamboo corals; cup corals; black corals; and even a nephtheid soft coral. Other biological highlights included glass sponges, anemones, crinoids, gastropods, urchins, brittle stars, sea stars, holothurians (sea cucumbers), a burly-armed squat lobster, carrier crabs, shrimp, oreo dories, hatchetfish, a goosefish, and a Pacific sleeper shark.

We also saw some interesting animals in the water column, including more pelagothurians (pelagic sea cucumbers), jellyfish, and a snake mackerel that followed us when we began the dive.


 


 

 

 

We found this sponge attached to a rock in an unusual manner. Notice the base of the sponge looks like it has foot-like appendages.

We found this sponge attached to a rock in an unusual manner. Notice the base of the sponge looks like it has foot-like appendages. Click image for credit and larger view.

This pelagic holothurian, deep sea swimming cucumber,  is unusual in appearance when compared with other sea cucumbers because of its resemblance to a jellyfish. We found this one during our midwater transects about 1,400 meters (4,595 feet) deep, we have seen many so far on this expedition.

This pelagic holothurian, or deep-sea swimming cucumber, is unusual in appearance when compared with other sea cucumbers because of its resemblance to a jellyfish. We found this one during midwater transects at ~1,400 meters (4,595 feet) depth. We have seen many of these sea cucumbers so far on this expedition. Click image for credit and larger view.

We found this hydromedusa, Halicreatis, at about 1,200 meters (3,935 feet) deep. The ends of its tentacles are packed with nematocysts (stinging cells), which make them appear especially bright.

We found this hydromedusa, Halicreatis, at about 1,200 meters (3,935 feet) depth. The ends of its tentacles are packed with nematocysts (stinging cells), which make them appear especially bright. Click image for credit and larger view.

video Watch highlights from the midwater transects.

 


NOAA Ship Okeanos Explorer
May 6, 2017

Dive 06: "Keli'ihananui"

Dive 06 was conducted on a seamount dubbed "Keli'ihananui." This seamount was previously mapped in January 2017 on another NOAA Ship Okeanos Explorer expedition. The seafloor was covered in soft sediment intermingled with outcrops of ferro-manganese (Fe-Mn) encrusted rocks. Because many animals in the deep ocean attach to hard substrate, we saw more animals on or near the rocks than we observed in the sediment. Observations included a pycnogonid (sea spider), anemone, holothurians (sea cucumbers), urchins, a few different octocorals, sea stars, ophiuroids, aplacophorans (a shell-less, benthic, worm-shaped mollusc), crinoids, sponges, a carnivorous sea squirt, shrimp, a gastropod, and a few different fish. Some sponges had attached themselves to the rocks in an unusual manner we had not previously seen: they had several leg-like stalks.

After completing the benthic exploration, we conducted a series of midwater transects from 1,400 to 300 meters (~4,595 to 985 feet). These transects increase our knowledge about one of the least understood biomes on Earth. Fauna observed while surveying the water column were diverse and included: pelagothurian (pelagic sea cucumber), numerous jellyfish species, chaetognaths (arrow worms), midwater fish, ctenophores (comb jellyfish), and multiple species of siphonophores (colonial jellyfish). We were especially excited to see a pyrosome (a colonial tunicate that is long and hollow) that was several meters long – this is a relative of the benthic carnivorous sea squirt we saw.


 


 

 

 

We found this unusual umbrella-shaped pedestal that was covered with corals and sponges towards the end of Dive 05 of the Mountains in the Deep expedition. Zooming in revealed numerous shrimp, crabs, brittle stars, and fish living within this structure.

We found an unusual umbrella-shaped pedestal that was covered with corals and sponges towards the end of Dive 05 of the expedition. Zooming in revealed numerous shrimp, crabs, brittle stars, and fish living within this structure. Click image for credit and larger view.

This sand tiger shark came by to check out ROV Deep Discoverer on Dive 05 of the Mountains in the Deep expedition.

This sand tiger shark came by to check out remotely operated vehicle Deep Discoverer during the fifth dive of the expedition. Click image for credit and larger view.

We saw an octopus for Octopus Friday on Dive 05 of the Mountains in the Deep expedition.

We saw an octopus for "Octopus Friday" on Dive 05 of the expedition. Click image for credit and larger view.

video Watch video of an oreo fish seen during the dive.

 


NOAA Ship Okeanos Explorer
May 5, 2017

Dive 05: Jarvis Island

Today we dove near Jarvis Island, a 4.5 square kilometer (1.7 square mile) uninhabited island just south of the Equator. We investigated a ridge off of the southeast side of the island. From the moment we entered the water until the remotely operated vehicles Seirios and Deep Discoverer (D2) returned to the surface, we were surrounded by rich biodiversity.

On our descent, we observed an exceptionally high number of pelagic animals – indicating that there may be some local upwelling around the island. Midwater fish were abundant, especially around 500-700 meters. We also saw numerous arrow worms, some comb jellies, shrimp, and mysids during the descent. Throughout the dive, we saw some pelagic animals near the seafloor as well, including numerous siphonophores and many pelagic holothurians that appeared to be stuck on seafloor features.

The dive transect crossed several high-density communities including a low-diversity community of scleractinian coral; multiple instances of crinoid, urchin, holothurian, and ophiuroid communities; a landscape of polychaete tube mounds; and fields of primnoid sea fans. The dive closed on an unusual umbrella-shaped pedestal that was densely covered with corals and sponges, with a large school of Randall's snappers nearby. Other highlights of the dive were a sand tiger shark and observing a group of ophiuroids capture and eat a squid.


 


 

 

 

The round purple object on this bubblegum coral is in fact a dumbo octopus
egg. It was seen while exploring at a depth of ~1,630 meters (~5,350 feet) at the seamount dubbed “Kahalewai”. We saw a similar egg on the Discovering the Deep: Exploring Remote Pacific Marine Protected Areas expedition.

The round purple object on this bubblegum coral is a dumbo octopus egg. It was seen while exploring at a depth of ~1,630 meters (~5,350 feet) at the seamount dubbed "Kahalewai." We saw a similar egg on the Discovering the Deep: Exploring Remote Pacific Marine Protected Areas expedition. Click image for credit and larger view.

This giant bamboo coral was seen at close to  ~1,700 meters (~5580 feet) of depth on the seamount dubbed “Kahalewai”. It was about as big as ROV Deep Discoverer. We took a small sample of this coral to learn more about it.

This giant bamboo coral was seen at close to ~1,700 meters (~5,580 feet) depth on the seamount dubbed "Kahalewai." It was about as big as ROV Deep Discoverer. We took a small sample of this coral to learn more about it. Click image for credit and larger view or click here to watch video of the coral.

 


NOAA Ship Okeanos Explorer
May 4, 2017

Dive 04: "Kahalewai"

We had a great dive at a previously unmapped seamount dubbed "Kahalewai." The dive targeted the prominent southern ridge of the seamount at depths between ~1,700 and 1,500 meters (5,580 and 4,920 feet) depth. We saw a variety of midwater animals during the descent, as well as near the seafloor during the dive. These included siphonophores (colonial jellyfish), sergestid shrimp, jellyfish, a Bostigrinus (a carnivorous doliolid or tunicate), pelagothurians (pelagic sea cucumbers), and a squid.

When we reached the bottom, we were treated to a view of a colorful overhang that was populated by low-growing octocorals, encrusting blue sponge, and both gooseneck and acorn barnacles. The ridge feature had pockets of high-density communities that included corals and sponges and barnacles. We observed a number of corals, including an immense yellow colony, a few Iridogorgia, chrysogorgiids, and bubblegum coral. Only a couple of species of fish were recorded: an eel and small elongate rattail. The dominant fauna were crinoids, both feather stars and stalked sea lilies. Many of the stalked crinoids were home to numerous polychaetes, specialized predators of crinoids. Sea pens were abundant in rippled sediment channels set among the exposed rock. Sea urchins were also common and abundant throughout the dive, mainly species with long, curved spines or robust thick spines, but we also saw two species of leather urchins. Other interesting observations included numerous hermit crabs; a chiton leaving feeding traces on rock surfaces; and an aplacophoran, a specialized worm-like mollusc that was feeding on a bamboo coral.

Throughout the dive, a thick ferro-manganese (Fe-Mn) crust was evident, indicating the underlying rock is relatively old. Light-colored sediments were deposited in crevasses and low areas. In some of the larger areas of sediment cover, we observed high densities of sea pens. Ripples in the sediment indicated a dominant flow direction from north to south, consistent with the bottom current conditions reported by the remotely operated vehicle (ROV) pilots. Despite the Fe-Mn crust covering the rock, the ROV imaged collapsed lava tubes and primary volcanic flow (lobate to pillow) structures in some places.


 


 

 

 

A previously unmapped seamount we are calling “Kahalewai”. This seamount has four ridges that radiate outward from the center.

A previously unmapped seamount we are calling "Kahalewai." This seamount has four ridges that radiate outward from the center. Click image for credit and larger view.

This ~4,200 meter (~13,800 foot) high seamount we are calling “Kahalewai” was almost ~1000 meters taller than previously thought.

This ~4,200-meter (~13,800-foot) high seamount we are calling "Kahalewai" was almost 1,000 meters taller than previously thought. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
May 3, 2017

Mapping All the Way

NOAA Ship Okeanos Explorer began mapping operations overnight and continued throughout the day while in transit. This area contains a long stretch of flat abyssal seafloor, which is one of the largest habitats in the world, and we found no major seamounts on our track until we got close to our dive site. Rising from the muddy abyss, an approximately ~4,200-meter (~13,800-foot) seamount was mapped - that is about 11 times the height of the Empire State Building. The unnamed seamount that we are calling "Kahalewai (to read about Carl Kahalewai, click here) has four ridges that radiate outward from the center. This seamount turned out to rise about 1,000 meters (~3,000 feet) higher from the abyssal plain than expected, based on altimetry data. This discovery is another reminder about the importance of high-resolution bathymetric mapping. We have higher-resolution maps of the surface of Mars than we do of the underwater surface of our own planet. Data like these fill in large gaps in our knowledge and give us a better understanding of the world we live in.


 


 

 

 

This cusk eel was found at approximately 2175 meters (7135 ft)on Dive 03 at a site we called “Te Kawhiti o Maui Potiki” during the Mountains in the Deep: Exploring the Central Pacific Basin expedition. There were few fish species at this depth in this location.

This cusk eel was found at approximately 2,175 meters (7,135 feet) during the third dive of the expedition. There were few fish species at this depth in this location. Click image for credit and larger view.

Several different vibrantly colored animals can bee seen in this image, taken at approximately 2240 meters (7350 ft), including an Anthomastus mushroom coral (center), precious pink coral (right), bamboo coral (left), and feather stars (Crinoids).

Several different vibrantly colored animals can be seen in this image, taken at approximately 2,240 meters (7,350 feet), including an Anthomastus mushroom coral (center), precious pink coral (right), bamboo coral (left), and feather stars (crinoids). Click image for credit and larger view.

“Te Kawhiti o Maui Potiki” held a veritable coral forest that extended all the way to the high point of the ridge. Many of the colonies had ophiuroids and crinoids perched in their branches.

"Te Kawhiti o Maui Potiki" held a veritable coral forest that extended all the way to the high point of the ridge. Many of the coral colonies had ophiuroids and crinoids perched in their branches. Click image for credit and larger view.

This pelagic sea cucumber (Holothuria) was seen on a midwater transect at about 1200 meters (3940 feet) during Dive 03 of the Mountains in the Deep: Exploring the Central Pacific Basin expedition. While considered rare , we have been fortunate to see this holothurian during several dives on this year’s CAPSTONE expeditions.

This pelagic sea cucumber (Holothuria) was seen on a midwater transect at about 1,200 meters (3,940 feet) during Dive 03 of the expedition. While considered rare, we have been fortunate to see this holothurian during several dives on this year's CAPSTONE expeditions. Click image for credit and larger view.

video Watch video of the deep-sea coral forests encountered during the dive.

 


NOAA Ship Okeanos Explorer
May 2, 2017

Dive 03: "Te Kawhiti o Maui Potiki"

We had a fantastic dive today on a coral forest along a ridge North of the Manihiki Plateau, at a site we are calling "Te Kawhiti o Maui Potiki." Fifty scientists from around the world joined as we explored this interesting ridge. The ridge feature was previously unmapped, and surprisingly reached 1,000 meters (3,280 feet) closer to the ocean surface than indicated by satellite altimetry.

Remotely operated vehicle (ROV) Deep Discoverer (D2) began on the south side of the ridge and worked upslope before following the ridge crest to the summit. From the moment we touched down on the seafloor, we were surrounded by large bamboo coral colonies. The geology showed mostly in-place outcrop. The rocks were dark in color and covered with ferromanganese (Fe-Mn) crust. Light-colored sediments filled in the low topography between the outcropping rocks. Large corals - some as large D2 or larger - colonized almost every surface. For the duration of the transect (to the shallowest part of the feature), we were in a dense bamboo coral (Isididae) forest, with at least many hundreds, if not thousands, of colonies. Several broken branches and dead coral colonies were seen scattered in areas of live colonies. Most live colonies had crinoids perched on branches (possibly three different species), and on several occasions we encountered upright colonies stripped of tissue and completely covered in crinoids. Other associates included overgrowing zoanthids (at least two species), brittle stars (Ophiacanthidae), and gooseneck barnacles. Along some sections of the ROV path, pillow-like structures were evident in the rocks despite the presence of the Fe-Mn crusts on the surface. Other corals observed included: Octocorals, Anthomastus, a rock pen, at least two species of Chrysogorgidae, Paragorgiidae, at least three additional species of bamboo corals, Corallidae, Iridogorgia, and at least four species of black corals. Sponge observations included a possible new species of glass sponge, carnivorous Cladorhizidae, and several species of glass sponges.

Other biological observations included two species of sea anemone, munidopsid crabs, king crabs, shrimp, hermit crabs with gooseneck barnacles, two species of seastars, sea urchin, chirostylid squat lobsters, and a fourth species of crinoid (on the rock substrate) with 10 arms and tips lacking cirri. Many of the crinoids imaged showed predatory snails attached to the arms. Fish were uncommon, but observations included Antimora, rattail, and cusk eel.

Following the benthic exploration, we made a series of midwater transects. This was the first observation of life in the water column that had ever been completed in this area. We spent 10 minutes at eight different depths ranging from 1,800 to 300 meters. Diversity was high, and we saw numerous siphonophores (colonial jellyfish), chaetognaths (arrowworms), larvaceans (sea tadpoles), ctenophores (comb jellies), and jellyfish throughout much of the water column. Some other interesting fauna that we observed included a pelagic sea cucumber, a pelagic tunicate, and a polychaete worm. We saw a surprising number of fishes, including a snipe eel, several bristlemouths, and a hammerjaw.


 


 

 

 

This saddle-like  feature was mapped on May 1, 2017, between a unnamed seamount and ridge, just north of the Cook Islands. The area was previously unmapped, so this is the first time this feature has ever been revealed to humans in such detail. Data like these are important because they help scientists to understand the importance between ridge areas and plateaus, as well as the connection between this region and others.

This saddle-like feature was mapped on May 1 between a unnamed seamount and ridge, just north of the Cook Islands. The area was previously unmapped, so this is the first time this feature has ever been revealed to humans in such detail. Data like these are important because they help scientists to understand the importance between ridge areas and plateaus, as well as the connection between this region and others. Click image for credit and larger view.

Altimetry data informed us that this ridge feature existed and we selected it as a target for high-resolution bathymetric mapping. Much to our surprise, the ridge turned out to be over a full kilometer higher than previously thought. This is one of the many reasons that high-resolution bathymetry mapping is so important. It allows us to better understand our planet.

Altimetry data informed us that this ridge feature existed and we selected it as a target for high-resolution bathymetric mapping. Much to our surprise, the ridge turned out to be over a full kilometer higher than previously thought. This is one of the many reasons that high-resolution bathymetry mapping is so important — it allows us to better understand our planet. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
May 1, 2017

Back in the Saddle Again

NOAA Ship Okeanos Explorer continued mapping operations today, with special focus on the connection point between two of the prevalent features of region – a ridge and a large seamount. This was a priority area to map, as these data help scientists visualize these seafloor features. Multibeam maps help scientists determine whether connections exist between these features and define the geological origin. We were able to obtain high-quality bathymetric data, as depicted in the top image. After we finished collecting these data, we transited to our next dive site. We then collected additional mapping data along the crest of a ridge that runs parallel to the edge of the Manikiki Plateau. Overnight we will also map our next dive site along this ridge that we are calling Te Kawhiti a Maui Potiki. Data visualizations allow us to pick our dive sites based on fresh bathymetry.


 


 

 

 

Deep Discoverer grabs a manganese-crusted rock sample near a brisingid sea star at about 2400 meters depth during Dive 02 of Mountains in the Deep: Exploring the Central Pacific Basin. The dive site was called Te Tukunga o Fakahotu and was located just north of the Manihiki Plateau, near the Cook Islands.

Deep Discoverer grabs a manganese-crusted rock sample near a brisingid sea star at about 2,400 meters depth during Dive 02 of the expedition. The dive site was called Te Tukunga o Fakahotu and was located just north of the Manihiki Plateau, near the Cook Islands. Click image for credit and larger view.

The Science Team prepares a sample in the wet lab aboard NOAA Ship Okeanos Explorer. This manganese-crusted rock was collected on Dive 02 of Mountains in the Deep: Exploring the Central Pacific Basin.

Members of the on-ship science team prepare a sample in the wet lab aboard NOAA Ship Okeanos Explorer. This manganese-crusted rock was collected during the second dive of the expedition. Click image for credit and larger view.

video Watch video of a snail on move, seen during the dive.

 


NOAA Ship Okeanos Explorer
April 30, 2017

Dive 02: Te Tukunga o Fakahotu

During Dive 02, we explored a rocky, mesa-shaped feature at a site unofficially dubbed "Te Tukunga o Fakahotu," just north of the Manihiki Plateau. This was the first-ever remotely operated vehicle exploration in the area. Beginning at a depth of ~2,480 meters, this dive was nearly seven times as deep as Dive 01. At the start of the dive, the seafloor was composed of black manganese-encrusted rock, which appeared to be volcanic in origin. We collected a rock from this area to be analyzed for composition and age. Light-colored biogenic sediments (likely foram shells) had collected in the areas between these rocks. As we moved along the dive track, we saw an increase in rock rubble. Near the base of a small cliff, we collected another rock sample for further study. Although the density of fauna was fairly low throughout the dive, we saw a large variety of different kinds of animals living at these depths. The most abundant were stalked tunicates, xenophyophores, and brisingid sea stars. Corals included a rock pen, three species of bamboo corals, and a black coral. One bamboo coral had a spiny-armed brittle star (Ophiacanthidae) positioned on a part of the colony lacking tissue; this observation has now been made a number times and begs the question of whether the brittle star causes the loss of tissue or whether it takes advantage of a bare spot on the colony. Representatives of all five echinoderm classes were observed during the dive. At least four species of crinoids (sea lilies and feather stars), four species of sea cucumbers, two species of sea stars (including a slime star), a sea urchin, and one species of brittle star seen on a bamboo coral. Interesting observations included a tumbling Margarita snail and a stalked crinoid with multiple predatory snails feeding on its stalk. When we brought rock samples collected during the dive into the wet lab, we were able to recover some very small organisms from them, including a branching foraminifera; and bryozoans. We also recovered a verrucomorph barnacle, which is asymmetrically developed; this is thought to be a feeding adaptation to the food-poor deep sea that enables these barnacles to catch crawling benthic prey rather than just swimming prey. Surprisingly, not a single fish was seen on the dive, despite the fact that fish often occur in regions of soft sediments because there are often more prey there.


 


 

 

 

This image, from data collected during the CAPSTONE Telepresence Mapping in Pacific Marine Protected Areas expedition shows a seamount that was once volcanically active. The brighter color indicates harder surfaces from more recent activity, while the darker areas indicate sediment that has been deposited between flows.  In addition to being used for scientific interpretations, these images are being used to plan the Jarvis Unit (PRIMNM) dives for our current cruise

This image, from data collected during the CAPSTONE Telepresence Mapping in Pacific Marine Protected Areas expedition, shows a seamount that was once volcanically active. The brighter color indicates harder surfaces from more recent volcanic activity, while the darker areas indicate sediment that has been deposited between volcanic flows. In addition to being used for scientific interpretations, these images are being used for our current cruise to plan dives in the Jarvis Unit of the Pacific Remote Islands Marine National Monument. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
April 29, 2017

Mapping Continues – Back to Backscatter

NOAA Ship Okeanos Explorer continued transiting northeast to our second operating area near the Cook Islands – specifically, just north of the Manihiki Plateau. We continue to map along the way, collecting valuable data in support of Marae Moana, the Cook Islands marine park. While mapping, one of the things we look at is backscatter. In physics, backscatter is the reflection of waves, particles, or signals back to the direction from which they came. For our purposes, it is the sound intensity that returns to the ship's sonars from the seafloor. The reflection of this sound intensity is driven by the acoustical properties of the seafloor surface. Hard surfaces, like rock, tend to return the sonar's sound energy better than softer bottom compositions, like mud. Therefore, measuring the strength of the sound returned from the seafloor can help us interpret what is on the seafloor (e.g., mud, rock, etc.). We can also learn about the roughness of the bottom or grain size. Backscatter data can also assist us with dive planning. Because these data give us an idea of what we can expect to see before we send down the remotely operated vehicle, we can maximize Deep Discoverer's bottom time by targeting the areas we are most interested in exploring.

Tune in tomorrow for our next dive!


 


 

 

 

The NOAA Ship Okeanos Explorer mapping team hard at work in the control room. During the 60+ hours of transit, the ship is continuously collecting data with three different types of sonar.

The NOAA Ship Okeanos Explorer mapping team hard at work in the control room. During the 60+ hours of transit, the ship is continuously collecting data with three different types of sonar. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
April 28, 2017

Mapping Around the Clock

The Okeanos Explorer is transiting northeast from American Samoa to our second operating area along the Northern Manihiki Plateau, near the Northern Cook Islands. During the 60+ hours of transit, the ship is continuously collecting data with three different types of sonar. Today is the first full 24-hour mapping cycle. All systems are working well and we have been able to get started on our mapping products. On these long transits, we cross a lengthy stretch of ocean and are able to collect a continuous record of midwater backscatter data, seafloor bathymetry, seafloor backscatter and upper sediment structure using the three types of sonar on board. Backscatter is defined as the sound intensity that is returned to the ship's sonars and bathymetry is a measurement of depth that tells us what the seafloor looks like, similar to what topography tells us on land. Learn more about the ship's sonar capability and how we map the seafloor here.

Mapping operations on the high seas are incredibly important. These areas are largely unmapped and poorly understood. These new data will provide insights into the structure of the oceanic water column and geology of the seafloor that cannot be gleaned using other mapping platforms, such as satellites. In order to maximize the impact of our mapping operations, we set the trackline (the path the ship will follow) to complement previously mapped areas by matching the edges of existing sonar coverage - this way we add new information to existing datasets and continue to build on the seafloor imagery for the area. Most of the track we have followed today has been deep, muddy abyssal plain greater than 5,000 meters, but we've also been able to map the tops of a few seamounts. While flat muddy seafloor may not be as alluring as seamounts, this is the largest habitat on Earth! At approximately 8:30 pm SST (3:30 am EDT), we came upon one of the day's highlights: a partially mapped volcanic ridge.


 


 

 

 

ROV Deep Discoverer observes a cliff that marks the edge of a coral platform in American Samoa. Fine sediments derived from the coral platform above accented the grooved channels down the steep slope face.

ROV Deep Discoverer observes a cliff that marks the edge of a coral platform in American Samoa. Fine sediments derived from the coral platform above accented the grooved channels down the steep slope face. Click image for credit and larger view.

A chirostylid crab, a type of squat lobster, was seen crawling on a gorgonian seafan (possibly Paracis sp.). In the upper right you can see the coiled arms of an ophiuroid (brittle star) wrapped around the seafan branches. Deep-sea corals provide habitat for many other animals.

A chirostylid crab, a type of squat lobster, was seen crawling on a gorgonian seafan (possibly Paracis sp.). In the upper right you can see the coiled arms of an ophiuroid (brittle star) wrapped around the seafan branches. Deep-sea corals provide habitat for many other animals. Click image for credit and larger view.

This colorful Cephalopholis grouper (also called a garish hind, goldbar grouper, garish rockcod, or Japanese cod - although it is not related to cods) was seen towards the end of Dive 01 of Mountains in the Deep at the Aunuʻu Unit of National Marine Sanctuary of American Samoa. The red dots are lasers, 10 cm (3.9 inches) apart, that give scale to our images. The species grows to about 43 cm (17 inches) total length. It is marketed fresh and eaten when caught by hook and line fisheries for other bottomfish, but it is too uncommon to be targeted by commercial fisheries. The species is known from southern Japan through Taiwan, and the Philippines eastward to Guam, American Samoa, and Tahiti in the Society Islands. Like other groupers, it is a predator that feeds on small fish and crustaceans.

This colorful Cephalopholis grouper (also called a garish hind, goldbar grouper, garish rockcod, or Japanese cod - although it is not related to cods) was seen towards the end of Dive 01 of Mountains in the Deep at the Aunuʻu Unit of National Marine Sanctuary of American Samoa. The red dots are lasers, 10 centimeters (3.9 inches) apart, that give scale to our images. The species grows to about 43 centimeters (17 inches) total length. It is marketed fresh and eaten when caught by hook and line when fishing for other bottomfish, but it is too uncommon to be targeted by commercial fisheries. The species is known from southern Japan through Taiwan and the Philippines eastward to Guam, American Samoa, and Tahiti in the Society Islands. Like other groupers, it is a predator that feeds on small fish and crustaceans. Click image for credit and larger view.

video Watch video of an octopus seen during the dive.

 


NOAA Ship Okeanos Explorer
April 27, 2017

Dive 01: Aunuʻu Unit of National Marine Sanctuary American Samoa

After a successful week of outreach activities in Pago Pago, American Samoa, NOAA Ship Okeanos Explorer departed at 08:30 this morning to begin the Mountains of the Deep: Exploring the Central Pacific Basin expedition. Our first dive site was in the Aunuʻu Unit of National Marine Sanctuary of American Samoa, a small volcanic island approximately 10 nautical miles southeast of Pago Pago. The sanctuary area encompasses 15 square kilometers (5.8 square miles) and borders the island on three sides. The goal of this dive was to gather deepwater data about the habitat and biological communities to better understand their diversity and distribution, with a specific interest in bottom fishes, such as snapper and grouper. This dive had been identified as a priority by NOAA's Office of National Marine Sanctuaries. This was the first-ever deepwater exploration of the Aunuʻu Unit and we were not disappointed. The dive began at approximately 14:45 SST at a depth of 360 meters and continued upslope in search of bottomfish habitat. Much of the dive climbed a steep cliff that marked the edge of a coral platform that has grown on top of the volcanic rocks that formed the Samoan Islands. Finer sediments derived from the coral platform were transported down the steep slope within small grooved channels along its face. Though the dive was short, we accomplished our goal of locating bottomfish as well as several different species of corals – including cup corals, black corals, and sea fans. Other biology highlights included zoanthids, sea stars, a small aggregation of shrimp, an unusual crab – potentially an arrow crab, a squat lobster, duckbill fish, and an octopus. Much of the dive was spent climbing the steep wall which did not appear to have many crevices or caves. This lack of hiding areas likely explains the relatively few number of fish we saw. The remotely operated vehicles were secured on deck at 16:45 SST. We then began mapping operations. We will spend the next two days collecting sonar data as we transit to our next operating area, the high seas north of the Manihiki Plateau.


 


 

 

 

 

 

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