2016 Hohonu Moana: Exploring Deep Waters off Hawaiʻi






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The at sea team pose for a picture on the bow of the ship.

The at-sea team poses for a picture on the bow of the ship. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
March 18, 2016

Arrival to Kwajalein Atoll

This morning, the Okeanos Explorer arrived in Kwajalein Atoll. After more than three weeks at sea, and some of the worst weather the ship has seen in a long time, everyone was happy to see land. However, it will be a quick turnaround for much of the ship’s crew, with the next cruise departing in just five days. For those of us flying home, we have a couple of days in Kwajalein before the next flight leaves for the U.S. While the weather did not cooperate for much of the cruise, it was still a very successful cruise with eight great remotely operated vehicle dives, including the deepest ever conducted in the area, and the first-ever exploration of three unnamed seamounts. The data we have brought back will keep researchers busy for years.


 


 

 

 

Expedition Science Leads Daniel Wagner (foreground) and Jonathan Tree (background) use the transit days to take a final look at the samples we collected before they are packaged up to be sent to their repositories.

Expedition Science Leads Daniel Wagner (foreground) and Jonathan Tree (background) use the transit days to take a final look at the samples we collected before the samples are packaged up to be sent to their repositories. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
March 12 - 17, 2016

Transit Mapping

The Okeanos Explorer has spent the last five days transiting and mapping our way to Kwajalein Atoll in the Marshall Islands. While the transit days have given the engineers time to do some maintenance on the remotely operated vehicles (ROVs) and get ahead on their cruise wrap-up items, it puts a much heavier load on the mapping team. They normally only have to cover mapping operations 12-13 hours a day, but while we are transiting, they are now working 24 hours a day. To help fill the extra hours, several additional people, such as the expedition coordinator and a couple of the ROV pilots, got pulled into the operations. The extra efforts put towards mapping were well worth it. During our transit, we crossed over the Mid Pacific Seamounts, which have virtually no multibeam coverage, so we collected some of the first high-resolution data in this area. This data will hopefully be used to spark future research trips to this unexplored area.


 


 

 

 

D2 collects a rock on an unnamed seamount 180 nm south of Midway Island.

D2 collects a rock on an unnamed seamount 180 nautical miles south of Midway Island. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
March 11, 2016

Dive 8: Unnamed Seamount

Dive 8 was on a ridge located on the top portion of an unnamed seamount. The seamount is located ~200 miles south of Midway and was chosen as the last dive site of this expedition due to its geographic position and transit considerations to Kwajalein Atoll. The seamount was only mapped during this expedition and had therefore never been previously surveyed. The remotely operated vehicle (ROV) landed on the ridge crest at a depth of 3,994 meters. The substrate consisted of rounded cobble to boulder talus with little to no sediment and cemented by Mn crust. The bottom substrate was inhabited by a moderate density of sponges and corals. A moderate current was observed from the east towards the west. As the ROV moved up along the ridge crest, the density of corals remained moderate. Further up the slope, the ROV collected a coral specimen of Chrysogorgia that no one could identify. This species was relatively common throughout the dive. Along this portion of the dive track were channels incised in to the seafloor with light sediment concentrations and smaller cobble-pebble aggregations suggestive of downslope transport via these structures. As the ROV continued to move up the slope, the density of benthic animals remained moderately high. At 3,915 meters, the ROV collected a sample of a bamboo coral. Towards the end of the dive, the ROV moved towards and over the steep southern flank of the ridge crest that was constructed of pillow lava structures with no obvious layering. Here, the substrate was covered by a high density of barnacles, but sponges and corals were less abundant than on the ridge crest. The ROV left the bottom at a depth of 3,924 meters. Sadly, this was the last dive of the cruise, so once the ROV was on deck, we commenced transiting to the Marshall Islands.


 


 

 

 

D2 discovered one of the largest aggregations of brisingid sea stars anyone on the ship had ever seen.

D2 discovered one of the largest aggregations of brisingid sea stars anyone on the ship had ever seen. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
March 10, 2016

Dive 7: Castellano Seamount

Dive 7 was located on a ridge extending to the southeast of Castellano Seamount. This seamount had never been previously surveyed and therefore its geology and biological communities were completely unknown. The remotely operated vehicle (ROV) landed on the ridge crest at 2,013 meters. The substrate consisted of large Mn-encrusted volcanics, pebble to boulder in size, that were overgrown with a very high density of corals and sponges. There was little sedimentation at the landing site and the current was moderate from the east towards the west. As the ROV moved up along the ridge crest, the density of corals remained very high and consisted of numerous different species. Further up the slope, the ROV maneuvered around a large pinnacle, around which current flow was particularly strong. Along the entire dive track, layering of lava flows surrounded by volcanic rubble and talus were observed. The ROV left the bottom at a depth of 1,838 meters. Once the ROV was on deck, we commend transit mapping to our next dive site.


 


 

 

 

D2 investigates a coral on an unnamed seamount west of Salmon Bank

D2 investigates a coral on an unnamed seamount west of Salmon Bank. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
March 9, 2016

Dive 6: Unnamed Seamount West of Salmon Bank

Dive 6 was conducted on the top portion of an unnamed seamount west of Salmon Bank. The seamount was mapped for the first time during this expedition and had never been previously surveyed. Therefore, its geological age and fauna were completely unknown. The target start point of the dive was on the crest of a ridge that extends to the south of the seamount at a depth of 1,261 meters. The remotely operated vehicle (ROV) landed on a steep slope next to the ridge at 1,290 meters. The bottom consisted of Mn-encrusted surface with scattered cobbles and rock ledges. Few animals were observed close to the landing site and included an eel, a halosaurdid, sponges, and corals. At 1,291 meters, the ROV collected a geological sample, which was angular, dense, and lightly crusted with manganese. As the ROV began its traverse up the ridgeline, the source outcrop for this loose sample was observed as a highly angular Mn-encrusted volcanic ledge. The density of animals increased significantly along the ridge and consisted mainly of primnoid corals, with some chrysogorgid corals in between. The density of animals was consistently moderate, with some portions of high density. The ROV left the bottom at 649 meters. Over the course of the dive, the ROV covered a large depth range (~650 meters) and transversed the oxygen minimum layer. The density of animals did not decrease in this layer, but rather changed from one dominated by primnoid corals to one dominated by chrysogorgid corals and tall Saccocalyx sponges. After the ROV was on deck, we starting mapping as we transited to Castellano Seamount in preparation for Thursday’s dive.


 


 

 

 

A view of the solar eclipse.

A view of the solar eclipse. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
March 8, 2016

Solar Eclipse

We were prepared to dive on Salmon Bank this morning, but alas, the weather was still too rough to deploy the remotely operated vehicle. So, we worked on mapping two unnamed seamounts west of the bank. In the afternoon, we were treated to an exceptional phenomenon. The ship just happened to be in the perfect position to see a full solar eclipse. It was an amazing sight and an experience we will not soon forget. When the sun was in full eclipse, you could actually see what looked like a solar flare peeking out around  the moon.


 


 

 

 

The Okeanos Explorer beats its way into heavy seas.

The Okeanos Explorer beats its way into heavy seas. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
March 6-7, 2016

Terrible Weather

We have not been able to dive for three days now because of terrible weather. At the worst point, the seas were running 30 feet and the wind was blowing 40 knots. These conditions were substantially worse than the forecast called for. Given our remote location, there was no shelter nearby ,so all we could do was batten down the hatches and wait it out. As the sea and winds start to lie down, we are optimistic that we will be able to dive again on Wednesday.


 


 

 

 

A purple crinoid hangs out on a dead coral stalk.

A purple crinoid hangs out on a dead coral stalk. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
March 5, 2016

Dive 5: Unnamed Seamount East of Bank 9

Dive 5 was located on a ridge extending to the southwest of an unnamed seamount located east of Bank 9. The unnamed seamount had never been previously surveyed, and therefore its geological age is unknown. The objectives of this dive were to (1) collect rock samples that could be used to determine the geological age of the seamount and (2) survey for high-density communities of corals and sponges along the ridge and summit of the seamount. The plan was for the remotely operated vehicle (ROV) to move up the ridge until reaching the highest point of the seamount at ~1,600 meters. Then the ROV would survey towards the northwest along a flat plateau located at the top of the seamount until running out of bottom time. The ROV landed on the ridge crest at a depth of 1,754 meters. The substrate consisted of heavy botryoidal Mn-crusted volcanic rubble with channelized sediment and ripples. The density of animals was moderate and consisted mainly of sponges and black, bamboo, and gorgonian corals. At 1,759 meters, the ROV collected a small, Mn-crusted rock sample. The source lava flow of this geological sample is unknown. Further up the slope,at 1,703 meters, the ROV collected a Stichopathes wire coral, which was the most abundant coral throughout the dive. Throughout the ascent along the ridge, the substrate was composed of Mn-encrusted volcanic talus and rubble with interspersed, fully cemented Mn-crusted hardpan and larger rock features. Sedimentation was generally light, with some ripple structures present in the channelized sediments. Near the top of the ridge and before gaining the summit area, the substrate changed to a fragmented and laminated sheet flow that draped the ridgeline. Within separated portions of the sheet flow, loose volcanics were present. The second geological sample was taken from a separation between two sheet flow blocks. This sample appears to be a portion from the laminations present in the sheet flow. At the top of the seamount, several types of corals were present that had not been observed previously on the dive. Towards the end of the dive, the ROV collected a Bathypathes black coral, which had a commensal squat lobster on it; however, the commensal squat lobster swam out of the collection box before it could be secured. The density of animals was moderate to throughout the dive, with isolated patches of high density. After the ROV was recovered, we commenced mapping operations. The weather over the next couple days does not look good, so we are monitoring the forecasts very closely.


 


 

 

 

A swimming sea cucumber seen near the cliff.

A swimming sea cucumber seen near the cliff. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
March 4, 2016

Dive 4: North Side of Pioneer Bank

Dive 4 was located on a headwall scarp on the north side of Pioneer Bank, which included a steep pinnacle with a vertical relief of ~400 meters. The objective of the dive was to survey along the flanks and summit of the pinnacle for high-density communities of corals and sponges. The remotely operated vehicle (ROV) landed on the wall of the scarp at a depth of 1,513 meters. There was no current at the landing site and few animals were present. As the ROV moved up the wall, the density of benthic invertebrates remained low and included sponges, as well as chrysogorgid, primnoid, and bamboo corals. Several fish were observed along the wall including halosaurids, rattails, and a slickhead. At 1,503 meters, the ROV collected an unidentified glass sponge, which had a commensal crinoid on it. Further up the slope, the terrain became near vertical with large undercuts, causing the ROV to have to be pulled off the bottom to avoid entanglement of the umbilical cord. The ROV remained in midwater for approximately 30 minutes, during which time shrimp and crown jellyfish were observed. We then moved closer to the pinnacle and lowered back onto the bottom at 1,320 meteres depth. On the flanks of the pinnacle, the density of animals increased substantially and included patches of close to 100 percent benthic cover. These communities were dominated by the glass sponges and corals. The ROV left the bottom at a depth of 1,156 meters. Once the ROV was on deck we started a mapping transit to our next dive site.


 


 

 

 

GVA Nicky Applewhite stands the lookout watch as we map our way to our next dive site.

GVA Nicky Applewhite stands the lookout watch as we map our way to our next dive site. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
March 3, 2016

Weathered Out...Again

Unfortunately we were weathered out again today. We stayed around the dive site for a couple of hours in the morning to see if the seas were going to improve, but they did not. So, we started mapping our way back to the southeast to try and find better weather for Friday. 


 


 

 

 

A brittle star hangs out in a bubblegum coral.

A brittle star hangs out in a bubblegum coral. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
March 2, 2016

Dive 3: South of Pioneer Bank

Dive 3 was conducted on a rift zone ridge extending to the south of Pioneer Bank. Previous dives on the ridge have been conducted by both the Okeanos Explorer in 2015 (maximum depth of 2,119 meters) and the Hawaii Undersea Research Laboratory in 2003 (maximum depth of 1,813 and 1,825 meters). These dives documented one of the largest communities of deep-sea corals and sponges in the Monument. This high-density community extends for at least five miles at depths ranging between 1,800-2,100 meters along the top of the ridge. The objective of this dive was to survey the area below previous dives on the ridge in order to determine the lower depth limit of the high-density community. The target start point of the dive was approximately five miles south of the dive conducted on Pioneer Bank Ridge by the Okeanos Explorer in 2015.

The remotely operated vehicle (ROV) landed on the ridge crest at a depth of 2,352 meters. The bottom consisted of intact pillow lava flows and interspersed volcanic rubble with light sedimentation. The volcanic flows and rubble were covered with a moderate density of corals and sponges. As the ROV moved north along the ridge crest, the density of animals remained moderate and consisted mainly of primnoid and black corals, with scattered anemones and crinoids. The majority of corals and sponges were very small in size. A rock sample was collected at a depth of 2,353 meters which had hydoids growing it. Along the transit up the ridge, multiple local highs were interpreted as vent sources for proximal intact pillow lava flows. These elevated structures supported noticeable higher densities of organisms, and consisted mainly of small primnoid colonies. At 2,331 meters, the ROV collected coral specimens of both a Chrysogorgia sp. and a Pleurocorallium sp. colony that were right next to each other. As the ROV continued to move along the ridge crest, the densities of animals remained moderate to high. The ROV left the bottom at a depth of 2,343 meters.


 


 

 

 

Large swells continued to disrupt ship operations.

Large swells continued to disrupt ship operations. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
March 1, 2016

Another Weather Day

The ship was in large swells most of the day, running 15-20 feet with the occasional 22+ footer. During the late afternoon into evening, the seas started to lie down and we were able to get a small survey of Don Quixote Seamount on the way to the next dive site. We are optimistic about a dive on Wednesday.

 


 

 

 

Rough seas prevented the ship come conducting operations.

Rough seas prevented the ship from conducting operations. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
February 29, 2016

Rough Seas Mean No Dive

The seas were too large for operations today. We tried to collect some mapping data, but the data quality was poor, so we secured the sonars. The seas were running 15-18 feet and the winds were in excess of 25 knots most of the day. So the majority of the ship’s crew worked on projects inside the ship and we spent a lot of time looking at the weather forecasts. Tuesday does not look good, but there is a chance at a dive on Wednesday.

 


 

 

 

A dandelion siphonophore imaged in a submarine canyon north of French Frigate Shoals.

A dandelion siphonophore imaged in a submarine canyon north of French Frigate Shoals. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
February 28, 2016

Dive 2: North Side of French Frigate Shoals

Dive 2 of the cruise was conducted on the north side of French Frigate Shoals, in a submarine canyon. Just after the remotely operated vehicles (ROVs) went in the water, an oceanic white tip shark was seen checking out the ROV. Once the ROV reached the bottom, it found a flat area at a depth of 1,405 meters. The surface was characterized by a heavy sedimentary blanket with scattered Mn-encrusted volcanic boulders and rubble. At a depth of ~1,390 meters, the first intact lava flows were observed. These flows were laminar sheet flows with jumbled/platy or massive textures. As the ROV moved west towards the base of the canyon wall, a few more fishes were observed, including Snaptobranchid eels and Halosaurids. The density of benthic animals remained very low and included anemones, sponges, corals, sea cucumbers, and urchins. The slope changed to a vertical wall consisting of massive boulders that were covered with isolated aggregations of pink, gorgonian, and bamboo corals. As the ROV moved up the canyon wall, the benthic fauna remained low with isolated patches of corals. At the top of the wall, the slope became more gradual and the substrate consisted of volcanic rubble with heavy interspersed sediment. After the ROV reached the top of the canyon, it surveyed along the top of the wall, where scattered aggregations of corals were seen. The ROV then came up on a large pinnacle that was covered with high densities of corals and sponges. We had to end the dive a bit early because the weather was starting to build. Overnight it got so rough we could not even collect mapping data. While we are excited to get back in the water, looking at the forecast it might be a couple days before we can dive again.

 


 

 

 

Deep Discoverer collects a geological sample at 4300 meters East of Necker Island.

Deep Discoverer collects a geological sample at 4,300 meters east of Necker Island. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
February 27, 2016

Dive 1: Northeast Side of Necker Island

We completed our first remotely operated vehicle (ROV) dive of the cruise on the northeast side of Necker Island (Mokumanamana).

The ROV landed on a flat, heavily sedimented surface at 4,291 meters with weak or nor current. As the ROV moved northwestward towards the slope of the ridge, a few animals were observed including shrimps, sponges, sea anemones, sea cucumbers, and two fish. At ~4,280 meters, the heavily sedimented surface gave way to a more sloped surface with hardpan and isolated pillow lavas. Upon traversing up the slope near a depth of 4,250 meters, lobes of intact flows of pillow lavas were observed. A loose manganese-crusted volcanic rock was collected at 4,245 meters near the base of this flow. As the ROV moved up the slope, a couple of bamboo corals and anemones were observed. Sediment cover continued to decrease upslope to a surface composed of more manganese-encrusted pillow lavas with pockets of sediment. The manganese crusts appeared to be thin relative to the thicker crusts present on older (Cretaceous-age) flows. This observation suggests that these flows are younger in age and were emplaced during Hawaiian volcanic growth ~10 million years ago. A second manganese-crusted volcanic rock was collected at the base of another pillow lava flow very close to the end of the dive, at 4,222 meters.

Overnight, the ship commenced mapping operations. In the middle of the night, the ship received a distress call from a vessel and the U.S. Coast Guard requested we change our course to render aid. After about half an hour of heading towards the distressed vessel, the Coast Guard notified us that our assistance was no longer needed and we returned to our mapping plan.

 


 


 

 

 

In this screen capture of the EK60 data acquisition screen you can see the deep scattering layer near the surface.

In this screen capture of the EK60 data acquisition screen, you can see the deep scattering layer near the surface. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
February 26, 2016

Transit Mapping

The Okeanos Explorer transited over 350 miles in the last day and a half, on our way to our first dive site near Necker Island. Even though we did not deploy the remotely operated vehicles today, we were still exploring. The Okeanos is equipped with a suite of scientific sonars that not only map the seafloor but also the water column and the geological features just beneath the ocean bottom. As the sun set today, we used one of our water column sonars to watch one of the largest migrations on Earth. Every day, huge numbers of very small organisms come up from the depths at night to feed in shallower waters under the cover of darkness. This layer of organisms is often called the deep scattering layer because of the way it is seen in sonar. 


 


 

 

 

Chief Boatswain Jerrod Hozendorf loads some final stores before getting underway.

Chief Boatswain Jerrod Hozendorf loads some final stores before getting underway. Click image for credit and larger view.

 


NOAA Ship Okeanos Explorer
February 25, 2016

Underway!

After a two-day delay to address some lingering technical issues and to wait out some large swells passing the islands, the crew of the Okeanos Explorer was happy to get underway and start transiting to the Papahānaumokuākea Marine National Monument. The swells coming in from the northwest were over 18 feet when the ship came out from behind the lee of Barbers Point. While very big, the swells were a long enough period that the ride was not too bad overnight.


 


 

 

 

 

 

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