Okeanos Explorer (EX1708): Musicians Seamounts (ROV & Mapping)

Vessel: NOAA Ship Okeanos Explorer; Expedition Dates: September 6 - 30, 2017

Project Principals: Kasey Cantwell, NOAA/OAR/OER (Expedition Coordinator); Michael White, NOAA/OAR/OER (Mapping Lead)

Operations for this cruise will be conducted 24 hours/day and consist of daily remotely operated vehicle (ROV), overnight mapping, and full shore-based participation via telepresence. Operations will include the use of the ship's deep water mapping systems (Kongsberg EM302 multibeam sonar, EK60 split-beam fisheries sonars, Knudsen 3260 chirp sub-bottom profiler sonar, and Teledyne Acoustic Doppler Current Profilers), XBT and CTD casts in support of multibeam sonar mapping operations, OER's two-body ROV Deep Discoverer and Seirios, and the ship's high-bandwidth satellite connection for continuous real-time ship-to-shore communications. Operations are planned in and around Hawaii, the US EEZ, and in the High Seas around the Musicians Seamounts.

"Tropic of Cancer" Seamount

Area

"Tropic of Cancer" Seamount; Hawaiian Islands

Overview

Purpose

The main purpose of this dive was to validate predictive habitat suitability models for deep sea coral and sponge communities developed by NOAA's National Centers for Coastal Ocean Science. While no previous ROV or HOV dives have ever been conducted at this seamount, "Tropic of Cancer" seamount had high predicted habitat suitability for several deep coral genera, including: Antipatharia, Paragorgiidae, Isididae, Scleraxonia, Calcaxonia, Holaxonia, and Pennatulacea. This dive targeted high slopes and the summit ridge crest where suitability was predicted to be the highest. The first priority was to complete a photographic survey along the full transect. Secondarily, sample collections took place for unusual sightings or rare/novel species, along with rock samples to be used for age dating and geochemical study.

"Beach" Ridge

Area

"Beach" Ridge; Musicians Seamounts

Overview

Purpose

Deep-sea environments around the Musician Seamounts are unexplored. This dive was the first in a series whose purpose is to investigate the similarities and differences in community composition between seamounts and ridges in different parts of the Musicians Seamounts. Sharp elongate ridge features have been shown to harbor largescale, high-density coral communities on the NW Hawaiian Ridge. Therefore, there was a high potential that the elongate ridge-like feature of "Beach" Ridge was host to similar communities. The primary objective for this dive was to characterize the distribution and abundance of benthic fauna and acquire baseline information on deep sea habitats, seafloor geology, and biological communities with particular interest in deep-sea coral and sponge communities. A comparison of the diversity and distribution of coral and sponge communities across the seamounts to the north and to the Hawaiian Ridge and the broader North Pacific is important to understanding the biogeography and connectivity of communities in the Pacific. In addition, the biological and geological sampling at depth will enable a comparison with other areas of the Pacific sampled as part of NOAA's CAPSTONE program.

Beethoven Ridge

Area

Beethoven Ridge; Musicians Seamounts

Overview

Purpose

The primary objective for this dive was to characterize the distribution and abundance of benthic fauna. A comparison of the diversity and distribution of coral and sponge communities across the seamounts to the north, the Hawaiian Ridge, and the broader North Pacific is of particular importance to understanding biogeography and connectivity of communities in the Pacific. Sharp elongate ridge features have been shown to harbor large-scale, high-density coral communities on the NW Hawaiian Ridge. As such, the elongate ridges in these areas have a high potential to host similar communities. The priorities were to complete a videographic survey along the transect and collect unique or representative biological and geological samples while covering as much of the feature as possible.

Sibelius Seamount

Area

Sibelius Seamount; Musicians Seamounts

Overview

Purpose

The primary objective for this dive was to characterize the distribution and abundance of benthic fauna along a scarp on the eastern side and upper flank of a large indentation, or cut-out, in the seamount, proposed to be the headwall section of a landslide. A comparison of the diversity and distribution of coral and sponge communities across the seamounts to the north and to the Hawaiian Ridge and the broader North Pacific is of particular importance to understanding biogeography and connectivity of communities in the Pacific. The first priority was to complete a photographic survey along the transect, covering as much of the feature as possible. Secondarily, sample collections occurred for unusual sightings, or rare/novel species. A representative rock sample was also taken for further petrologic, geochemical, and/or dating analyses.

Gounod Seamount

Area

Gounod Seamount; Musicians Seamounts

Overview

Purpose

The primary objective for this dive was to characterize the distribution and abundance of benthic fauna at Gounod Seamount. A comparison of the diversity and distribution of coral and sponge communities across the seamounts to the north and to the Hawaiian Ridge and the broader North Pacific is of particular importance to understanding biogeography and connectivity of communities in the Pacific. The first priority was to complete a photographic survey along the transect, covering as much of the feature as possible. Secondarily, sample collections occurred for unusual sightings, or rare/novel species. A representative rock sample was also taken for further petrologic, geochemical, and/or dating analyses. The dive plan was to survey one of a series of small cratered features close to the summit of Gounod Seamount. These volcanic constructs were identified in the multibeam data as a sequence of terraced pancake cones, a landform seen elsewhere in the main and Northwestern Hawaiian Islands. While not especially rare, it is a curious feature because of its eruption style and geomorphological representation. The primary objective for this dive was to characterize the distribution and abundance of benthic fauna and to collect rock samples that can be used to determine the age of the feature and geochemistry of its host rock. A comparison of the diversity and distribution of coral and sponge communities across the seamounts to the north and to the Hawaiian Ridge and the broader North Pacific is of particular importance to understanding the biogeography and connectivity of communities in the Pacific. The dive satisfies the CAPSTONE science themes to "Identify and map vulnerable marine habitats - particularly high-density deep-sea coral and sponge communities," and to "investigate the geologic history of Pacific seamounts".

Debussy Seamount- Aborted Dive

Area

Debussy Seamount- Aborted Dive; Musicians Seamounts

Overview

Purpose

Dive aborted early. See EX1708 Dive 7 for dive on Debussy Seamount.

Debussy Seamount

Area

Debussy Seamount; Musicians Seamounts

Overview

Purpose

This is the first of two dives that will investigate the similarities and differences in community composition between two relatively isolated seamounts (Mussorgsky and Debussy) that occupy the gap between the two main groups of the Musicians Seamounts. The primary objective for this dive was to characterize the distribution and abundance of benthic fauna, in particular corals, to examine the diversity, biogeography, and connectivity of coral living at Debussy Seamount compared to the isolated Mussorgsky Seamount and to the rest of the sites visited during this expedition. A comparison of the diversity and distribution of coral and sponge communities across the seamounts to the north and to the Hawaiian Ridge and the broader North Pacific will help describe the biogeography and connectivity of communities in the Pacific. The dive satisfies the CAPSTONE science theme to "Identify and map vulnerable marine habitats - particularly high-density deep-sea coral and sponge communities."

Wagner Seamount

Area

Wagner Seamount; Musicians Seamounts

Overview

Purpose

One of the main objectives of this dive was to collect representative rock samples of the feature for geochemical analysis and isotopic dating so as to examine the interaction of hot spot and mid-ocean ridge interactions. The other objective for this dive is to characterize the distribution and abundance of benthic fauna, in particular corals, to examine the diversity, biogeography, and connectivity of corals living the northern seamount group compared to those observed in the southern seamount group and to the rest of the sites visited during this expedition. A comparison of the diversity and distribution of coral and sponge communities across the seamounts to the north and to the Hawaiian Ridge and the broader North Pacific will help describe the biogeography and connectivity of communities in the Pacific. The dive satisfies the CAPSTONE science themes to "investigate the geologic history of Pacific seamounts" and to "identify and map vulnerable marine habitats - particularly high-density deep-sea coral and sponge communities."

Verdi Seamount

Area

Verdi Seamount; Musicians Seamounts

Overview

Purpose

This dive had two main purposes. One was to explore a deep volcanic elongate ridge feature and collect rock samples to provide clues as to the origin of the lineament and the surrounding seamounts, informing a better understanding of the geologic history of the region. Thus, it satisfies the CAPSTONE theme to "investigate the geologic history of Pacific seamounts." The second purpose of the dive was to inform biogeographic patterns of benthic fauna throughout the Musicians Seamounts. A comparison of the diversity and distribution of biological communities (namely,corals and sponges) across the seamounts and to the Hawaiian Ridge and the broader North Pacific will help describe the biogeography and connectivity of communities in the Pacific. This dive satisfies the CAPSTONE science theme to "Identify and map vulnerable marine habitats - particularly high-density deep-sea coral and sponge communities."

Shostakovich Seamount

Area

Shostakovich Seamount; Musicians Seamounts

Overview

Purpose

One purpose of Dive 10 was to explore the summit of a volcanic elongate ridge known as Shostakovich Seamount, providing clues as to the origin of the lineament and surrounding seamounts. Thus, it satisfies the CAPSTONE theme to "investigate the geologic history of Pacific seamounts." Secondly, this dive endeavored to contribute to the knowledge of biogeographic patterns of benthic fauna throughout the Musicians Seamounts. A comparison of the diversity and distribution of biological communities (namely, corals and sponges) across the seamounts and to the Hawaiian Ridge and the broader North Pacific will help describe the biogeography and connectivity of communities in the Pacific. This dive satisfies the CAPSTONE science theme to "Identify and map vulnerable marine habitats - particularly high-density deep-sea coral and sponge communities." The third objective of this dive was to explore and characterize the water column, the largest and least known biome on the planet.

Water Column 1

Area

Water Column 1; Musicians Seamounts

Overview

Purpose

The water column is one of the most underexplored environments on the planet. Basic information is lacking on the distributions and abundances of midwater organisms in most parts of the globe, and the vicinity of the Musicians Seamounts remains poorly explored. ROV visual surveys provide crucial data on the distributions, abundances, and behaviors of a variety of midwater animals. ROV surveys are especially well-suited to observe the understudied gelatinous fauna, which commonly fall apart using traditional net sampling methods. Collecting acoustic backscatter data (Simrad EK60) throughout the cruise - including during ROV transects - will complement the ROV surveys by providing critical information on the depth and extent of deep scattering layers, diel vertical migrations, and ROV avoidance behavior.

Mussorgsky Seamount

Area

Mussorgsky Seamount; Musicians Seamounts

Overview

Purpose

The purpose of this dive was to carry out the second of two dives to investigate the similarities and differences in community composition between two isolated seamounts (Mussorgsky and Debussy) that occupy the gap between the two main groups of the Musicians Seamounts. The primary objective for this dive was to characterize the distribution and abundance of benthic fauna, in particular corals, to examine the diversity, biogeography, and connectivity of corals living here compared to the lesser isolation of Debussy Seamount. Data from this dive will be used to compare benthic fauna distribution to Debussy Seamount and to the rest of the sites visited during this expedition. A comparison of the diversity and distribution of coral and sponge communities across the seamounts to the north and to the Hawaiian Ridge and the broader North Pacific will help describe the biogeography and connectivity of communities in the Pacific. The dive satisfies the CAPSTONE science theme to "Identify and map vulnerable marine habitats - particularly high-density deep-sea coral and sponge communities."

Paganini Seamount

Area

Paganini Seamount; Musicians Seamounts

Overview

Purpose

The primary objective for this dive was to characterize the distribution and abundance of benthic fauna. A comparison of the diversity and distribution of coral and sponge communities across the seamounts to the north and to the Hawaiian Ridge and the broader North Pacific is of particular importance to understanding biogeography and connectivity of communities in the Pacific. The dive satisfies the CAPSTONE science theme to "Identify and map vulnerable marine habitats - particularly high-density deep-sea coral and sponge communities."

Liszt Seamount

Area

Liszt Seamount; Musicians Seamounts

Overview

Purpose

This dive was the first of two dives to investigate the interaction between hot spot volcanism and fracture zones. Lizst Seamount is directly over the closely-spaced fracture zones. Specifically, this dive investigated the geomorphology and targeted rock collections to look for evidence of different magma types or rock composition at areas close to the Murray Fracture Zone. Another goal was to seek evidence of postemplacement deformation of the volcanic edifice due to continuing motion across the fracture zone. This dive also surveyed the biologic communities present on the seafloor to characterize their distribution and abundance.

Mozart Seamount

Area

Mozart Seamount; Musicians Seamounts

Overview

Purpose

This dive was the second of two dives to investigate the interaction between hotspot volcanism and fracture zones. Mozart Seamount is near the Murray Fracture zone, but not directly intersecting it. Specifically, the purpose of this dive was to investigate the geomorphology and to target rock collections to look for evidence of different magma types or rock composition at areas close to the Murray Fracture Zone, along with any differences between Mozart Seamount and observations made at Liszt Seamount (Dive 14). Another goal was to seek evidence of post-emplacement deformation of the volcanic edifice due to continuing motion across the fracture zone. This dive also surveyed the biologic communities present on the seafloor to characterize their distribution and abundance.

Water Column 2

Area

Water Column 2; Musicians Seamounts

Overview

Purpose

The water column is one of the most underexplored environments on the planet. Basic information is lacking on the distributions and abundances of midwater organisms in most parts of the globe, and the vicinity of the Musicians Seamounts remains poorly explored. ROV visual surveys provide crucial data on the distributions, abundances, and behaviors of a variety of midwater animals. ROV surveys are especially well-suited to observe the understudied gelatinous fauna, which commonly fall apart using traditional net sampling methods. Collecting acoustic backscatter data (Simrad EK60) throughout the cruise - including during ROV transects - will complement the ROV surveys by providing critical information on the depth and extent of deep scattering layers, diel vertical migrations, and ROV avoidance behavior.

Rapano Ridge

Area

Rapano Ridge; Musicians Seamounts

Overview

Purpose

The primary objective for this dive is to characterize the distribution and abundance of benthic fauna. The dive is part of a series that will investigate the similarities and differences in community composition between seamounts and ridges in different parts of the Musicians Seamounts. A comparison of the diversity and distribution of coral and sponge communities across the seamounts to the north and to the Hawaiian Ridge and the broader North Pacific is of particular importance to understanding biogeography and connectivity of communities in the Pacific.

Schumann Seamount

Area

Schumann Seamount; Musicians Seamounts

Overview

Purpose

The primary objective for this dive was to characterize the distribution and abundance of benthic fauna. A comparison of the diversity and distribution of coral and sponge communities across the seamounts to the north and to the Hawaiian Ridge and the broader North Pacific is of particular importance to understanding biogeography and connectivity of communities in the Pacific. Sharp elongate ridge features have been shown to harbor large-scale, high-density coral communities on the NW Hawaiian Ridge. As such, the elongate ridges in these areas have a high potential to host similar communities. The dive satisfies the CAPSTONE science theme to "Identify and map vulnerable marine habitats - particularly high-density deep-sea coral and sponge communities."

Mendelsohn Seamount

Area

Mendelsohn Seamount; US EEZ around Hawaii, South of Musicians / North of Hawaiian Islands

Overview

Purpose

Mendelsohn Seamount is a bit of an enigma. Is it part of the Musicians Seamounts or a separate second parallel chain of seamounts to the Hawaiian chain? The offset bunch of seamounts located between the Hawaiian Ridge and the Liliokalani Ridge are enigmatic. The fork at the end of the Liliokalani seamount chain is also enigmatic (i.e., How does a hot spot create a fork?). One potential explanation is they are an endpoint for a hot spot plume that originated in the Liliokalani hot spot trace but much later, thus explaining the forked nature of the latter. Additional rock samples could be very useful in determining if this hypothesis is correct. This could also help inform general plate tectonic questions that linger with the Hawaiian hot spot chain regarding where the plate actually changed direction, or rather, did the Hawaiian plume drifted to form the bend? In other words, if a second trace recorded a similar bend, then the plate must have changed direction. Biologically, this seamount also sits at a pivotal point. It could serve as a biological stepping stone for benthic communities. Data from this dive will help establish the connection between the NWHI and the Musicians Seamounts. A comparison of the diversity and distribution of coral and sponge communities across the Musicians Seamounts to the north and to the Hawaiian Ridge and the broader North Pacific is of particular importance to understanding the biogeography and connectivity of communities in the Pacific.

Middle Bank

Area

Middle Bank; Just outside of PMNM, US EEZ Hawaii

Overview

Purpose

This dive, located just outside the boundary of PMNM, was carried out at the request of the Monument staff and NOAA NOS NCCOS. The objectives were 1) to explore fish and invertebrate boundary communities and 2) ground truth coral habitat suitability and taxonomic richness models based on multibeam sonar bathymetry and slope data. Management unit species within the precious coral and bottomfish fisheries were of particular interest. The selection of this dive site on Middle Bank was based on high-resolution multibeam bathymetry, slope, and backscatter data revealing the presence of a pinnacle feature that likely had populations of bottomfish and precious corals. In addition, regional coral habitat suitability models indicated it was close to an area that had high potential habitat suitability for the occurrence of seven or more genera of coral species. Draft models were produced as a collaborative effort by NOAA NOS NCCOS as part of a BOEM-funded Biogeographic Assessment of the Main Hawaiian Islands. More information about the project can be found at: http://coastalscience.noaa.gov/projects/detail?key=163.

Caiman Targets

Area

Caiman Targets; Oahu

Overview

Purpose

To investigate a series of sonar anomalies in an effort to locate the remains of the Japanese fast submarine I-203 (Sentaka-type) captured at the end of WWII, brought to Pearl Harbor as part of the 5-submarine prize fleet, and disposed near this area in 1946. If found, conduct non-invasive survey focusing on the innovative features of this rare fast attack vessel.

USS Baltimore

Area

USS Baltimore; Oahu

Overview

Purpose

Maritime heritage dive to conduct non-invasive video survey of remains of USS Baltimore, late 19th-century USN protected cruiser scuttled near Oahu in 1944, including: documentation of specific 19th-century features; photogrammetry and mosaic data compilation; assessment of scuttling damage; assessment of preservation/deterioration status; marine species inventory.