The waters of the remote Pacific territories are among the least explored U.S. holdings in the Pacific Ocean. As Nautilus travels into the central Pacific Ocean for the first time, the first expedition in this region from June 23 to July 13, 2019 will target seamounts, hills, and ridges deep waters deeper than 150m around within the US Exclusive Economic Zone (EEZ) in the vicinity of Kingman Reef, Palmyra Atoll, and Jarvis Island. Collectively, these areas lie within one of the largest marine protected areas in the world, the Pacific Remote Islands Marine National Monument (PRIMNM). Established in 2009, and later expanded in 2014, PRIMNM encompasses 7 islands and atolls as well as numerous seamounts, guyots, and ridges hidden beneath the sea surface. Shallow-water environments in PRIMNM contain biodiverse communities of fishes and coral species, and terrestrial environments are important habitats for seabirds colonies. Following on the heels of a 3-year NOAA Campaign to Address Pacific monument Science Technology, and Ocean NEeds (CAPSTONE, 2015-2017), a major multi-year effort to collect baseline information on unknown or poorly explored deep waters around remote Pacific territories, this expedition will expand upon biological and geological efforts to characterize deep-water features. This Nautilus expedition is sponsored by NOAA Office of Exploration and Research, with participating organizations including U.S. Fish and Wildlife Service, Temple University, University of Rhode Island, Oregon State University, and University of Hawai’i.
Revealing Enigmatic Seamounts and Deep Sea Coral Colonies
Seamounts are likely to be the most abundant features to be explored on this expedition. These features can in turn be composed of smaller topographic features like steep slopes, ridges, or depressions. Seamounts can be broken down into different types like flat-topped guyots (also called tablemounts) or sharp peaked cones, each having potentially different geological history or types of biological communities. Numerous enigmatic, or little understood, seafloor features including depressions and seamount moats have been previously mapped along and adjacent to the Line Islands. The proposed origins for these features suggest markedly different benthic habitats, which may provide unique environments for potential new species, and basalt samples of the seamounts in the region may provide additional understanding of the complex volcanic and tectonic history of the Line Islands. Mineral-rich ferromanganese crusts have also been identified from seamounts in the north and equatorial Pacific making them potentially attractive resources for deep-sea mining. Characterizing protected seamount environments, like those in PRIMNM, will allow for a baseline assessment of crust communities to compare to those potentially impacted in similar areas of the remote central Pacific.
Deep sea corals and sponges are some of the most abundant large organisms observed on the deep seafloor, yet many questions remain about their distribution and diversity on seamounts, islands, and atolls in the central Pacific. Structures produced by deep-water coral colonies have been identified as important habitat for invertebrate and fish fauna. In past expeditions to these areas, some features have revealed high density and high diversity communities at depths up to 2500m. Compared to relatively well-studied areas like Hawaii, very little known about remote populations but questions the team hopes to shed light on during this expedition include: How abundant and diverse are species in these remote areas? And how do communities compare across depth? What might the presence of some cosmopolitan species reveal about the connectivity of populations and biogeography between features or provinces? Given the remoteness of these territories, and lack of previous exploration, it is expected that the chances of encountering new species is high.
Diving Deeper into Data Collection for Pacific Remote Islands
The Pacific Remote Islands Marine National Monument is among the largest marine protected areas in the world, but remains poorly explored due in part to its spatial isolation. While the diversity of species in shallow waters is relatively well known, deeper waters are not. In recent years there have been a few but growing list of expeditions to explore deep-sea environments the PRIMNM units of Kingman & Palmyra and Jarvis Island. In 2005, the Hawai’i Undersea Research Lab using the manned Pisces submersibles, explored bathyal depths of these three regions. More recently in 2017, the Mountains in the Deep expedition on NOAA Ship Okeanos Explorer conducted significant multibeam mapping operations and providing substantial resources for future dive planning. An expedition on Schmidt Ocean Institute’s R/V Falkor later that year explored shallower depths for evidence of ancient coastlines that were drowned during historical sea level rise around Kingman Reef and Palmyra Atoll. While these expeditions represent leaps and bounds in exploration of the deep sea, much remains to be explored to consider these areas well-characterized with respect to biological diversity and geological underpinnings.
The addition of high-resolution seafloor mapping data from Nautilus around these remote regions will add to these previous expeditions and aid in future explorations and species or habitat modelling. Characterization of vulnerable or sensitive habitats within the areas of Kingman & Palmyra and Jarvis units of PRIMNM will greatly support management and conservation efforts in the area. Sampling of targeted biology through voucher specimen collection will likely result in the identification of potential new species and enhanced knowledge about species ranges in this remote region. Several buoys and drifters will be deployed during this expedition in international waters in support of education outreach and scientific activities.
- Acquisition of high-resolution bathymetry in areas where no or patchy mapping data exists. Priority targets include seamounts, guyots, submarine banks, ridges, and margins around atolls and islands.
- Exploration and characterization of diversity of benthic habitats, including deep-water corals, sponges, and fish habitats, on seafloor features throughout the Kingman & Palmyra and Jarvis Units of PRIMNM and the U.S. Exclusive Economic Zone.
- Identification of high-density and high-diversity deep-water sponge and coral communities that would contribute to biogeographic knowledge of the area.
- Exploration of geological structure of seamounts, particularly those with “moat ring” formations.
- Obtaining basalt samples of seamounts for subsequent dating geochemical analyses.
- Identifying potential benthic communities present on mineral crust zone seamounts in the north and equatorial central Pacific.
- Obtaining data in support of conservation and exploration goals for remote units of the Pacific Remote Islands Marine National Monument.
- Additional seafloor mapping in the Cook Island Exclusive Economic Zone north of Manihiki Plateau.
Sampling items will primarily target the following:
- Deep-water corals, sponges, and associated organisms
- Other biological specimens for potentially new species, range extensions, connectivity
- Rock samples to identify mineral crusts and date geologic features
Niskin bottle water samples for environmental DNA and possible seawater carbonate analysis
Expedition Tools & Technologies
ROVs Hercules and Argus
EM302 multibeam sonar
Knudsen sub-bottom profiler
During transits in international waters, several instruments will be launched including:
- Scripps Wave Buoys
- Educational Passages Sailboat The Perry
- National Geographic Deep-Ocean Drop Camera