Beyond the Blue: Palau Mapping

Building Local Capacity in Deep-Sea Science

This summer, NOAA Ocean Exploration and the Palau International Coral Reef Center (PICRC) partnered to explore the deep waters of the Palau National Marine Sanctuary (PNMS). In addition to expanding mapping coverage within the sanctuary, the collaboration also focused on leveraging local expertise to advance deep-sea research, and supporting PICRC in building regional capacity to carry this work forward.

As part of this effort, five junior regional advisors (JRAs) joined a nine-week workforce development program that combined onshore training in Palau with offshore experience at sea. While onshore, these Palauan students and early-career scientists shadowed PICRC staff in various disciplines, including environmental DNA (eDNA) sample processing, aquarium operations, outreach, and education. They also joined virtual webinars with NOAA Ocean Exploration staff to learn more about NOAA’s exploration initiatives, connecting their local work to broader exploration efforts.

At sea, the JRAs served as guest scientists aboard NOAA Ship Okeanos Explorer, where they learned ship operations and supported eDNA sampling and seafloor mapping efforts. Together, these experiences provided a strong foundation in both technical skills and communication, while directly contributing to the exploration and characterization of the PNMS.

Independent Projects Explore Deep-Sea Biodiversity in PNMS

Established in 2015, the PNMS is one of the world’s largest marine protected areas, composed primarily of deep-sea ecosystems. Improving knowledge and characterization of these vast, largely unexplored habitats is essential for effective management. As Palau’s leader in marine science, PICRC plays a key role in this work and is responsible for coordinating research, management, and outreach for the sanctuary. As such, a central component of the JRA program was the development of independent research projects based on expedition data collected within PNMS.

With guidance from NOAA and PICRC scientists, the JRAs designed and carried out projects to study biodiversity in the sanctuary, drawing on an extensive dataset of deep-sea remotely operated vehicle (ROV) video observations collected by Ocean Exploration Trust (OET) in 2024. The JRA projects spanned a range of topics, including:

• Species-habitat relationships: Examining the distribution and benthic associations of deep-sea crinoids, also known as “sea lilies” or “feather stars.” Crinoids are a type of echinoderm with feathery appendages used for suspension feeding.
• Environmental influences on biodiversity: Investigating how abiotic factors like oxygen, temperature, and salinity shape species abundance and community structure.
• Community comparisons across geological features: Analyzing distinct biological assemblages hosted on newly discovered seamounts, including differences between northern and southern seamounts, and comparing seamount sites along a deep-sea trench.

The JRAs’ preliminary findings reveal high species diversity in the deep waters of the PNMS, and highlight how environmental factors may influence species distribution. The projects documented a high abundance of crinoids — particularly Comatulida sp., the most prevalent group observed across sites — and found that these species occupy a wide range of depths, suggesting habitat partitioning and a mix of generalist and specialist strategies. Examination of species compositions showed distinct patterns by depth, with poriferans and cnidarians more common at shallower sites, while echinoderms, arthropods, chordates, and annelids were more abundant at deeper depths, possibly influenced by temperature or oxygen gradients. There were also notable differences in biodiversity across seamount locations, potentially driven by variations in geological composition, substrate availability, or deep-sea currents affecting nutrient and temperature conditions.

While these results offer an important glimpse into the drivers of deep-sea biodiversity in Palauan waters, this initial characterization is only the first step toward understanding these deep-sea environments and the life they support. The JRAs also noted limitations in the dataset, including incomplete species identifications. Non-invasive tools like ROVs offer invaluable insights into remote, deep-sea habitats, but many organisms observed remain undescribed or could not be classified to the species level using ROV data alone, instead requiring detailed examinations of physical specimens for accurate identification. This emphasizes the importance of continued exploration and research, as well as complementary methods, such as eDNA analysis, to advance deep-sea science.

Through these projects, the JRAs not only gained hands-on experience in data analysis and science communication but also contributed new knowledge about deep-sea ecosystems in Palau. Their work provides a foundation for future research, supports effective management of the PNMS, and helps build the next generation of Palauan deep-sea scientists.

Powered by Collaboration

This capacity-building effort was made possible through ongoing collaboration between NOAA Ocean Exploration, PICRC, and OET. The JRAs’ projects drew on data from three NOAA-funded expeditions conducted by OET aboard E/V Nautilus in Palauan waters during the fall of 2024 — Lebuu’s Voyage I (NA167), Lebuu’s Voyage II (NA168), and Mapping and Water Column Exploration Offshore Palau (NA169). Across these expeditions, scientists spent 38 days at sea, mapped over 21,900 square kilometers (8,450 square miles) of seafloor, mapped and identified 16 previously unknown seamounts, completed 17 ROV dives using ROV Hercules, collected more than 200 biological and geological specimens, and gathered nearly 150 eDNA samples. Working in close partnership with PICRC, these missions also centered Palauan voices by hosting local scientists, educators, and students, incorporating Palauan culture and language into shipboard activities, and engaging schools and communities through culturally-grounded outreach.

Following the expeditions, a team of researchers from the Deep-Sea Animal Research Center at the University of Hawaiʻi at Mānoa manually annotated the ROV video data. They identified observations of deep-sea fauna seen across hundreds of hours of dive footage to the most precise taxonomic level possible, generating 40,963 observations of deep-sea fauna totalling 112,289 individuals. This growing dataset served as a powerful platform for the JRAs’ research projects, and will continue to support both current and future scientific investigations.

Building on this foundation, NOAA Ocean Exploration conducted three additional mapping-focused expeditions in Palauan waters aboard NOAA Ship Okeanos Explorer during the 2025 field season. These efforts added an additional 115,588 square kilometers (44,629 square miles) of seafloor mapping data and collected 649 additional eDNA samples to advance marine species monitoring in the PNMS. Palauan scientists remained central to this effort: a number of PICRC researchers, including the JRAs, and other local collaborators joined the expeditions, contributing to exploration efforts that will help to further characterize deep waters within the sanctuary.

Exploration is Only the First Step

Through this international collaboration — which brought together leading U.S. and Palauan scientists, cutting-edge technology, and the next generation of Palauan researchers — NOAA Ocean Exploration and partners are working together to expand knowledge to support the responsible management of the PNMS for years to come.

But exploration is only the first step. The exploratory mapping and ROV surveys conducted aboard vessels like E/V Nautilus and NOAA Ship Okeanos Explorer help to bring deep-sea ecosystems to light, generating baseline data that fuel further research, new hypotheses and discoveries, and lead to science-informed management decisions. Collaboration and training opportunities are key to these next steps. One JRA reflected that, “As a Palauan, conservation and understanding the ocean are part of my culture. Knowing my environment has high value, and helps me pass that knowledge on to the next generation.” These experiences not only help to strengthen local capacity, but also inspire and equip young scientists to carry this work forward into the future.