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Biodiversity and Beauty at Johnston Atoll

A look back at the OET expedition to the Central Pacific with our onboard scientist Raissa Hogan.

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In 2023, OET proudly announced a new partnership with Ocean Census – the largest programme in history dedicated to species discovery in the ocean.  Together, OET and Ocean Census are facilitating the discovery of new species from the deep sea – the largest habitat on Earth.

In August, Ocean Census Science Network participant Raissa Hogan joined the Ocean Exploration Trust NA153 expedition ‘Deep Sea Biodiversity & Ancient Seamount Exploration’, travelling within the Johnston Atoll Unit of the Pacific Remote Islands Marine National Monument (PRIMNM), starting and ending in Honolulu.

PRIMNM is now the second largest Marine Protected Area in the United States, although large areas remain completely unexplored. Further exploration is urgently needed to address deep-water habitat scientific knowledge gaps and contribute to a management plan which is currently under development for the region. The expedition was funded by NOAA Ocean Exploration.

Raissa became part of the science team onboard E/V Nautilus, spending 27 days exploring the Central Pacific and using ROVs to a Max Depth of 3,200m using ROV dives, alongside survey work using acoustic sonar, adding capacity to species discovery alongside the OET expedition targets. 30 scientists, engineers and students sailed on the expedition, supported by 73 professionals from 52 different institutions who joined remotely to increase taxonomic support, including Ocean Census Science Director Prof. Alex Rogers and Science Manager Denise Swanborn. Also onboard was a diverse crew including artists, educators, journalists, ROV videographers, interns and ROV pilots, gaining valuable at sea experience and helping to form a busy but supportive environment. As part of the OET’s commitment to education, people were able to watch dives in real time via their YouTube channel, bringing the excitement of ocean exploration to students and public audiences around the world.

You can help to raise awareness of the importance of marine life by sharing the film with friends and colleagues.

Raissa, a PhD candidate at The University of Galway, travelled from her forest home on the west coast of Ireland to Hawaii to join the expedition. Her area of research, focused on the evolution and biodiversity of deep-sea coral, with an emphasis on sea pens (Pennatuloidea) and black corals (Antipatharia), was a good fit for the expedition. The Hawaiian region is renowned for hosting a unique and diverse array of black corals, making it a paradise for research in this area. During the expedition, Raissa even earned the title ‘Sea Pen Queen’.

Onboard, Raissa’s time was divided between the ROV control van and the wet lab, processing samples, as well as making time for daily science meetings, meals and sleep onboard this busy 24/7 research vessel. A wide variety of biological samples are collected by Nautilus, and different techniques are needed depending on the size and fragility of the specimen. The process of taxonomy entails assimilating integrative data and often involves multiple stages before we can successfully describe a new species or understand its placement within existing classifications. Raissa was interviewed by Communications Fellows for the OET Blog on the important link between taxonomy and exploration.

“The collaboration between Ocean Census and OET has given me this amazing opportunity to be a part of the Johnston Atoll expedition, where I can observe and acquire samples I haven’t studied before. I have mostly been working with collections from the Northeast Atlantic, so this is my first time surveying the deep waters of the Pacific. The knowledge and networking I’m gaining from being part of this cruise is unique, and I am excited for future discoveries.

I view taxonomy, much like many sciences, as a field that demands love and curiosity. It necessitates an inquisitive mind, adept observational skills across varying scales, and a healthy dose of patience.

Taxonomy stands as a discipline of its own, yet it serves as the primary foundation for a multitude of other subjects. If we aspire to fathom various aspects of biodiversity, ecology, evolution, distribution, species boundaries, taxonomy becomes indispensable.”

Raissa Hogan, Ocean Census Science Network participant 

As a mixed-race woman, born and raised in Brazil, Haissa was also able to mark International Day of Indigenous Peoples on 9th August, helping to raise awareness of the marginalisation of indigenous communities and their unique experiences and perspectives, and the need to protect their rights. During the expedition she spoke about the significance of supporting regional taxonomic specialists and small teams who are performing important species discovery work, often without the resources of larger organisations in the northern hemisphere.

Despite logistical challenges as a result of Hurricane Dora, the expedition completed 11 successful ROV dives at depths ranging from 975-3,163 metres for a total dive time of over 170 hours. Noteworthy observations included coral gardens and evidence of extensive past lava flows at the summits of seamounts. Overall, hundreds of species were documented, including several potentially undescribed species. Preliminary observations indicate that 14 biological samples collected on this expedition represent either new species or new records for the region and there remains lots to be learned.

The team experienced stunning wildlife. Check out the image gallery below for up-close shots of animals including a translucent sea pig, Bolosoma sponges and sea dandelions.

Special thanks to OET, the crew of E/V Nautilus and everyone that supported the expedition from shore.

Catch up on Nautilus film and share in the joy of the OET Corps of Exploration with the highlight compilation of some of the best views from the seafloor on the seamounts surrounding Johnston Atoll.

Download the NA153 Expedition Summary.

If you’re a scientist interested in participating in future expeditions, register for the Ocean Census Science Network to support our growing community and be the first to hear about upcoming opportunities.

Thank you to Ocean Exploration Trust/ Nautilus Live for topside images and to Ocean Exploration Trust/ Nautilus Live, NOAA for underwater images.

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