Revealing Roo Rise: OceanX Expedition Establishes a New Scientific Baseline for the High Seas
- Written by Media Outreach
Expedition maps more than 12,800 square kilometers of seabed and documents deep-sea biodiversity across a little-studied high seas region
SINGAPORE – Media OutReach Newswire – 4 August 2026 – OceanX today announced the completion of High Seas: Revealing Roo Rise, a 22-day scientific expedition aboard R/V OceanXplorer to investigate one of the eastern Indian Ocean's most ecologically significant and under-characterized high seas regions. 
Scientists monitor a deep-sea sampling dive from Mission Control aboard OceanXplorer as an ROV pilot navigates ROV Chimaera.
Conducted in collaboration with Minderoo Foundation, Minderoo OceanOmics Centre at UWA, the Western Australian Museum, and the Living High Seas Initiative, the expedition surveyed two seamount features within Roo Rise. One lies within the South of Java Island Ecologically and Biologically Significant Marine Area [EBSA], while the other is located near its southwestern boundary. Researchers from the Nanyang Technological University, Singapore also participated in the expedition.
The research team used high-resolution seafloor mapping and remotely operated vehicle [ROV] surveys to document the structure and biodiversity of the two features. Environmental DNA [eDNA] sampling, water-column profiling, plankton surveys, and targeted specimen collection produced complementary datasets spanning the seafloor through the upper ocean.
Expedition outputs include:
- 12,833 square kilometers of seabed mapped, including 9,333 square kilometers in international waters. Approximately 8,232 square kilometers, or 64 percent of the total area, represents new mapping when compared with existing global and Australian datasets.
- Eight ROV dives, one submersible dive, nine CTD casts, 15 bongo net deployments, and six XBT deployments. The deepest CTD cast reached 3,845 meters.
- 2,365 samples recorded across the expedition's scientific workstreams, including 329 specimen lots and 528 eDNA samples collected across ROV transects and CTD stations.
- Tissue samples from 243 specimens across nine phyla collected for whole-genome sequencing and the development of genomic reference resources in collaboration with the OceanOmics Centre.
Preliminary observations documented extensive sponge gardens and coral communities across Roo Rise, including large habitat-forming species and taxa recognized as indicators of Vulnerable Marine Ecosystems [VMEs]. Several surveyed areas supported dense coral and sponge assemblages with diverse associated communities of echinoderms, crustaceans, molluscs, annelids, and fishes.
Scientists also identified four xenophyophore morphotypes that may represent undescribed species, subject to further taxonomic and molecular review. An unusual seafloor habitat consisting of probable early diagenetic carbonate colonized by abundant agglutinated foraminifera was documented during a Roo Rise dive.
"Roo Rise sits within a region that is globally important for ocean productivity and fisheries, yet its deep-sea habitats have remained largely under-characterized," said Dr. Alexis Weinnig, Science Program Manager and Expedition Coordinator at OceanX. "Over the past 22 days, our team mapped the structure of these seamounts and documented deep-water communities. We also collected samples from the seafloor through the water column. Bringing these datasets together will give scientists and decision-makers a stronger evidence base for understanding this part of the high seas."
The South of Java Island region is shaped by seasonal upwelling and complex oceanographic processes. It is also associated with the only known spawning area for endangered Southern Bluefin Tuna, although this expedition took place outside the species' peak spawning season. The data collected will help scientists examine how seafloor structure, water-column conditions, and biological communities interact across this productive open-ocean ecosystem.
Minderoo Foundation and Minderoo OceanOmics Centre at UWA led environmental DNA sampling and associated tissue sample collections in support of genomic biodiversity research across the expedition. The ship-based program generated 528 eDNA samples from ROV transects and CTD stations, while representative tissue samples from 243 specimens collected in situ via ROV dives will support whole-genome sequencing and the creation of genomic reference resources. At Christmas Island, an adjacent marine protected area under Australia's jurisdiction, eDNA samples were collected from 90 sites, including 20 locations revisited from a 2023 survey.
"This expedition lays the groundwork to support genomics-based biodiversity monitoring in one of the ocean's most under-studied and difficult-to-reach regions. By combining eDNA and tissue samples from Roo Rise with our growing datasets from Christmas Island, we can compare biodiversity across a...