A groundbreaking advancement in marine biology occurred with the identification of 38 new marine species collected from the deep waters around Japan! The research, conducted by the Nippon Foundation - Nekton Ocean Census and JAMSTEC as part of their ongoing expeditionary program, began with the examination of the Nankai Trough and Shichiyo Seamount Chain in 2025. Approximately 5,000 meters below sea level, researchers discovered the ‘Glass Castle’ comprised of the delicate silica skeletons of hexactinellid sponges. These shimmery sponges provide living space for organisms that had never been recorded before.
Using cutting-edge submersibles (manned and unmanned) and DNA sequence technology, researchers were able to evaluate an area that comprises one of the last frontiers of our planet to be evaluated for marine biodiversity - the deep sea. The results demonstrated that the complexity and abundance of life in the deep sea are far greater than anyone has ever anticipated. The study underscores the necessity for global ocean conservation as the evidence of vulnerability of these ecosystems necessitates immediate global protection. This discovery highlights the urgent need to safeguard these fragile, alien landscapes before human activity disrupts their ancient biological harmony.
How ‘Glass Castle’ sponges support a rare deep-sea ecosystem
The ‘Glass Castle’ provides the physical foundation needed to support the symbiotic relationship between hexactinellid sponges and less-known organisms. According to Ocean Census, the lesser-known organisms include polychaete worms, two species of which were discovered during this study: Dalhousiella yabukii and Leocratides watanabeae. The benefits provided by the sponges (protection) have resulted in the establishment of an incredibly rare and delicate invertebrate community exhibiting the ability to survive at great depths.
How DNA sequencing identified 38 new species
According to the study published in JAMSTEC, the team used the Research Vessel Yokosuka and the Shinkai 6500 submersible to explore depths down to 5,000-meters under water. They used ‘cyber-taxonomy,’ which combines rapid DNA sequencing with high-resolution imaging, to quickly establish that they located 38 new species within a few weeks instead of the years that would typically be required for that kind of classification. They were able to explore five previously unilluminated volcanic peaks and abyssal trenches.
Why these specimens are changing marine science
This mission was part of a larger effort to close the taxonomic gap. Scientists found they recorded five times more species of biodiversity in the area of these specific Japanese abyssal trenches than previously documented. In addition to the 38 new species found, the team also collected over 500 total organisms, as noted in Ocean Decade; many of those specimens are still being analysed through genomic sequencing. Studies like this are important for discovering how forms of life exist in extreme conditions of pressure and total darkness.
How life coexists inside glass sponges
They looked specifically at how species living in the abyss interacted with each other. The investigators observed a variety of previously unknown worms and crustaceans that only live within the interior of glass sponges, which indicates a high degree of specialised evolutionary function. These organisms have adapted to live under the immense pressure of the Nankai Trough by establishing very close biological relationships with one another, whereby sponges afford them shelter and, in return, they may perform nutrient recycling or scavenging-related activities for the sponges.
