Scientists reveal pristine ecosystems on high seas seamounts

Scientists reveal pristine ecosystems on high seas seamounts

An international expedition to the Salas y Gómez Ridge has uncovered 160 species, potentially including 50 new to science. Led by Dr Erin E. Easton and Dr Javier Sellanes, the team utilized innovative hyperspectral camera technology to explore this biologically rich region. Their findings underscore the urgent need for conservation efforts in the area, especially with the potential establishment of a high seas marine protected area.

The observed species consist of squid, fish, corals, molluscs, sea stars, glass sponges, sea urchins, crabs and squat lobsters, among others. Additionally, the team set a record for sighting the deepest-known photosynthesis-dependent animal in the world: a Leptoseris, commonly known as a wrinkle coral. The expedition follows a scientific research cruise in January, which primarily investigated the Nazca and Juan Fernandez Ridge seamounts and found 100 suspected new species.

Distinct ecosystems

The findings come after a team of scientists completed a 40-day research expedition across the Salas y Gómez Ridge to Rapa Nui, also known as Easter Island. The ridge lies off the coast of Chile and is a biologically rich region under consideration for a high seas marine protected area designation. The research team, led by Erin E. Easton of the University of Texas Rio Grande Valley and Javier Sellanes of the Universidad Católica del Norte, closely examined ten seamounts and two islands on the 2,900km-long oceanic mountain range. They determined that the individual seamounts harbour distinct ecosystems such as glass sponge gardens and deep coral reefs. The information collected during this expedition will provide the scientific basis to inform the management of existing marine protected areas and potentially expand them, especially around the island of Rapa Nui. Koro Nui o te Vaikava, the Rapa Nui Sea Council, collaborated with the science team on the expedition. The council is the co-administrator of Chile’s most remote territorial seas and Rapa Nui’s marine protected area. It may assist in managing the Salas y Gómez high seas marine protected area, should it be established.

“The observation of distinct ecosystems on individual seamounts highlights the importance of protecting the entire ridge, not just a few seamounts,” said chief scientist Dr Erin E. Easton of the University of Texas Rio Grande Valley. “We hope that the data collected from this expedition will help establish new marine protected areas, including on the high seas on the Salas y Gómez Ridge.”

The Salas y Gómez Ridge is one of several global locations under consideration for designation as a high seas marine protected area upon ratification of the UN High Seas Treaty. Parts of the ridge within Chile’s national jurisdiction are protected; however, much of the ridge lies in international waters. While many countries, including the United States, have signed the treaty, only Chile and Palau have ratified it. Once 60 nations ratify the treaty, countries can establish marine protected areas in international waters with sufficient scientific data.

Not yet documented

The Salas y Gómez Ridge comprises over 110 seamounts and supports the migration of animals such as whales, sea turtles, swordfish, tuna and sharks. During the expedition, 78,000 square kilometres were mapped, including six seamounts not yet documented in hydrographic surveys.

“The astonishing habitats and animal communities that we have unveiled during these two expeditions constitute a dramatic example of how little we know about this remote area,” said Dr Javier Sellanes of the Universidad Católica del Norte. “These expeditions will help alert decision makers to the ecological importance of the areas and contribute to strengthening protection strategies within and beyond jurisdictional waters.”

Much of the expedition occurred around Rapa Nui, near the ridge’s western end. The science team on the expedition explored waters adjacent to the island and spent a day making a cultural exchange visit. Four Rapa Nui community members, including a member of the Rapa Nui Sea Council, participated in the expedition alongside scientists from Chile, the United States, Italy, Spain and the Netherlands.

Research and exploration

“The importance of participating in an oceanographic scientific expedition for Rapa Nui lies in the opportunity to know and better understand the marine environment surrounding the island,” said Marcela Heys, observer and Rapa Nui Sea Council member. “Natural resources, unknown marine species and climate phenomena that directly affect the community can be discovered through research and exploration.”

This was the second expedition for Schmidt Ocean Institute’s RV Falkor in Chile. During the expedition, engineers tested new camera technologies, including a hyperspectral and stereo camera system developed by MBARI (Monterey Bay Aquarium Research Institute). The engineers hope to scale these low-cost technologies to better support biodiversity surveys on the seafloor.

“The international team on board Falkor undertook a long voyage to shed light on this major, yet little mapped underwater mountain range in the South Pacific and its diverse ecosystem,” said Schmidt Ocean Institute executive director Dr Jyotika Virmani. “Schmidt Ocean Institute supports engineers developing novel technologies and the new cameras tested added immense detail and more easily showed the incredibly vibrant colours.”

Giancarlo Troni, principal engineer at the Monterey Bay Aquarium Research Institute, in consultation with ROV technician Mike Rae before installing the hyperspectral camera on ROV SuBastian. (Image courtesy: Misha Vallejo Prut/Schmidt Ocean Institute)
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