Expedition dates: Feb. 24 – Apr. 4, 2024

The Salas y Gómez Ridge extends off the coast of Chile to Rapa Nui, also known as Easter Island, in the Central Pacific. Created by volcanism, these underwater mountains provide essential habitats for deep-sea organisms, supporting some of the highest marine endemism globally. Many of the species living here exist nowhere else on Earth. The hard, rocky surface offers something solid for sessile life to cling to, and the mountainous landscape provides animals a place where food is delivered directly to their benthic doorsteps by the water currents. 

Extending off the coast of Chile, 73% of this remote, underexplored region lies in the high seas, outside of any country’s jurisdiction. The Salas y Gómez Ridge likely harbors pristine and unexploited habitats with abundant biodiversity that require international cooperation to protect before they are lost.  

To better understand the biodiversity and connectivity of the region — how organisms living along this ridge reproduce, mature, and move via ocean currents — Dr. Erin E. Easton of the U.S. University of Texas Rio Grande Valley has assembled an international and multidisciplinary team to examine an understudied, and essential area of the global Ocean. Together, they will explore these southeast Pacific seamounts via a forty-day expedition that harnesses the technology and powerful data tools available on R/V Falkor (too). The team intends to assemble critical information to describe the region and support the designation of one of the first high-seas marine protected areas along the Salas y Gómez Ridge. 

Understanding seamount biodiversity

Experts believe the ridge provides a protective corridor for numerous organisms traveling between the central Pacific and the South American coast, and the area almost certainly harbors species new to science. Marine mammals and seabirds migrate across the ridge to feed. This region harbors 82 threatened or endangered species, and there is strong evidence that biodiversity along these seamounts warrants robust protections.

The connections and environmental drivers between the seamounts of the Salas y Gómez Ridge are understudied. A key objective of this expedition is to identify biogeographic boundaries at different scales. The team will examine how currents flowing between and around the mountains impact the distribution of vital food sources and the genetic diversity among the organisms living there. Their work will inform future conservation efforts and advance our understanding of oceanic processes around seamounts.

People and science at sea

The international, multidisciplinary team includes engineers, marine ecologists, and physical, geological, chemical, and biological oceanographers, half of whom come from Chilean scientific institutions. The Rapa Nui Sea Council (koro Nui o te Vaikava) elected Artist-at-Sea Tauroa Aguilera and Berth of Opportunity participant Serafina Moulto to join the expedition to bring their perspectives as Rapanui community members to the expedition.

To better assess the biodiversity and oceanic processes, the team will collect multibeam and backscatter data to generate maps of ridges and identify locations for exploration with the ship’s remotely operated vehicle, ROV SuBastian. They’ll also collect meteorological, acoustic, and oceanic data while surveying surface waters for seabirds, marine mammals, and marine debris. Water samples collected with the ship’s CTD rosette and baited traps will allow the scientists to look at productivity in the water column and compare that to wildlife sightings above and deep below the Ocean’s surface.  

Video surveys and sampling with the ROV dives in three depth zones (<600, 600-1000, and 1000-1500 m) will help scientists describe what sort of animals and organisms exist along these seamounts and within potential biogeographic boundaries. Holotypes, the single physical examples of an organism used when the species is formally described, will remain at the Chilean National History Museum to build capacity for future scientific study and advocacy efforts in the region.

A stereo, laser, and hyperspectral camera system, currently under development and testing, will be integrated onto the ROV. The camera will allow the team to capture color arrays invisible to the human eye within each image pixel. The minute color differences will enable the identification of tiny organisms, different types of sand, and potentially whether or not animals are healthy or sick.  Together, this data and imagery will paint a detailed portrait of biodiversity on the ridge.

Informing a high-seas marine protected area

In February of 2023, the United Nations adopted the High Seas Treaty and pledged to protect 30% of the world’s Ocean by 2030. Currently, less than 1% of the high seas are protected. While recent marine protected areas, or MPAs, have been established in Chile, they are limited to the country’s territorial waters. Rapa Nui leadership and Chilean policymakers have championed international efforts to designate the ridge as a large-scale marine protected area. Previous studies strongly suggest that the Salas y Gómez Ridge is a critical area to protect in international waters, and this expedition will provide solid evidence to support and advance this effort. 

Furthermore, because there is little to no fishing or commercial activity around the ridge, scientists and policymakers are optimistic that it is a bastion for oceanic biodiversity.  Due to the lack of human exploitation,  a small window of opportunity exists for protecting the Salas y Gómez Ridge without impacting industry, which could galvanize support for international cooperation to preserve the ridge for future generations. 

Erin Easton (Chief Scientist, University of Texas Rio Grande Valley) pictured in Mission Control during the first dive of the expedition.
ROV SuBastian is brought back on board.
A mastigoteuthis, or whip-lash squid, squirting ink.
A lavandar-colored, deep-sea coral with a shrimp associate.
A giant hydroid with a scale worm living on it.
Francisca Oyanadel (Student, Universidad Católica del Norte) examines a coral sample in the Main Lab.

Cruise Log

No cruise log entries at this time.

Data & Publications

Live ROV Footage