Hydrothermal Vents Found in the Icy Depths of the Remote South Sandwich Islands 

An Ocean Census Flagship expedition and GoSouth team of scientists found suspected new species, discovered one of the island chain’s shallowest hydrothermal vents, and explored the deepest trench in the Southern Ocean. 

Palo Alto, CA, USA — An international team of scientists on a recent 35-day deep-sea expedition to one of the most remote island chains in the world observed thriving polar ecosystems, discovered new hydrothermal vents, coral gardens, and many suspected new species. The Ocean Census Flagship expedition aboard Schmidt Ocean Institute’s research vessel Falkor (too) explored the South Sandwich Islands, including one of the coldest and most isolated submarine trenches on the planet, and also found evidence of explosive volcanism. This was the same expedition that filmed the first confirmed sighting of a juvenile colossal squid.

The expedition was part of the Nippon Foundation–Nekton Ocean Census program, the world’s largest initiative to accelerate the discovery of ocean life. The Ocean Census scientists led the species discovery efforts, uncovering a wide range of potentially new marine life — including corals, sponges, snails, sea urchins, benthic ctenophores, and sea stars. The exact number of new species will be announced later this year following an Ocean Census workshop, where taxonomic experts will formally assess and catalog the findings. The GoSouth team — a collaboration between the University of Plymouth (UK), GEOMAR (Germany), and the British Antarctic Survey (UK) — investigated the effects of geohazards, including tsunamis, volcanoes, and earthquakes.

“This expedition has given us a glimpse into one of the most remote and biologically rich parts of our ocean. This is exactly why the Ocean Census exists — to accelerate our understanding of ocean life before it’s too late,” said Dr. Michelle Taylor, head of science and expedition principal investigator at the Ocean Census, and senior lecturer at the University of Essex. “The 35 days at sea were an exciting rollercoaster of scientific discovery; the implications of which will be felt for many years to come as discoveries filter into management action.”

Mother Nature threw everything she had at the expedition, said Taylor, including a subsea earthquake, tropical storm force winds with hurricane-level gusts, eight-meter (26-foot) waves, and icebergs to navigate.

Located in the South Atlantic, the South Sandwich Islands are part of a rich mosaic of geologic features such as hadal zone trenches, underwater volcanoes, and spreading centers — features created by tectonic forces that have supported the evolution of species found nowhere else on the planet. It took eight days for the research vessel to travel to the islands from the port of Punta Arenas, Chile.

The GoSouth team, led by Co-Chief Scientist Dr. Jenny Gales, discovered two pockmarks in the mapping data of an underwater caldera — a bowl-shaped depression in the seafloor, left after a volcano erupts. Pockmarks can indicate hydrothermal activity. Using a “nested” approach, the team deployed Schmidt Ocean Institute’s remotely operated vehicle, SuBastian to map the pockmarks at a higher resolution and confirm the presence of vents.

The larger pockmark contained three hydrothermal vents, and the smaller contained one. Located at 700 meters depth (nearly 2300 feet), they are one of the shallowest hydrothermal vents to have been discovered near the South Sandwich Islands, and the only ones to be explored using a remotely operated vehicle. The tallest vent chimney was four meters (13 feet), making it about as tall as a basketball hoop. Each vent was covered with an array of life dependent on chemosynthesis, including sea snails and barnacles. Thriving coral gardens and large sponges were found in close proximity to the vents — an unusual observation, said Taylor.

“Discovering these hydrothermal vents was a magical moment, as they have never been seen here before,” said Gales, an associate professor in Ocean Exploration at the University of Plymouth (UK). “It’s an incredible discovery that provides valuable insights into the area’s tectonic activity. Making such a discovery is rare. It highlights the importance of ocean exploration and seafloor mapping.”

In addition to the vents, other notable observations during the expedition included:

• In the trench, scientists found snailfish eggs that had been laid on a black coral, as well as a potential new sea cucumber species;
• large pumice blocks, indicating that the South Sandwich Islands are capable of explosive volcanism; 
• a vibrant coral garden located west of Saunders Island at a depth of 120 meters (394 feet); 
• Capturing the first footage of Akarotaxis aff. gouldae, a species of dragonfish that was discovered two years ago.

“The challenging ocean and weather conditions and the isolated location of the South Sandwich Islands capture the imagination of the boldest explorers — often the closest humans to the vessel were on the International Space Station,” said Schmidt Ocean Institute’s Executive Director, Dr. Jyotika Virmani. “We are proud to have collaborated with Ocean Census in their mission to advance the discovery of marine life and GoSouth in their quest to better understand the geological nature of this dynamic corner of the world.” 

Image Credit: Jialing Cai / The Nippon Foundation – Nekton Ocean Census / Schmidt Ocean Institute

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About the Organizations:

By Rodney V Salm

Rodney Salm takes us on a 55-year journey that began as a boy in Moçambique through a life of extreme adventure spent in and under the ocean in polar regions and tropical seas, but principally among coral reefs in far-flung places. He chronicles his transition from plundering seas to conserving their precious bounty.

In those early years when there were no rules and the resulting freedom liberating, Rod drew heavily on self-reliance built from camping in the bush and along beaches. He learned to live off the sea, often sharing his speared fishes with sharks that harassed him as he hunted for his next meal.

During the first decades of his career, Rod worked alone under the seas and across deserts in foreign lands, learning his limits, encountering danger, and checking off another of his nine lives. This lifestyle exposed him to adventure and discovery, different people and beliefs systems, and engaging legends. In his own words: “I fell inextricably in love with the underwater world, especially corals, and came to realise that the damage done to them by humans around the world is not necessarily fatal or final. Coral reefs are vital living organisms, well able to recover from most harm humans and the climate can do to them. They just need to be given the chance.” That theme lies at the core of the enthusiasm and messages Rod shares in this book.

Crammed with adventure, pioneering conservation achievements, and field science, Rod chronicles the many challenges that often plagued but never deterred him. Even as heat stress resulting from global warming caused mass coral bleaching and mortality and confounded reef managers and scientists, he led the charge to find ways to address the issue. Again, in his own words: “In 1989 Oman was where the seed of reef resilience was planted in my mind. In 1998 Kenya and Seychelles were where it was watered. And in 1999 it germinated in Palau.” The result was adoption of resilience as an organising principle for coral reef conservation, first in Palau and over time around the world.

The book concludes with a firsthand account of Rod’s development of a groundbreaking method for rapid assessment and enhancement of coral health and resilience to address the challenges of climate change.

Combining vivid storytelling with practical insights, the book aims to inspire scientists, students, and nature enthusiasts—showing that science can be thrilling, adventurous, and impactful. It leaves us optimistic that we can take action to safeguard coral communities and enhance their resilience to global change.

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About the Author
Rodney V Salm

Although now officially retired, I continue to pursue practical methods for the application of resilience principles to coral conservation. I am a member of the scientific advisory board of the Coral Triangle Center and emeritus adviser to The Nature Conservancy Micronesia Marine Program. In recent years I led a coral health and resilience assessment for African Parks in the Bazaruto Archipelago Nature Reserve in Mozambique.

On April 4th and 5th, 2025, I visited the Reserva Provincial Cabo Vírgenes (Pinguinera) in Patagonia, which is, to my knowledge, a protected area serving as a breeding colony for Magellanic penguins.

I was shocked to find countless dead penguins around the fenced area and along the beach. The live animals that remained appeared very frightened.

I wonder what could be the reason for such a mass death. There were both old and young penguins—some seemed to have died only recently, while others were already more or less mummified or reduced to skeletons.

It was, in fact, a very sad and shocking sight.

We saw that there were large methane gas extraction plants in the immediate vicinity of the breeding colony, and drilling rigs a little further out to sea.

I read in a publication dated 2007 that there was another incident in this region following an oil spill: https://delfinaustral.com/mar_limpio/publicaciones/EOW07%20VRuoppolo-3%20Cabo%20OK%201.pdf

However, from what I could see, the penguins were not oiled.

I also found a bullet casing on the beach, alarmingly close to the penguin remains. One penguin appeared to have been struck in the head with a rock, lying in a position that suggested trauma. While it’s impossible to draw immediate conclusions, the presence of a bullet casing and signs of injury raise unsettling concerns that some of these deaths may not have been natural.

I have already contacted several organizations, including the Consejo Agrario Provincial de Santa Cruz (CAP), IFAW, and Fundación Vida Silvestre Argentina.

There is an urgent need to understand the reasons for this mass die-off and to find a solution that will not endanger the lives of the remaining Magellanic penguins.

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