New hydrothermal vents and coral gardens found in the icy depths of the remote South Sandwich Islands

Dr Jenny Gales was part of an international team of scientists who spent 35 days exploring the Southern Ocean
Scientists - including Dr Jenny Gales - observed shimmering hot water emerging from a chimney at 710 meters during dive 804 on the north-east side of Quest Caldera; they located the hydrothermal vent by focusing on previously recorded heat anomalies and pockmarks in the mapping data
ROV SuBastian / Schmidt Ocean Institute
Scientists observed shimmering hot water emerging from a chimney at 710 meters during dive 804 on the north-east side of Quest Caldera
An international team of scientists, including a researcher from the University of Plymouth, has discovered new hydrothermal vents, coral gardens and many suspected new species on an expedition to one of the most remote island chains in the world.
Dr Jenny Gales was part of the Ocean Census Flagship expedition, a 35-day deep-sea voyage aboard Schmidt Ocean Institute's research vessel Falkor (too).
It explored the seas around the South Sandwich Islands, researching one of the coldest and most isolated submarine trenches on the planet, while also finding evidence of explosive volcanism.
The expedition – which also captured the first confirmed sighting of a juvenile colossal squid – was part of the Nippon Foundation–Nekton Ocean Census program, the world’s largest initiative to accelerate the discovery of ocean life.
As part of that, the GoSouth team – a collaboration between the University of Plymouth, the University of Essex, GEOMAR, and the British Antarctic Survey – investigated the effects of geohazards, including tsunamis, volcanoes, and earthquakes.
Dr Jenny Gales (Principal Investigator, University of Plymouth) and Andrea Verolino (Scientist, Nanyang Technological University) process push cores full of seafloor sediment in the hangar. These samples will lend insight into geological forces and historical changes at play in the area Alex Ingle / Schmidt Ocean Institute
Dr Jenny Gales helps to process push cores full of seafloor sediment in the hangar. These samples will lend insight into geological forces and historical changes at play in the area
Led by Dr Gales, Associate Professor in Hydrography and Ocean Exploration at the University of Plymouth and the expedition’s co-chief scientist, the GoSouth team 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 and 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 700m deep below the surface, 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 4m, and each vent was covered with an array of life dependent on chemosynthesis, including sea snails and barnacles, with thriving coral gardens and large sponges found in close proximity to the vents.

Discovering these hydrothermal vents was an absolutely magical moment, as they have never been observed by humans before.

When the first vent came into view, we couldn't fully believe it and there were shouts of collective joy across the team. It's an incredible discovery that will completely change our understanding of geohazards and ecosystems across the region. Making this kind of discovery is very rare, but it highlights the importance of ocean exploration and seafloor mapping - without the high-resolution mapping technologies on the remotely operated vehicle, we wouldn’t now be in this position.

Jenny GalesDr Jenny Gales
Associate Professor in Hydrography and Ocean Exploration

Remotely Operated Vehicle SuBastian is recovered to the Research Vessel Falkor (too) after a dive. A multidisciplinary, international team of scientists - including Dr Jenny Gales - recently returned from an expedition to the South Sandwich Islands, one of the most remote island chains in the world. Using ROV SuBastian, they observed thriving polar ecosystems, discovered new hydrothermal vents, coral gardens, and many new species. They also found evidence of explosive volcanism in the area. Alex Ingle / Schmidt Ocean Institute
Researchers - including Dr Jenny Gales - discovered hydrothermal vents at 700 meters depth (nearly 2300 feet) on the northeast side of Quest Caldera, off the South Sandwich Islands. The tallest vent chimney was four meters (13 feet), and they were was covered with an array of life, including sea snails and barnacles ROV SuBastian / Schmidt Ocean Institute
In the control room of Research Vessel Falkor (too), Chief Scientist Michelle Taylor (University of Essex) and Scientist Tea Isler (Alfred Wegener Institute) marvel at a massive coral — potentially over a thousand years old — spotted during a Remotely Operated Vehicle (ROV) dive on the northeast side of Quest Caldera, off the South Sandwich Islands. This was observed during an expedition co-led by Dr Jenny Gales Alex Ingle / Schmidt Ocean Institute
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 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.

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. 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.

Dr Michelle Taylor
Head of science and expedition principal investigator at the Ocean Census, and senior lecturer at the University of Essex 
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 centres – 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, during which time they encountered a subsea earthquake, tropical storm force winds with hurricane-level gusts, 26ft waves, and icebergs.

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. 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.

Dr Jyotika Virmani
Executive Director, Schmidt Ocean Institute
 
 

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