Scientists discover a new ecosystem under hydrothermal vents

8 August 2023 - EN - DE

Fig. 1: A large assemblage of tubeworms in the Fava Flow Suburbs, a site on the East Pacific Ridge at a depth of 2,500 meters. Experiments testing the theory of species dispersal through cracks in the Earth’s crust were conducted in this area. (C: Schmidt Ocean Institute)

During a research cruise, an international research team led by marine biologist Monika Bright of the University of Vienna discovered a new ecosystem in the deep sea. This is located beneath the surface of hydrothermal vents of a well-studied underwater volcano on the East Pacific Ridge off Central America. Monika Bright led the groundbreaking 30-day expedition aboard the Schmidt Ocean Institute research vessel Falkor (too) and was accompanied by an international team of scientists from the United States, Germany, the Netherlands, France, Costa Rica and Slovenia.

It has been known for over 40 years that life exists at hydrothermal vents. However, Monika Bright and her cooperation partner Sabine Gollner from the Royal Netherlands Institute for Marine Research have now made a groundbreaking observation. They discovered that animals colonize cavities in the rock beneath hydrothermal vents. The researchers thus discovered a completely unknown habitat. With the help of the underwater robot SuBastian, parts of the volcanic crust were turned upside down. The insight revealed a variety of living worms, snails and chemosynthetic bacteria that exist in water at 25 degrees Celsius. "This discovery has greatly expanded our understanding of animal life in deep-sea hydrothermal vents," Bright said. "There are two dynamic habitats in the springs. Animals above and below the surface thrive together, depending on thermal fluid from below and oxygen in seawater from above."

Fig. 2: Monika Bright examines specimens of tubeworm larvae found 2 cm deep in cracks in a rock sample. This specimen is Oasisia jerichonana, 2 mm long and probably less than a month old. (C: Schmidt Ocean Institute)

This is how the discovery of the underground ecosystem came about

Hydrothermal vents are underwater springs that form as a result of tectonic activity through cracks in the Earth’s crust. Tubeworms are the best studied animals of hydrothermal vents. However, very few of their larvae have been found in the surrounding water to date. Monika Bright then hypothesized that the larvae spread through the Earth’s crust to colonize springs from below. This thesis could now be confirmed by the sensational discovery at the Pacific Ring of Fire at a depth of 2,500 meters.

Fig. 3: The research vessel Falkor (too) at sunrise working over the Tica Vent on the East Pacific Ridge at 2,500 meters depth. Experiments testing the theory of species dispersal through cracks in the Earth’s crust were conducted in this area. (C: Schmidt Ocean Institute)

For this purpose, the scientific team conducted experiments with the underwater robot ROV SuBastian of the Schmidt Ocean Institute (SOI). Boxes were stuck over cracks in the volcanic crust and the edges sealed. When the boxes were removed after a few days and the part of the rock on which the boxes were located was pried open and turned over, the researchers were surprised to discover a large number of already adult animals.

If a new hydrothermal vents emerges, such an ecosystem can quickly establish itself, as animals can rapidly colonize the area. The observations obtained provide a strong indication of how this colonization process could take place. The data collected will be analyzed by the scientists* in the coming months. This scientific sensation sheds a completely new light on the understanding of this unique habitat.

Fig. 4: Oasisia and Riftia tubeworms and other organisms can be seen in an upside-down rock crust sample. This is a strong argument for Monika Bright and Sabine Gollner’s theory of species dispersal through cracks in the Earth’s crust. (C: Schmidt Ocean Institute)

about the expedition and participating organizations

Fig. 5: The experiments, code-named ’Mesh Box Staining Gadgets’ are sealed to the seafloor of the Flava Flow Suburbs Vents, a site on the East Pacific Ridge at a depth of 2,500 meters. These experiments tested the theory of species dispersal through cracks in the Earth’s crust. (C: Schmidt Ocean Institute)

The Schmidt Ocean Institute expedition with R/V Falkor (too) and the remotely operated vehicle SuBastian brought an international team of scientists* led by Monika Bright from the University of Vienna, funded by the Austrian Science Fund and the University of Vienna, and Sabine Gollner from the Royal NIOZ to a special volcano at 9° 50’ North on the East Pacific Rise.

The Schmidt Ocean Institute was founded in 2009 by Eric and Wendy Schmidt to promote the discoveries necessary to understand our oceans, sustain life, and ensure the health of our planet. It does this through impactful scientific research and intelligent observation, technological advancement, open information sharing, and public engagement at the highest international level. For more information, visit www.schmidtocean.org.

Fig. 6: Monika Bright and Sabine Gollner cannot hide their relief and joy when they see the result of their experiments. The remotely operated vehicle (ROV) SuBastian has turned over a piece of the Earth’s crust and revealed several young tubeworms, confirming the researchers* idea that animals can spread through cracks and caves in the rock. (C: Schmidt Ocean Institute)

NIOZ, the Royal Netherlands Institute for Marine Research, is the national oceanographic institute and the Dutch center of excellence for ocean, sea and coast. It promotes a fundamental understanding of marine systems, their changes, their role in climate and biodiversity, and how they can provide sustainable solutions for society in the future. For more information, visit www.nioz.nl.

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Translation by myScience

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