Hydrothermal fauna: a multidisciplinary scientific team from the University of Victoria (Canada), Ifremer (France), the University of Liège (Belgium) and the Center for Advanced Studies of Blanes (CEAB-CSIC) studied the fauna of one of the most extreme habitats on earth: loose hydrothermal vents on the seabed. More specifically, that of Capelinhos hydrothermal buildinglocated in the northern part of the Mid-Atlantic Ridge off the Azores.
These parts of the seafloor are located in areas of intense volcanic and magmatic activity, called ridges, where new oceanic crust is forming. In these places, seawater penetrates the seabed, reacts chemically with hot rocks and reaches temperatures of up to 400°C before being emitted. hydrothermal fluids, a process similar to that of terrestrial geysers. This discovery has been made published in the magazine Scientific reports.
The specialized fauna colonizes these hostile habitats, thanks to the presence of microorganisms that can produce energy from chemical compounds in liquids, instead of using solar energy like the vast majority of primary producers.
Capelinhos: a very inhospitable hydrothermal building for wildlife
Capelinhos contrasts with hydrothermal sites in the Lucky Strike field because it has a more acidic environment (low pH) and higher concentrations of metals, especially iron. Given the potential toxicity of these fluids, scientists expected to find lower diversity and different species than those in nearby buildings. Surprisingly, they discovered a very rich ecosystem, home to several species crustaceans, molluscs and worms marine, resulting in a faunal composition comparable to that of other buildings with less extreme conditions.
Remarkable differences have been observed in the food sources and biochemical processes that allow these animals to acquire the energy necessary for their survival. Instead of the hydrogen sulfide oxidation processes that are dominant in others hydrothermal ecosystemsthe data obtained in this study suggest a more important role of methane.
The results of this study, published in Magazine Scientific reportsemphasize the great ecological and trophic plasticity of the fauna of hydrothermal vents. They also confirm the important role of the mussel Bathymodiolus azoricus in faunal communities. In fact, this “technical” type causes small turbulences that enhance the dilution of liquids rich in metals with seawater, weakening their concentrations in the environment and thus creating a complex habitat allowing the installation of a diverse associated fauna despite strong ecological constraints.
Joan Alfaro Lucaslead author of the study, currently at the University of Victoria in Canada, says: “The Capelinhos Building was recently discovered and this study is the first to describe its fauna. Our previous knowledge of the chemistry of the fluids led us to think that it would be a very inhospitable building, even for the specialized fauna of these environments. The fact that these organisms can live in it Capelinhos It’s surprising, but even more so when you consider that they use completely different sources to the fauna of the adjacent buildings. However, this makes perfect sense from an eco-evolutionary point of view, as hydrothermal fauna can colonize new habitats and thus maintain populations that guarantee their viability in these extreme and dynamic ecosystems.
Another author, Daniel Martin, CEAB-CSIC researcher, emphasizes: “Our study not only provides information about the richness and abundance of life in the depths of the ocean, where so little is understood, but also highlights the enormous versatility of some marine organisms . Faced with significant environmental changes, which may even lead to extreme conditions, there will always be life forms that can adapt, live and thrive.
Jozee Sarrazin, a benthic ecology researcher at Ifremer, and who initiated this study, emphasizes: “Our findings help us better understand these unique and inaccessible environments that we need to explore more than ever. The chemical compounds present in the fluids of the hot water craterswho give life to the hydrothermal fauna, also generate mineral deposits that interest industrialists. The potential exploitation of these deposits would cause consequences that are still poorly understood in this fauna, whose extraordinary adaptability is demonstrated today. Without a deep understanding of the functioning of these ecosystems, exploitation is not reasonable.
Researchers have approached the study of the metabolism of the organisms living in these extreme environments from a different angle; a metabolism that seems to be quite flexible. This opens up new possibilities to explore the incredible ability of living things to acquire the energy they need to live. Not being dependent on a specific food source expands the range of successfully colonizable environments.