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 these animals most extreme habitats on the planet: hydrothermal vents on the sea floor. More specifically, the Capelinhos hydrothermal structure, located in the northern part of the Mid-Atlantic Ridge off the Azores.
These areas of the seafloor are located in areas of intense volcanic and magmatic activity, called ridges, where new oceanic crust is forming. At these sites, seawater penetrates the seafloor, reacts chemically with hot rocks and reaches temperatures of up to 400 °C before being expelled as hydrothermal fluid, a process similar to that of terrestrial geysers. This discovery was published in the journal Scientific reports.
The specialized fauna colonizes these hostile habitats thanks to the presence of microorganisms capable of generating energy from chemical compounds in liquids, rather than using solar energy like the vast majority of primary producers.
A very inhospitable hydrothermal building
Capelinhos contrasts with the hydrothermal sites in the Lucky Strike field in that it has a more acidic environment (low pH) and higher concentrations of metals, particularly iron. Given the potential toxicity of these fluids, scientists assumed they would find less diversity and different species than in surrounding buildings. Surprisingly, they discovered a very rich ecosystem in which several species live Crustaceans, molluscs and worms in the sea, resulting in a faunal composition similar to that of other buildings with less extreme conditions.
The Capelinhos building was recently discovered and this study is the first to describe its fauna
Remarkable differences have been observed in the food resources and biochemical processes that allow these animals to obtain the energy necessary for their survival. Rather than the predominant hydrogen sulfide oxidation processes in other hydrothermal ecosystems, the data collected in this study suggest a more important role for hydrogen sulfide methane.
The results of this research, published in the journal Scientific reports, highlight the great ecological and trophic plasticity of the fauna of hydrothermal vents. They also confirm the important role of the mussel Bathymodiolus azoricus in animal communities. In fact, this “technical” way induces small turbulences that improve the dilution of metal-rich liquids with seawater, reducing their concentrations in the environment and so on complex habitat This allows the installation of a diverse associated fauna despite severe environmental constraints.
Joan Alfaro LucasLead author of the study, currently at the University of Victoria in Canada, comments: “The Capelinhos building was recently discovered and this study is the first to describe its fauna. Our previous knowledge of the chemistry of its fluids got us thinking.” This would be a very inhospitable building, even for the specialized fauna of these environments. The fact that these organisms can live in Capelinhos is surprising, but even more so when you consider it They use completely different resources to the fauna of the neighboring buildings. However, this makes sense from an ecoevolutionary point of view, as hydrothermal fauna can colonize new habitats and thus maintain populations that ensure their viability in these extreme and dynamic ecosystems.”
In the face of significant environmental changes, which can even lead to extreme conditions, there will always be life forms capable of adapting, living and thriving.
Another author, Daniel MartinCEAB-CSIC researchers, emphasizes: “Our study not only provides information about the still poorly understood richness and abundance of life in the ocean depths, but also highlights the enormous diversity of some marine organisms. In the face of major environmental changes, which may even lead to extreme conditions, there will always be life forms capable of adapting, living and thriving.”
Jozee Sarrazina benthic ecology researcher at Ifremer who initiated this study emphasizes: “Our results 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 hydrothermal vents give life to the hydrothermal fauna and also produce mineral deposits of interest to industry. The potential exploitation of these deposits would have impacts, still poorly understood, on this fauna, whose exceptional adaptive abilities are now proven. Without a deep understanding of how these ecosystems function, no exploitation makes sense.
Researchers have approached the study of the metabolism of the organisms that live in these extreme environments from a different angle; a metabolism that seems to be quite flexible. This opens up new opportunities to explore the incredible ability of living things to generate the energy they need to live. By not having to rely on a specific food source, the range of successfully colonized environments expands.
Reference:
Jozee Sarrazin. “Fluid chemistry changes the trophodynamics of the fauna, but not the composition of the Capelinhos deep-sea hydrothermal edifice.” Scientific reports.