New research reveals methane-free ecosystem in the Peru-Chile trench, discovering unique microorganisms that challenge the limits of life as we know it. This finding offers fresh perspectives for astrobiology and the study of extreme habitats on Earth.
Led by the Centro de Astrobiología (INTA-CSIC), the study has identified a biological system in which sulfur, not methane, is the protagonist, at a depth of 2.5 kilometers. This phenomenon challenges traditional theories about submarine emissions and expands the known conditions for the existence of life.
The Peru-Chile trench has revealed a deep ecosystem where alternative chemical processes, in the absence of methane, have implications for climate science and the search for extraterrestrial life.
Instead of methane, the microorganisms in this area use sulfur oxidation and reduction processes for sustenance, creating a self-sufficient chemical engine that supports complex life without the need for sunlight or organic matter.
Methane-free ecosystem
This discovery changes the paradigm of “cold seeps,” traditionally associated with hydrocarbons like methane. In an area near Antofagasta, at a depth of 2.5 kilometers, scientists have detected a methane-free environment that challenges the energy bases of these ecosystems.
The microbial diversity discovered suggests alternative metabolic pathways that have not been seen with such intensity in similar environments. The geological stability of this region, maintained over millions of years, may have favored the evolution of unique biological communities.
RNA studies have revealed microbial communities dominated by sulfur cycles, with oxidizing bacterial biofilms on the surface and sulfate-reducing microorganisms in the subsurface.
The sulfur cycle in this ecosystem acts as the main energy source, replacing methane and generating sufficient energy flows to sustain complex communities under extreme conditions.
The pyrite formations found in the sediment confirm intense geochemical activity, a product of microbial activity that alters the chemical environment.
The absence of typical microorganisms like ANME archaea, which consume methane, indicates a shift in the trophic chain and suggests an ecosystem based on sulfur instead of reduced carbon.
This autonomous ecosystem, independent of surface organic matter, becomes a unique case within the deep oceans. Its biological configurations open new lines of research on metabolic diversity.
The discovery has implications for the search for life on other planets, suggesting that moons like Europa or Enceladus could harbor similar ecosystems. The observed biological resilience exceeds known limits and offers adaptation strategies in environments without conventional energy resources.
The Peru-Chile trench, with more than 8,000 meters of depth, is one of the most stable places on Earth, allowing the persistence of ecosystems that could be considered “living fossils.”
