Unveiling the Lost Living Fossil Ecosystems of the Atacama Trench

This project sought to explore the Atacama Trench and continental slope off northern Chile to test the hypothesis that the region hosts ancient “living-fossil” benthic ecosystems composed of invertebrates, microorganisms, and viruses that have persisted in relative isolation for millions of years. Motivated by previous discoveries of unusual Atacama microorganisms and marine invertebrates previously known mainly from the fossil record, the team aimed to determine the diversity, evolutionary history, energy sources, and ecological relationships of these deep-sea communities, while evaluating them as analogs for potential ecosystems in the subsurface oceans of Europa and Enceladus. To accomplish this, an international team conducted a multidisciplinary investigation of the Atacama continental slope, focusing on sites where ancient brachiopods, mollusks, and other “living fossils” had previously been found. The study combined deep-sea exploration, specimen collection, DNA barcoding, microbial sequencing, geochemical analyses, and methane seep characterization to identify new species, reconstruct their evolutionary histories, and understand the environmental processes sustaining these ecosystems. The project was expected to generate new biological collections, reveal previously undescribed organisms, improve knowledge of deep-sea biodiversity, and provide valuable analog models for astrobiology and the search for life beyond Earth.