Deciphering the life adaptation in extreme high pressure: Genomic breakthroughs and ecological insights in fish from hadal zone
On March 6, 2025, the prestigious journal Cell published a special issue comprising three research papers led by Chinese scientists systematically depicting biodiversity in Earth’s deepest ecosystems. This landmark achievement utilized China’s independently developed deep-sea exploration vehicles, including the manned submersible “Shenhai Yongshi (Warrior in deep-sea),” “Fendouzhe (Striver),” the full-ocean-depth lander “Yuanweishiyan” and “TIAN YA” to comprehensively analyze microbial, invertebrate, and vertebrate communities within hadal ecosystems, including the Mariana Trench. This research provides an unprecedentedly comprehensive view of life adaptation strategies in environments deeper than 8,000 m (Figure 1). The vertebrate-focused study particularly explores the complex adaptive mechanisms—genomic, biochemical, and ecological—that enable fish to thrive in extreme hadal environments, significantly advancing our understanding of life’s evolutionary limits, revealing unexpected ecological connectivity in hadal ecosystems, and highlighting human impacts on these remote ecosystems, emphasizing the urgency of marine conservation.
Hadal zones are among Earth’s most extreme habitats, characterized by immense hydrostatic pressures (hundreds of atmospheres), near-freezing temperatures, complete darkness, and scarce food availability, posing significant challenges to vertebrate surviva Traditionally, scientific consensus held that deep-sea vertebrate adaptation primarily involves osmolytes such as trimethylamine N-oxide (TMAO) to stabilize protein structures under extreme pressures. However, this study performed detailed genomic sequencing, metabolomics, and ecological analyses on 11 deep-sea fish species collected from diverse locations ranging from the Western Pacific to the Central Indian Ocean, including hadal trenches, abyssal basins, fracture zones, hydrothermal vents, and the South China Sea. The findings indicate significantly more diverse and complex adaptation strategies than previously assumed, including gene regulation, metabolic adjustments, ecological specializations, and behavioral adaptations.
This research constructed an evolutionary “tree of life” for deep-sea fishes, revealing a complex evolutionary history of vertebrate colonization of the hadal zone. Phylogenetic analyses suggest a dual evolutionary path characterized by “ancient survivors” that adapted to deep-sea habitats around 100 million years ago and “recent colonizers,” which entered deep-sea environments after the Cretaceous-Paleogene mass extinction event approximately 65 million years ago.
