Surviving and Thriving in One of Earth’s Most Hostile Environments

Over 9,500 meters of ecosystems fueled by chemicals from tectonic plate interactions have been uncovered beneath the northwest Pacific Ocean.

“Their resilience and beauty captivated me,” says Mengrand Du from the Chinese Academy of Sciences in Sanya. “The striking crimson tentacles unfurl like delicate blossoms of the trench.”

Du and her team undertook 24 dives between July 8 and August 17, 2024, exploring 2,500 kilometers west of the Krill Kamchatka trench and Aleutian trench, at depths ranging from 5,800 to 9,533 meters. In a frozen section beyond 6,000 meters deep, the Hadal zone experiences crushing pressure and is devoid of light.

This region is referred to as the Hadal biosphere, which derives energy from nutrients descending from surface photosynthesis or exists via chemical bonds relying on chemicals as energy sources.

Taxonomic and genetic data gathered during the dives indicated that many organisms in the Hadal zone utilize compounds such as hydrogen sulfide and methane, which are released through fault lines formed as tectonic plates slide against each other.

“We have discovered a chemically-synthesized community thriving at an astonishing depth of 9,533 meters,” Du states. These findings, made during 19 dives, illustrate their extensive distribution.

The chemically-driven community was primarily composed of bivalve mollusks and marine tube worms known as ciboglinid polychaetes. Some populations consisted of thousands of individuals, sprawling for kilometers.

A notable characteristic of many of these organisms is their dependence on chemical energy rather than sunlight, according to Du. “While other organisms, such as sea cucumbers and amphipods, might inhabit greater depths, they cannot harness chemicals like hydrogen sulfide for energy and must rely on organic matter instead.”

This finding indicates “the deepest and most extensive known chemical synthesis community on our planet.”