Kategorie: News
Researchers reveal amazing ecosystems in the deepest regions of the oceans
The deep sea below 6,000 meters, named after the Greek god of the underworld Hades -the Hadal zone- refers to the deepest regions of the oceans below 6,000 meters and was long considered extremely hostile to life and a largely unexplored area.
Until recently, it was assumed that only a few organisms existed there, mainly scavengers, microbes, and sediment dwellers that feed on organic material that slowly sinks from the light-filled surface regions. However, this picture has begun to change as a result of the latest scientific studies.
During an expedition in the Pacific Ocean, an international team of researchers led by the Chinese Institute of Deep Sea Science and Engineering discovered previously unexplored, gigantic chemosynthetic communities. Unlike conventional habitats, these living ecosystems do not depend on sunlight for energy, but derive it from chemical reactions in the seabed (quasi: chemically powered communities).
Using the manned Chinese submersible Fendouzhe, the scientists encountered an ecosystem that stretches over a length of 2,500 kilometers and reaches a depth of 9,533 meters. The images sent to the surface by the submersible from the bottom of the Kuril-Kamchatka Trench and the western Aleutian Trench are impressive.
The region studied is one of the deepest areas of the world's oceans. The result is a significant milestone in deep-sea research.
Scientific revolution in hadal research
The expedition with the high-pressure submersible “Fendouzhe” revealed that active and dense chemosynthetic communities exist in these gigantic depths, which reach up to 9533 meters, south and northeast of the Pacific Ocean. The area known as “The Deepest” is now considered the deepest known location where such communities have been found. It is teeming with dense colonies of tube worms, known as siboglinids, which live in the black sediment and extend their tentacles into the energy-rich hydrogen sulfide and methane-containing fluids that they produce themselves.
Researchers have discovered that these habitats are driven by geological processes that release methane from sediments. The methane is produced by the microbial decomposition of organic matter that has accumulated in the sediments and rises to the seabed through large faults and fracture zones. These fractures – known as cold seeps – are geologically active sites where methane, hydrogen sulfide, and other energy-rich substances escape from the Earth's interior and form the basis for the survival of chemosynthetic communities.
Formation and significance of cold seeps
Geological findings show that the sources of methane in these regions are primarily biogenic. The organic material deposited in the seabed through sedimentation is converted into methane by microorganisms under anaerobic conditions. This methane collects under the sediment layers and rises along large faults and normal fracture zones. There it escapes at the sea floor and provides the energy source for chemolithoautotrophic (chemically powered plant-like organisms) organisms.
These areas, known as cold seeps, are not an exception but could occur worldwide in all deep-sea trenches. Their discovery shows that the deep-sea habitat is much more diverse and active than previously thought. The communities consist of thousands of organisms per square meter, including mussels, tube worms, various benthic invertebrates (bottom-dwelling marine invertebrates), and microorganisms that live in symbiosis or are chemosynthetic.
Biological diversity and adaptations
The diversity of species that exist in these extreme environments is particularly exciting. Numerous new species have been discovered in the deep-sea areas studied, which have adapted to the high pressure and low oxygen conditions. While chemosynthetic communities usually only occur along selected sites in the shallower regions of the oceans, deep-sea expeditions show that such complex ecosystems can be interconnected over hundreds of kilometers.
Even in the most extreme depths, down to 9,533 meters, dense populations of tube worms, mussels, and other organisms can be found. This is because methane and hydrogen sulfide sources provide a continuous supply of energy, creating stable habitats that are dependent on sunlight.
This discovery shows that the deep sea is not just a storage room for organic particles, but an active habitat full of complex, chemically driven ecosystems. It revolutionizes our understanding of the limits of life on Earth and raises new questions—both for ecology and for the global carbon balance.
Solid evidence of the existence of these communities in the depths of the Pacific means that chemosynthetic ecosystems at the deepest points of the world's oceans are much more significant than previously thought and could play an important role in the global carbon cycle in the long term.
Discovered communities are no exception
Scientists believe that such systems are not an exception. Due to geological similarities, numerous other deep-sea trenches among the more than 20 known worldwide could harbor similar methane-based habitats.
The expedition thus provides definitive proof that large amounts of life do indeed exist in the most remote and deepest corners of the Earth. It confirms scientific theories that had previously only been suspected but never conclusively proven.
Danger from deep-sea mining
The study comes amid debate over the potential mining of raw materials on the seabed. Mining companies have long been pushing to extract valuable minerals from the ocean floor. However, scientists and environmental groups fear that deep-sea mining could permanently destroy pristine underwater ecosystems.
Credit and Link to the original study:
Peng, X., Du, M., Gebruk, A. et al. Flourishing chemosynthetic life at the greatest depths of hadal trenches. Nature (2025). https://doi.org/10.1038/s41586-025-09317-z