Microbial CDR antidote to methane climate "bombs" found in deep sea trenches
Tom Goreau
Microbial CDR antidote to methane climate "bombs" found in deep sea trenches
The astonishing discovery of rich ecosystems driven by methane oxidation 10 kilometers deep in the North Pacific by Chinese researchers shows there is a strong biological sink for deep methane hydrate releases.
While there is clear evidence of massive methane releases in various places, most of the methane seems to be consumed as food by eager microbes before it reaches the atmosphere.
For example after the Gulf of Mexico oils spill, vast amounts of methane were released into the water. Oceanographers raced to the Gulf of Mexico to measure methane and use it as a tracer for deep water circulation, but by the time they got there it had all been eaten and turned into CO2!
No surprise to me, I made some of the first measurements of methane consumption by soils:
M. Keller, T. J. Goreau, S. C. Wofsy, W. A. Kaplan, & M. B. McElroy, 1983, Production of nitrous oxide and consumption of methane by forest soils, GEOPHYSICAL RESEARCH LETTERS, 10: 1156-1159
- NATURE Article
- Open access
- Published: 30 July 2025
Flourishing chemosynthetic life at the greatest depths of hadal trenches
- Xiaotong Peng,
- Mengran Du,
- Andrey Gebruk,
- Shuangquan Liu,
- Zhaoming Gao,
- Ronnie N. Glud,
- Peng Zhou,
- Ruoheng Wang,
- Ashley A. Rowden,
- Gennady M. Kamenev,
- Anastassya S. Maiorova,
- Dominic Papineau,
- Shun Chen,
- Jinwei Gao,
- Helu Liu,
- Yuan He,
- Inna L. Alalykina,
- Igor Yu. Dolmatov,
- Hanyu Zhang,
- Xuegong Li,
- Marina V. Malyutina,
- Shamik Dasgupta,
- Anastasiia A. Saulenko,
- Vladimir A. Shilov,
- …
- Andrey V. Adrianov
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Nature (2025)Cite this article
Abstract
Hadal trenches, some of the Earth’s least explored and understood environments, have long been proposed to harbour chemosynthesis-based communities1,2. Despite increasing attention, actual documentation of such communities has been exceptionally rare3,4. Here we report the discovery of the deepest and the most extensive chemosynthesis-based communities known to exist on Earth during an expedition to the Kuril–Kamchatka Trench and the western Aleutian Trench using the manned submersible Fendouzhe. The communities dominated by siboglinid Polychaeta and Bivalvia span a distance of 2,500 km at depths from 5,800 m to 9,533 m. These communities are sustained by hydrogen sulfide-rich and methane-rich fluids that are transported along faults traversing deep sediment layers in trenches, where methane is produced microbially from deposited organic matter, as indicated by isotopic analysis. Given geological similarities with other hadal trenches, such chemosynthesis-based communities might be more widespread than previously anticipated. These findings challenge current models of life at extreme limits and carbon cycling in the deep ocean.
Scientists discover a whole new type of ecosystem 30,000 feet deep
In Pacific Ocean trenches, scientists found creatures that expand the limits of where we know life can live on Earth.
July 30, 2025 at 11:10 a.m. EDTYesterday at 11:10 a.m. EDT
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Researchers find life at extreme depths under the sea
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Scientists from the Chinese Academy of Sciences found life 9,500 meters undersea in trenches of the northwest Pacific Ocean. (Video: Institute of Deep-sea Science and Engineering, CAS (IDSSE, CAS))
When her three-person submersible descended more than 30,000 feet into one of the Pacific Ocean’s deepest trenches, Mengran Du wasn’t sure what they would find.
What she saw, she recalled, was “unbelievable”: Dense clusters of tubeworms with tentacles tinged bloodred, jutting up like skyscrapers. Iridescent snails scaling the worms, like window washers. Bristly, white creatures wriggling between them like rush-hour commuters trying to get home for dinner.
An international team of researchers has discovered the world’s deepest known ecosystem sustained by chemicals seeping from the seafloor, submerged in water and darkness. The discovery expands the limits of where we know life can live on Earth.
“It’s a unique ecosystem,” said Dominic Papineau, an exobiologist who co-wrote the study on the deep-sea discovery published Wednesday in the journal Nature. “It’s a totally new thing that has not been seen before.”
The bottom dwellers, found in the Kuril-Kamchatka and Aleutian trenches, between Russia and Alaska, “alter our understanding of trench ecosystems,” said Lisa Levin, a professor emeritus of biological oceanography at Scripps Institution of Oceanography, who was not involved in the study.
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For decades, scientists have studied organisms that thrive around hydrothermal vents, fissures spewing superheated fluids. But the creatures that live around cold seeps — places where gases such as methane and hydrogen sulfide ooze from the seafloor at near-freezing temperatures, often where tectonic plates meet — have been understudied.
So, to investigate, an expedition to the northwest Pacific last summer used the crewed submersible Fendouzhe to dive into the hadal zone, the ocean’s deepest region, named for Hades, the Greek god of the underworld.
China, the United States and others have been seeking to capitalize on the mineral wealth of the seafloor, mining metals for use in electric cars and other technology — and prompting concern about upending deep-sea life.
The trenches examined in the new study are probably too deep for mining. Their exploration demonstrates newly acquired abilities by countries and companies to investigate the open ocean.
“People know very little about the bottom of the trench,” said Du, a geochemist with China’s Institute of Deep-sea Science and Engineering, which led the study. For decades, she added, researchers lacked the “high technology to enable us to go there.”
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A crewed submersible with a high-definition camera found an ecosystem in the Kuril-Kamchatka and western Aleutian trenches. (Institute of Deep-sea Science and Engineering, CAS)
The researchers, once down there, found they weren’t alone. They discovered communities of animals dominated by marine tubeworms and mollusks spanning over 1,500 miles of total darkness.
Elsewhere on Earth, sunlight sustains life. Photosynthesis performed by plants or algae is the base of almost all food webs. Ocean scientists previously assumed trench creatures eked out an existence by feasting directly on dead animals and other organic matter that fell from sunlit parts of the ocean into the crevasses.
But in the hadal zone, life appears to sustain itself through a more meandering method.
Analysis of gases seeping from the seafloor suggests microbes are consuming organic matter that accumulates in the trenches and belching methane after their meals. Symbiotic bacteria inside the tubeworms and mollusks, in turn, absorb the methane and hydrogen sulfide from those cold seeps to produce organic matter to nourish their hosts.
The process, called chemosynthesis, may seem like an alien way for an animal to score dinner, but Papineau noted that humans have their own colonies of microbes that aid in digestion. “We ourselves have bacteria in our gut,” he said.
The researchers expect several of the specimens they plucked from the trenches will yield species new to science, though they don’t know how many. “This is the next paper,” Papineau said.
They also don’t know exactly how these animals survive the extraordinarily high pressures found in the trenches.
“They must have some trick, or they must have some unique metabolic pathway, to adapt to the high pressure,” Du said.
But the most surprising finding, according to biologist Lesley Blankenship-Williams, is about where all that nourishing methane is coming from: not from geological processes deep in the Earth, but from microbes in the sediment.
“Flourishing chemosynthetic communities had long been postulated to exist in the trenches, but this is the first paper that documents their existence below nine kilometers and at multiple locations,” said Blankenship-Williams, a professor at Palomar College in California who was not involved in the study.
The research team found life on 19 of 23 dives over a 40-day period, suggesting that hadal ecosystems may be common in Earth’s ocean trenches.
The extreme adaptability of organisms in those trenches gives hope to those searching for evidence of life in oceans on other worlds, such as Jupiter’s icy moon, Europa.
“There is about 3,700 million years of Earth evolution between the oldest animal fossils to the oldest microbial fossils,” Papineau said. “So, if deep extraterrestrial oceans existed for billions of years, then perhaps similar chemosynthetic-based ecosystems with animal-like creatures could also exist there.”
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The comments reflect a mix of fascination and concern about the newly discovered deep-sea ecosystem. Many express awe at the unique life forms and the potential insights they offer into the origins of life and possibilities of life on other planets. However, there is also... Show more
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Dino Grandoni is a reporter covering wildlife, biodiversity and other climate and environmental issues. He is the author of Animalia, a column exploring the strange and fascinating world of animals.follow on X@dino_grandoni