In the deepest parts of the Pacific Ocean, a glowing yellow worm has mastered survival in one of the most toxic places on Earth.
Bathed in arsenic and sulfide from hydrothermal vents, it neutralizes the poisons by transforming them into golden mineral crystals, turning deadly chemicals into glittering protection.
Poison-Resistant Worm Discovery
A deep-sea worm that lives around hydrothermal vents has evolved a remarkable survival trick: it combines two deadly substances, arsenic and sulfide, inside its cells to create a far less harmful mineral. The discovery, described by Chaolun Li of the Institute of Oceanology, CAS, China, and his colleagues, was published August 26th in the open-access journal PLOS Biology.
The species, known as Paralvinella hessleri, is the only animal that can withstand the hottest zones of deep-sea vents in the western Pacific. These vents gush out superheated, mineral-rich water containing high concentrations of sulfide and arsenic. Over time, the arsenic accumulates in the worm’s tissues, in some cases accounting for more than 1% of its total body weight.
Life in Extreme Deep-Sea Vents
To uncover how P. hessleri survives such a hostile environment, Li’s team used advanced microscopy along with DNA, protein, and chemical analysis. Their work revealed an entirely new detoxification process. The worm traps arsenic particles in its skin cells, where they interact with sulfide from the vent fluids to form clusters of a bright yellow mineral called orpiment.
This unusual process sheds light on a strategy that researchers describe as “fighting poison with poison.” It allows the worm to live in an environment that should be lethally toxic. Other studies suggest that some closely related worm species and certain snails in the western Pacific also build up large amounts of arsenic and may rely on a similar adaptation.
Fighting Poison With Poison
Coauthor Dr. Hao Wang adds, “This was my first deep-sea expedition, and I was stunned by what I saw on the ROV monitor—the bright yellow Paralvinella hessleri worms were unlike anything I had ever seen, standing out vividly against the white biofilm and dark hydrothermal vent landscape. It was hard to believe that any animal could survive, let alone thrive, in such an extreme and toxic environment.”
Dr. Wang says, “What makes this finding even more fascinating is that orpiment—the same toxic, golden mineral produced by this worm—was once prized by medieval and Renaissance painters. It’s a curious convergence of biology and art history, unfolding in the depths of the ocean.”
A Strange Link to Art History
The authors note, “We were puzzled for a long time by the nature of the yellow intracellular granules, which had a vibrant color and nearly perfect spherical shape. It took us a combination of microscopy, spectroscopy, and Raman analysis to identify them as orpiment minerals—a surprising finding.”
The authors conclude, “We hope that this ‘fighting poison with poison’ model will encourage scientists to rethink how marine invertebrates interact with and possibly harness toxic elements in their environment.”
Reference: “A deep-sea hydrothermal vent worm detoxifies arsenic and sulfur by intracellular biomineralization of orpiment (As2S3)” by Hao Wang, Lei Cao, Huan Zhang, Zhaoshan Zhong, Li Zhou, Chao Lian, Xiaocheng Wang, Hao Chen, Minxiao Wang, Xin Zhang and Chaolun Li, 26 August 2025, PLOS Biology.
DOI: 10.1371/journal.pbio.3003291
Funding: This work was supported by grants from Natural Science Foundation of China (No. 42476133 to H.W.), Science and Technology Innovation Project of Laoshan Laboratory (Project Number No. LSKJ202203104 to H.W.), National Key RandD Program of China (Project Number 2018YFC0310702 to H.W.), Natural Science Foundation of China (Grant No. 42030407 to C.Li), and the NSFC Innovative Group Grant (No. 42221005 to M.X.W.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
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