Deep in the Pacific Ocean, a tiny bright yellow worm called Paralvinella hessleri thrives where almost nothing else can, around boiling hydrothermal vents that gush metal-rich, poisonous fluids. These underwater chimneys are packed with toxic substances, including arsenic and hydrogen sulphide. Yet, instead of dying, the worm uses these poisons to its advantage. According to a study published in PLOS Biology, P. hessleri converts the toxins inside its body into orpiment, a golden mineral that neutralises the danger. This remarkable adaptation enables the worm to survive and even flourish in one of Earth’s harshest habitats.
How the yellow worm survives toxic hydrothermal vents
The Paralvinella hessleri worm lives thousands of metres below the ocean’s surface, clinging to the sides of hydrothermal vents. These vents release scorching fluids that can reach high temperatures and contain high levels of toxic metals and gases.Despite this, the worms form dense colonies right near the vent openings, closer to danger than most other sea creatures dare to live.They build thin, tube-like shelters that protect them from sudden bursts of hot fluid. Inside these tubes, the worms feed on bacteria and organic particles that grow in the mineral-rich water. To most animals, the vents would be instant death. To P. hessleri, they are home.
How a deep-sea worm turns deadly arsenic into a golden shield
What makes this worm truly special is how it deals with poison. The study found that up to 1% of the worm’s body weight is made of arsenic, a level that would be fatal to any other creature. But instead of dying, the worm stores the arsenic safely inside its skin cells.Inside those cells, the arsenic reacts with another poison, sulphide, to form tiny crystals of a mineral called orpiment. Orpiment is bright yellow and non-reactive, meaning it no longer harms the worm. In other words, P. hessleri neutralises one poison by mixing it with another. It literally “fights poison with poison.”This process also gives the worm its stunning golden-yellow colour, nature’s way of showing off a chemical shield.
The hidden process behind the worm that turns poison into gold
Scientists discovered that the worm forms small yellow granules inside its skin and gill cells. Under powerful microscopes, these granules were revealed to be made of arsenic and sulphur. The worm’s body moves arsenic into these cells using special transport proteins, while sulphide seeps in naturally from the vent water.Once both elements meet inside tiny storage bubbles within the cells, they crystallise into orpiment. This clever mineralisation process traps the toxins in solid form, keeping the worm safe from harm.
The worm that creates the golden pigment ‘King’s Yellow’
The golden mineral that the worm produces, orpiment, has a long history on land. Hundreds of years ago, artists used crushed orpiment as a paint pigment called “King’s Yellow” to create gold-like tones in paintings. It was beautiful but dangerous because it contained arsenic.Now, scientists have found that a deep-sea worm naturally produces the same mineral, not for beauty, but for survival. It’s an incredible example of how evolution reuses chemistry in unexpected ways.Also read | The ‘Wookiee of the deep sea’: Exploring habitat and features of Iridogorgia chewbacca, found 400–1,000 metres below
