Life can be pretty difficult in the ocean’s hydrothermal vents. It’s pitch black, oxygen is pretty scarce, and it’s full of magma.
In the hottest part of the Pacific’s hydrothermal vents, one invertebrate’s survival comes down to using the toxins spewing from these vents to their advantage. The deep sea worm Paralvinella hessleri reworks the toxin into a less hazardous and colorful material that it uses for protection. These findings are detailed in a study published August 26 in the journal PLOS Biology.
Meet Paralvinella hassleri
P. hessleri is a deep sea worm that lives in the western Pacific Ocean. These tiny invertebrates are only about five to 22 millimeters long and are primarily found in the Mariana Back-Arc basin east of the Philippines, towards the Okinawa Trough in the East China Sea. The hydrothermal vents P. hessleri calls home form when seawater meets magma within the Earth, producing oceanic hot springs and toxic gasses over 8,000-feet-deep.
The fluids that bubble up from underneath the Earth here contain high levels of the chemical compound sulfide and the element arsenic. The arsenic sometimes builds up in P. hessleri’s body tissue so much that it can make up more than one percent of the worm’s body weight.
“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,” study co-author Hao Wang said in a statement. “It was hard to believe that any animal could survive, let alone thrive, in such an extreme and toxic environment.”
Just how P. hessleri manages to survive and thrive in such a toxic environment has been a bit of a mystery. However, its bright yellow hue proved to be an important clue.
What do Rembrant and a deep sea worm have in common?
In the new study, a team from the Chinese Academy of Science’s Institute of Oceanology investigated how P. hessleri can tolerate such high levels of arsenic and sulfide. To better understand the worms’ detoxification process they put samples of P. hessleri under advanced microscopes and analyzed its DNA and the proteins and chemicals present in its body.
P. hessleri accumulates particles of arsenic in its skin cells. The accumulated arsenic then reacts with the sulfide coming up from the hydrothermal vent fluids. The results are small clumps of a toxic yellow mineral dating back to ancient Egypt and Mesopotamia and used by painters centuries ago called orpiment.
Seventeenth century Dutch painter Rembrandt van Rijn (aka Rembrandt) likely used the toxic orpiment to give his painting The Night Watch a unique golden hue. Venetian Renaissance artists Paolo Veronese, Tintoretto, and Giorgione also used the arsenic pigments in their work. However, it was not generated from sea worms. Instead, volcanic rocks are the most likely source.
P. hessleri’s orpiment is less toxic than what is coming out of the hydrothermal vent. According to the team, finding orpiment so far and away from the painter’s palette only adds to the discovery’s excitement.
“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,” said Wang. “It’s a curious convergence of biology and art history, unfolding in the depths of the ocean.”
[ Related: Newly discovered deep-sea worm moves like a ‘living magic carpet’ ]
Poison fights back
P. hessleri is essentially using the orpiment created from the vent’s toxins for “fighting poison with poison.” This adaptation and fighting style allows it to live in such a toxic environment by surrounding itself with a less toxic form than what’s coming out of the vents.
Other related worm species living in other parts of the world (and some snail species in the west Pacific) also accumulate high levels of arsenic. According to the team, it is possible that they deploy this same strategy.
While they may live in one of Earth’s most inhospitable zones, P. hessleri has certainly risen to the evolutionary challenge.
More deals, reviews, and buying guides