Deepest Chilean cold seeps discovered: Insights into life without sunlight

An extraordinary discovery was made during an expedition to explore the Atacama Trench, a formation with a depth of around 8,000 meters stretching along Peru and Chile. According to IFL Science, scientists aboard the research vessel Schmidt Ocean Institute's R/V Falkor (too) identified the deepest and northernmost Chilean cold seeps. They also noticed something else that captured their attention.

The cold seeps were discovered at a depth of about 2,800 meters. These areas where hydrocarbons, such as methane, create bubbles on the ocean floor. Finding these record-breaking seeps took more than 12 hours and required seafloor mapping data. All evidence indicates that these are methane seeps, a phenomenon known from subduction zones, where two tectonic plates collide. Methane is valuable for deep-sea animals like clams, lobsters, and tube worms as it nourishes bacteria that are part of their diet.

"The microbes that live on these seeps have amazing strategies for producing food without sunlight," said Dr. Lauren Seyler of Stockton University in New Jersey. She added: "Here on Earth, life in the dark is alien in its own right and provides critical information for understanding how organisms persist under the most extreme conditions. We are still trying to figure out how life started on Earth, and environments that provide chemical energy for life, like this one, might offer clues about the spark that ignited all the biodiversity on our beautiful planet."

Dr Armando Azua-Bustos from the Centro de Astrobiología added that "the Atacama Desert is a well-known Mars analog model here on Earth. It contains precious insights for how life, if it ever arose on Mars, might be able to adapt to an increasingly drying plane." Scientists hope that the collected data will assist in the search for biosignatures on the moons Enceladus and Europa, which potentially could harbour traces of life.

During the expedition, 70 specimens were collected, some of which might be new species to science. Living fossils, such as brachiopods, leptochitons, and crinoids, considered close descendants of fossils found in the Atacama Desert, could also be present. Also observed on the ocean floor were "sea pigs"—bizarre deep-sea cucumbers that scavenge the ocean floor in search of organic material.

Sea cucumbers are invertebrates found in deep-sea areas worldwide. They usually reach lengths of 5 to 15 centimetres and live at depths ranging from about 550 to 6,700 metres. They spend their lives in muddy sediments on the seafloor, feeding on pieces of dead algae and animals. There are many species of sea cucumbers, and many are still undiscovered.

For instance, in March 2024, the crew of the research vessel James Cook discovered a new, unusual species of "sea pig." In the eastern Pacific region, in an area known as the Clarion-Clipperton Zone, they encountered a pink creature, which, due to its colour, was named "Barbie pig."