A new study in the journal Nature confirms the presence of large sea animals in some of the deepest parts of the Pacific Ocean. Scientists from the Chinese and Russian Academies of Sciences explored the Kuril–Kamchatka and Aleutian trenches, located in the northwest Pacific Ocean. They used a special submersible vehicle to reach depths of over 31,000 feet (9.5 kilometers). In these places, researchers found tubeworms and mollusks living in very harsh conditions—where the water is extremely cold, the pressure is strong, and there is no sunlight. These areas were once thought to be nearly impossible for larger animals to survive. The results support earlier ideas that life can exist at such extreme depths.

Experts believe these deep-sea animals survive by using a process called chemosynthesis. Microbes living in the trenches change carbon into energy-rich chemicals. These chemicals are then used as food or shared with other animals in a close relationship. This way of living is different from what scientists expected. Marine biologist Julie Huber said that the types of animals found in these places were not known before because the area was so hard to explore. The discovery may help future studies of deep-sea life and could lead scientists to search for more unknown ocean ecosystems.