Scientists have found evidence of deep-sea organisms engineering their own environments in sediments from over 7.5 kilometers below the ocean surface. Researchers Jussi Hovikoski and colleagues analyzed sediment cores from the Japan Trench, a part of the deepest ocean called the Hadal Zone. The study, published in Nature Communications, shows that sediment is deposited by gravity flows and then colonized by organisms that exploit new nutrient-rich and oxygenated bottom sediment.
The findings suggest that early colonizers could be holothurians, or sea cucumbers, which break down organic matter and create a food source for other species. As the matter decomposes, the sediment becomes oxygen-starved, leading to the presence of invertebrate species that utilize microbial communities. This process is crucial for understanding the poorly understood ecosystem of the Hadal Zone.
The study provides valuable insights into bioturbation, which affects nutrient cycling and ecosystem functioning. By documenting these traces in deep-sea sediments, scientists can shed light on this previously unexplored environment.
Source: https://phys.org/news/2025-02-deep-sea-ocean-floor-km.html