Subterranean ecosystems are environments located beneath the Earth's surface, including caves, underground rivers, and soil layers. These ecosystems host a variety of organisms, such as bacteria, fungi, and specialized animals like blind cave fish and troglobites, which have adapted to life in darkness and often rely on unique food sources. These ecosystems play a crucial role in nutrient cycling and water filtration. They help maintain soil health and support surface ecosystems by regulating groundwater and providing habitats for diverse species. Understanding subterranean ecosystems is essential for conservation efforts and maintaining biodiversity.