Underwater ecosystems are diverse environments found beneath the surface of oceans, rivers, and lakes. They include habitats like coral reefs, kelp forests, and freshwater wetlands, each supporting a variety of plant and animal life. These ecosystems play a crucial role in maintaining biodiversity and providing resources such as food and oxygen. Coral reefs, often referred to as the "rainforests of the sea," are particularly rich in species, including fish, mollusks, and sea turtles. Kelp forests provide shelter and food for marine life, while freshwater ecosystems support species like frogs and fish. Protecting these ecosystems is vital for environmental health and human well-being.