Plankton

Plankton are microscopic, free-floating aquatic organisms that are essential to food webs in both the ocean and freshwater habitats. They capture energy from the sun, drive biogeochemical cycles, and are a food source for many fish and other organisms. Plankton also play a role in global climate change as they absorb carbon dioxide, which is released into the atmosphere when they die. As such, they are an important component of the planet's carbon cycle. Plankton are especially important to the health of coral reefs, as they form the basis of the food chain in this fragile ecosystem.