Nannoplankton

Nannoplankton are tiny, floating microorganisms called plankton, specifically a type known as microplankton, that drift in the ocean. They are usually a few micrometers to a few complex micrometers in size and include both photosynthetic species, like coccolithophores, which produce calcium carbonate plates, and heterotrophic species that consume organic matter. Nannoplankton play a vital role in the Earth's climate by producing a significant portion of the world's oxygen and acting as a key part of the marine food chain. Their remains also help scientists study past climate changes through the fossils found in deep-sea sediments.