The Bio Argo floats, are used to measure large-scale changes in the chemistry and biology of marine ecosystems below the Indian Ocean's surface. The Argo floats are a network of 3600 free-floating sensors, operating in open ocean areas that provide real-time data on ocean temperature and salinity. They include additional sensors for dissolved oxygen, nitrate, chlorophyll, dissolved organic matter, and particle scattering. They will target specific gaps in the understanding of Indian Ocean ecosystems of immediate concern to India and Australia, such as the Bay of Bengal and the waters of north Western Australia.