Coral reefs are being threatened and satellites are expanding the virtual network to watch for increases in ocean temperatures that can damage or kill the fragile ecosystems of coral reefs worldwide. The National Oceanic and Atmospheric Administration (NOAA) uses onsite water instruments to monitor ocean temperatures at about a dozen reefs. The expanded system uses satellites to remotely monitor water temperature and other factors without the high cost of deploying devices. A 2° rise in typical summertime water temperature can stress corals, causing the tiny marine creatures that form reefs to expel algae living in their tissues. This bleaching process upsets the nature of the ecosystem by exposing their white skeletons. The expansion of this critical climate monitoring tool will help scientists better understand and mitigate the impacts of warming waters that contribute to the bleaching damage. Corals are needed because they serve as a breeding ground and habitat for many of the world's marine species and act as indicators of overall ocean health.