WEST PALM BEACH, Fla. (AP) — Satellites are helping scientists expand a 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 said Thursday its Coral Reef Watch network has been expanded from 24 to 190 locations, including sites in the Florida Keys, the Caribbean, Gulf of Mexico, the Indian and Pacific oceans, Indonesia, Australia and Hawaii.

The agency 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 mere 2-degree rise in typical summertime water temperature can stress corals, causing the tiny marine creatures that form reefs to expel algae living in their tissues. The so-called bleaching upsets the symbiotic nature of the ecosystem by exposing their white skeletons.

Many corals can recover from a mild, short-lived bleaching event. But if it occurs over a longer period, entire colonies die. The Caribbean region has lost at least 50 percent of its corals, largely because of warmer seas.

"Bleaching is a major threat to the health of endangered coral reef ecosystems across the earth," NOAA administrator and retired Navy Vice Adm. Conrad C. Lautenbacher said. "The expansion of this critical climate monitoring tool will help us better track, understand and mitigate the impacts of warming waters that contribute to the bleaching damage."

With advance warning, scientists hope environmental managers can limit non-climate related stresses to reefs, such as temporarily halting fishing in an area, limiting public access or stopping nearby construction projects that may be coating corals with sediment.

The more resilient and healthy corals are before a bleaching event, the better chance they'll have to survive and recover. It's the best scientists can do for now to protect reefs, which are suffering worldwide from overfishing, pollution, coastal development and climate change.

"We just need to build up a new body of knowledge and understanding about what works and what doesn't work," said Roger McManus, Conservation International's vice president for global marine programs. "Then we should be able to improve our management."

Corals serve as breeding grounds and habitat for many of the world's marine species and act as indicators of overall ocean health. A study published in the journal Science last year warned that if carbon emissions continue at today's rate, all corals could be extinct within 100 years.