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Why Are Some Coral Reefs Dying? NOAA Satellites & NOAA’s Coral Program Help Conserve These Vulnerable Habitats

December 7, 2017

The ocean is home to critical coral reef ecosystems that provide a home to millions of plant, fish and marine animal species. Coral reefs are often called the “rainforests of the sea”. They are some of the most biodiverse and productive ecosystems on Earth. They account for just 0.1% of the ocean, but are home to a quarter of all marine species. Around the globe, some of the corals which provide the base of these fragile habitats are dying. When water temperatures rise above normal levels for too long, corals expel algae that live in their tissue and their white skeleton is exposed. This bleaching process leaves coral vulnerable and stressed which can result in death. The reefs are also threatened by human activities including pollution, unsustainable fishing practices, and global climate change.

Image of fish in the ocean
A NOAA Coral Reef Ecosystem Program diver attempts to record audio and visual data on a rare aggregation of the Green Bumphead Parrotfish (Bolbometapon muricatum) at Wake Atoll in the Pacific Remote Islands Marine National Monument. Credit: NOAA

We can still protect and preserve the remaining reefs, and NOAA is leading U.S. efforts to study and conserve these precious resources for future generations. How does NOAA’s fleet of satellites take part in this effort?

NOAA Satellites Monitor Sea Surface Temperature

Satellites provide a critical component of sea temperature monitoring. This data can help long and short-term marine ecosystem conservation efforts by alerting scientists and researchers to the potential for coral bleaching events.

NOAA’s satellites are able to quickly and efficiently capture ocean temperatures around the globe. Satellite remote sensing provides a near real-time global view of the oceans and monitor previously inaccessible remote reefs.

Satellites capture temperature data by detecting infrared and microwave wavelengths of energy emitting from the ocean. The variation in amplitude of these wavelengths is an accurate indicator of ocean temperature. NOAA’s GOES-16 satellite uses its Advanced Baseline Imager(ABI) and NOAA-20 will use its Visible Infrared Imaging Radiometer Suite (VIIRS) technology to collect this data.

The data enables scientists and forecasters to monitor and predict weather patterns with greater accuracy and to study long-term climate trends. Check out this near real-time data available HERE.

Satellite imagery of sea surface temperature anomalies, October 2017.
Satellite imagery of sea surface temperature anomalies, October 2017.

The Coral Reef Watch effort uses a blend of NOAA’s geostationary and polar orbiting satellite data to analyze sea surface temperature. This provides a 100-fold improvement in spatial resolution over earlier products. The new blended sea surface temperature products also help to reduce missing data caused by cloud coverage over the oceans. This is particularly vital in areas such as the “Coral Triangle,” which consists of the tropical marine waters of Indonesia, Malaysia, Papua New Guinea, Philippines, Solomon Islands and Timor-Leste that have months of persistent cloud cover some years.

Coral Reef Watch is supported by NOAA’s Coral Reef Conservation Program. The program delivers sound scientific information and tools that decision-makers and communities need to effectively address the primary threats facing coral reef ecosystems.

What Can You Do To Help?

Graphic image of coral reefs


  • Everyone can help protect coral reefs, here’s how!
  • Don't buy corals or give them as presents.
  • Conserve water. The less water you use, the less runoff and wastewater that will eventually find its way back into the ocean.
  • Volunteer in local beach or reef cleanups. If you don't live near the coast, get involved in protecting your watershed.
  • Become an informed consumer and learn how your daily choices like water use, recycling, seafood, vacation spots, fertilizer use, and driving times can positively (or negatively) impact the health of coral reefs.

Visitors to coral reef and coastal areas have an especially important role in protecting these vulnerable areas. Hiring a local guide to support the economy, picking up any trash, never touching or harassing wildlife in reef areas and avoiding dropping your boat anchor or chain nearby a coral reef - are all helpful.

Finally, stay informed and spread the word! Educate yourself about why healthy coral reefs are valuable to the people, fish, plants, and animals that depend on them.