Information related to the health, chemistry, and conservation of marine ecosystems,  including coral reef health. 

marine-environment

Marine Environment

Data covering the marine environment, including fisheries, coral reef  health, ocean chemistry, and coastal zones.

oceans-seas-coasts

Oceans, Seas, & Coasts

### Overview  
  
The dataset shows up-to-date status, trends, and alerts related to sea surface temperature anomalies, which have the potential to cause bleaching where coral are present. Sea surface temperature (SST) is the water temperature close to the ocean's surface. The U.S. National Oceanic and Atmospheric Administration (NOAA) Coral Reef Watch (CRW) program has developed a daily global 5 kilometer (km) product suite based on satellite observations to monitor SST and thermal stress on coral reefs.

  
  
Mass coral bleaching events due to anomalously warm ocean water have increased in frequency and severity and have become one of the most significant contributors to the deterioration of the world’s coral reefs. Thermal stress that persists for several weeks with ambient water temperatures as little as 1 to 2 degrees Celsius (°C) above a coral’s thermal tolerance level has been shown to cause bleaching, often on broad geographical scales. Corals can die if thermal stress is severe or long-lasting; furthermore, coral weakened by thermal stress may subsequently succumb to disease. Extensive bleaching events have dramatic long-term ecological and social impacts, including loss of reef-building corals, changes in benthic habitat, reductions in fish productivity, and economic loss. Corals are capable of rebounding from bleaching, but not if the heat stress events are too severe or recur too quickly to permit recovery. As the climate continues to warm, bleaching is a major threat to the future of coral reefs.

  
  
Coral reefs are among the most biologically rich and productive ecosystems on earth and provide valuable ecosystem benefits to millions of people in coastal areas. They are, however, widely threatened by both local threats (such as overfishing, pollution, and direct physical damage) and the global threats of ocean warming and acidification. These have already caused widespread damage to most of the world’s coral reefs, resulting in reduced areas of living coral, increased algal cover, diminished species diversity, and lower fish abundance, as well as degraded economic and social benefits to many coastal communities.

  
  
Reliable global monitoring and prediction of environmental conditions leading to bleaching is used to guide targeted observations and management responses. The NOAA CRW products fulfill requests from coral reef managers and researchers for higher resolution products by taking advantage of new satellites, sensors and algorithms.
  
  
### Methodology  
  
The Coral Bleaching Monitoring dataset draws its layers from Version 3.1 of NOAA Coral Reef Watch’s experimental [coral bleaching heat stress monitoring product suite](https://coralreefwatch.noaa.gov/satellite/index.php). This product suite spans January 1, 1985 to present and is derived from CRW's Version 3.1 daily global 5 km satellite sea surface temperature (SST) data product known as ['CoralTemp'](https://coralreefwatch.noaa.gov/product/5km/index_5km_sst.php).

  
  
The Version 3.1 product suite was developed based on user requests and in order to address errors that were identified in the source SST data for CRW's Version 3.0 products for some coral reef regions during 2013-2016. It now comprises the core of CRW's Decision Support System (DSS) for coral reef management, providing service at or near reef-scales, allowing direct monitoring of 95% of global coral reefs and significantly reducing data gaps caused by cloud cover.

  
  
Note that SST variability is often considerably higher at the much finer 5 km spatial and daily temporal resolutions, when compared with CRW's heritage twice-weekly global 50 km (0.5 degree) monitoring products. Due to resulting day-to-day fluctuations between stress levels in highly variable locations, the single-day 5 km Bleaching Alert Area product does not consistently and adequately identify potentially harmful heat stress levels, especially with regard to accumulated heat stress impacts. Rather than requiring users to examine the single-day 5 km Bleaching Alert Area product over several days, a 7-day maximum Bleaching Alert Area composite product, updated daily, was introduced in the Version 2 product suite and is maintained here in Version 3.1. The evolution of CRW's daily global 5 km product suites can be found [here](https://coralreefwatch.noaa.gov/product/5km/history_5km_products.php). This 7-day composite product shows the maximum stress level that a satellite pixel has experienced during the most recent seven consecutive days. Data and images are dated on the last day of the 7-day period. Notably, it is compatible with CRW's heritage twice-weekly global 50 km Bleaching Alert Area product, as the 50 km Bleaching Alert Area is based on a half-week (3 or 4 days) composite of 50 km SSTs (but with much less SST variability due to its much coarser spatial resolution).

  
  
For the full documentation, please click on the “Learn more” button.
  
  
### Additional Information  
  
Resource Watch shows only a subset of the dataset. Additional data about heat stress frequency, heat stress onset, SST variability, SST trends, climatology, and annual SST history are available from the data provider. For access to the full dataset and additional information, click on the “Learn more” button.

  
  
CRW's first-generation (heritage) near real-time [twice-weekly global 50 km satellite coral bleaching heat stress monitoring products](https://coralreefwatch.noaa.gov/product/50km/) were operational at NOAA until April 30, 2020, when they were officially retired, and succeeded by CRW's next-generation operational daily global 5 km coral bleaching heat stress monitoring products. The heritage 50 km products served the U.S. and international coral reef communities for more than 20 years (1997-2020). While the 50km products no longer update in near real-time, due to their retirement, since they served as vital tools for our users for so many years, [archived 50km data and images](https://coralreefwatch.noaa.gov/product/50km/) are still available on the CRW website.
  
  
### Visualizing the Data  
  
Our team reformatted this dataset before displaying it on Resource Watch. See the documentation on how Resource Watch processed the data on [Github](https://github.com/resource-watch/nrt-scripts/tree/master/ocn_007_coral_bleaching_monitoring).  
  
### Disclaimer  
  
Excerpts of this description page were taken from the source metadata.

Ocean Watch

Coral Bleaching Monitoring

Past Week (as of July 15, 2024) Sea Surface Temperature Trend (°C/week)

Past Week (as of July 15, 2024) Bleaching Alert Area (7-Day Maximum)

July 15, 2024 Sea Surface Temperature (°C)

Past 12 Weeks (as of July 15, 2024) Degree Heating Weeks (DHW)

July 15, 2024 Sea Surface Temperature Anomalies (°C)

July 15, 2024 HotSpots (°C)