Coral Bleaching is a phenomenon impacting coral reefs all over the world. Anthropgenic impacts such as rising sea surface temperatures, excess runoff and pollution, overexposure to sunlight, and extreme low tides are stressing coral reef ecosystems. Under stress, coral reefs can expel the photosynthetic algae living in their tissues called zooxanthellae. Coral and zooxanthellae have a mutualistic relationship; the zooxanthellae living in the protective environment of the coral, while the coral receives nutrients and its vibrant color from the algae.
Image courtesy of NOAA's Coral Reef Conservation Program
Without this photosynthetic algae, not only does the coral "bleach", but it is also losing its main food source, and is more susceptible to disease.
A strong El Nino event lasting into 2016 caused even higher than normal sea surface temperatures, increasing coral bleaching events in these areas. According to Mark Eakni, NOAA's Coral Reef Watch Coordinator, “The coral bleaching and disease, brought on by climate change and coupled with events like the current El Niño, are the largest and most pervasive threats to coral reefs around the world. As a result, we are losing huge areas of coral across the U.S., as well as internationally".
Coral bleaching doesn't always immediately kill off coral. However, coral reefs recovery is often slow, causing a loss in fish habitat, food sources, and tourism. Many of these coral reef systems have survived for hundreds of years leading scientists to believe that the current rise in temperatures is a key indicator of rising temperatures unlike any seen in their history.
Reef Life Restoration is helping to restore our coral reef's by placing an engineered reef adjacent to bleached and damaged reefs. The new reef can incubate coral spawn to enrich the oceanic community in that region, enhance tourism, grow more algae and other organisms for marine life. These artificial reefs systems can help with the recovery of our world's bleached and recovering reef ecosystems.