Yellow-band disease
Bacterial infection causing yellow lesions and coral death in the Caribbean.
Yellow-band disease, also known as Yellow Blotch disease, is a bacterial infection that targets coral colonies already weakened by pollution, overfishing, and climate change. The disease appears as large, bleached patches of yellowed tissue on Caribbean scleractinia corals. These pale-yellow or white lesions spread across the coral’s surface, marking areas where bacteria have destroyed the coral’s symbiotic algae, zooxanthellae. Since zooxanthellae provide the coral with essential energy through photosynthesis, their loss starves the coral, typically leading to death.
The coral’s relationship with zooxanthellae normally supplies it with glucose, glycerol, and amino acids. But when water conditions fluctuate—such as with changing temperatures or increased nitrogenous waste—the coral becomes stressed. These conditions also allow bacteria to grow inside the coral, competing with the zooxanthellae. The bacteria produce the characteristic pale-yellow lesions and eventually kill the algae by disrupting its ability to divide and perform photosynthesis. Yellow-band disease is found on Caribbean coral reefs.
The disease has severely impacted reef-building corals in the Caribbean. It has been linked to lower coral fecundity, changes in tissue composition, and reduced activity of certain enzymes. Compared to the late 1990s, current data suggest the disease remains a severe epidemic. In one study, 10-meter belt transects at various depths in the Lesser Antilles found that at 5 meters deep, 79% of coral colonies per transect showed yellow band rings and lesions, while only 21% appeared healthy. Recent research indicates the disease is still in an infectious phase in the Caribbean and has also been found to infect Pacific coral.
- Affected region
- Caribbean
- Depth with high infection
- 5 m
- Infection rate at 5m
- 79% of colonies per transect
- Healthy colonies at 5m
- 21%
- Associated impacts
- lower coral fecundity, altered tissue composition, lower activities of antixenobiotic and antioxidant enzymes
Lore & Background
Yellow-band disease is a bacterial infection that produces characteristic pale yellow lesions on coral by impairing the mitosis and photosynthesis of zooxanthellae, the coral's symbiotic algae. The disease thrives under water conditions such as fluctuating temperatures and increased nitrogenous waste, which stress the coral and allow bacteria to compete with zooxanthellae. Evidence suggests climate change could be worsening the disease.
The disease has severely affected reef-building corals in the Caribbean. In one study using 10-meter belt transects at various depths in the Lesser Antilles, at a depth of 5 meters, yellow band rings and lesions were found on 79% of colonies per transect, with only 21% appearing healthy. Current data indicates the disease remains a severe epidemic compared to the late 1990s.
Recent research indicates that yellow-band disease continues to be in an infectious phase in the Caribbean and has also been found to cause infection in Pacific coral.
Reader's Guide
Yellow-band disease is notable for its severe impact on reef-building corals in the Caribbean, where it has been associated with lower coral fecundity, altered tissue composition, and reduced activities of antixenobiotic and antioxidant enzymes. The disease remains a severe epidemic, as indicated by studies in the Lesser Antilles where at a depth of 5 meters, 79% of coral colonies per transect showed signs of infection. The disease's mechanism involves bacteria that impair the coral's symbiotic algae, leading to starvation and death. Climate change is suspected to worsen the disease, and recent research shows it has spread to Pacific coral, expanding its geographic reach. The disease's persistence and ability to infect multiple coral species underscore its significance as a continuing threat to coral reef ecosystems.
Did You Know?
- Yellow-band disease is similar to Yellow Blotch disease.
- The disease causes lesions where bacteria kill the coral's symbiotic algae, zooxanthellae.
- At a depth of 5 meters in the Lesser Antilles, 79% of coral colonies per transect had yellow band rings or lesions.
- Recent research indicates yellow-band disease has been found to cause infection in Pacific coral as well.
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