Coral disease outbreaks have emerged as a major cause of coral mortality and reef decline globally. They are often linked to declining water quality, overfishing and heat stress and are now on the rise in areas of the Great Barrier Reef.
AIMS first recorded evidence of coral disease on the Reef in the early 1990s, when we began regular surveys.
Our research currently estimates that disease accounts for at least six per cent of coral mortality. However, disease prevalence in some regions of the Reef is similar to that reported in the Caribbean, where reefs have suffered the loss of 80 per cent of their coral in the last 20 years.
With increasing pressures on the reef, including crown-of-thorns outbreaks, bleaching associated with heat stress, and declining water quality, the impact of disease is likely to increase and further exacerbate the decline of coral health.
The most common diseases observed on the Great Barrier Reef include white syndrome, black band and brown band disease. The lethal mechanisms of these diseases are not well understood at present.
AIMS researchers are studying marine microbes (tiny bacteria, viruses and protists) associated with diseased coral to find out whether they are the cause of the disease, a symptom of stressed corals or a cause of stress that weakens corals' defences, allowing infection.
Better understanding of the microbial pathogens and partnerships associated with corals is providing new insight into reef health.
By understanding the host, causative agents and environmental drivers that contribute to disease, we can provide critical information and tools to coral reef managers to prevent or mitigate large-scale disease outbreaks.
We can also provide researchers with early warning indicators of stress in marine ecosystems.