Research Findings
Researchers at Woods Hole Oceanographic Institution (WHOI) and the University of the Virgin Islands discovered that microorganisms in seawater surrounding corals indicate coral disease. This finding has implications for global reef health monitoring.
Coral reefs are crucial for marine life and human livelihoods, but forecasting coral disease has been challenging, often relying on visual inspections post-disease establishment. The study, published in Cell Reports Sustainability, demonstrated that changes in the seawater microbiome near corals more clearly indicate disease presence than microbes within the coral tissue itself.
Study Methodology
The research team monitored brain coral colonies (Colpophyllia natans) over four years on reefs near St. John in the U.S. Virgin Islands. This period included time before, during, and after the onset of stony coral tissue loss disease (SCTLD). Between 2020 and 2024, scientists collected samples from both coral tissue and the immediate surrounding seawater for genetic sequencing of microbes.
Key Observations
Microbes within coral tissue showed variability even in healthy corals. In contrast, microbes in the surrounding seawater remained stable near healthy corals but exhibited significant changes when corals became diseased during the SCTLD outbreak. Jeanne Bloomberg, lead author, stated that seawater microbes appeared to react to substances released by diseased corals, with the strongest effect observed during the disease's peak.
Implications for Reef Management
Stony coral tissue loss disease (SCTLD) has caused severe losses across the Caribbean. The study's findings suggest that seawater microbiomes can be used to diagnose coral disease and other reef disturbances. Amy Apprill, WHOI associate scientist, noted that integrating this approach with automated sampling and rapid genetic detection could establish an early warning system, enabling managers to intervene before irreversible damage occurs.
Marilyn Brandt, research professor at the University of the Virgin Islands, emphasized that earlier detection tools based on this work could allow for faster and more strategic responses to protect remaining corals.
This research introduces new pathways for scalable, non-destructive reef monitoring, which is critical as coral reefs globally face increasing pressures from warming oceans, pollution, and diseases. The ability to forecast reef health is considered an important step in reef protection.