Glimmers of Hope

A collaborative effort is helping the Florida Reef Tract cope with a coral disease outbreak.

The Coral Restoration Foundation helps to encourage reef health and diversity with their outplanting of boulder corals at Carysfort Reef.

Stony coral tissue loss disease first hit reefs surrounding Virginia Key near Miami, Florida, in the late summer of 2014, resulting in a rapid and extensive loss of important reef-building corals. This aggressive disease spread from reef to reef, progressing south into the Florida Keys by summer 2016, reaching the northern extent of the Florida Reef Tract off Martin County by spring 2017 and extending into the Lower Keys by spring 2018.

Shortly after the disease's discovery, scientists and managers began researching how to control it, but options have been limited. Stony coral tissue loss disease is vastly different from other coral diseases, which typically occur within a discrete area or among a few reefs and tend to last only a few months to a year, disappearing when the water cools. Stony coral tissue loss disease, however, affects more than 20 coral species, with with most of the colonies of these species on each reef succumbing to the disease within months of its initial appearance. The disease continues to spread with minimal decline in virulence.

Pinpointing the cause of this disease has been equally challenging. Previous coral disease outbreaks often followed coral bleaching events, as occurred in 2005 in the eastern Caribbean. Temperature stress can lower corals' resistance to disease. If the 2014 Florida-wide bleaching event was linked to the occurrence of this disease outbreak, however, it likely would have been much more widespread when it first appeared.

The first corals to show signs of stony coral tissue loss disease were among the most chronically stressed due to their proximity to Miami, where land-based sources of nutrients, sediment, contaminants and toxins are higher than elsewhere in the state. Coastal construction and dredging projects may have further exacerbated the situation.

The disease is transmissible among hosts and can be stopped using antibiotics, so it is presumed to be a bacterial pathogen spread via water movement. The exact cause and its source remain unknown, but ongoing research is getting closer to an answer.

A multidisciplinary team of experts from the National Oceanic and Atmospheric Administration (NOAA), the state of Florida and more than 40 other federal, state, academic, nonprofit and institutional partners is carrying out a multifaceted response to control or eliminate the disease. Along with coordinating restoration, they are studying the disease's epidemiology, potential causes and the role of other stressors and enabling factors. Through laboratory trials and extensive field testing, they developed localized treatments using a broad-spectrum antibiotic or chlorine and continue to refine treatment efforts.

The recent death of this brain coral (foreground) indicates the coral next to it will likely suffer the same fate from stony coral tissue loss disease.

Stony coral tissue loss disease affects corals differently depending on the species. Elliptical star coral (Dichocoenia stokesii), pillar coral (Dendrogyra cylindrus), maze coral (Meandrina meandrites) and flower coral (Eusmilia fastigiata) are the first species to be infected and the first to die. Brain corals are hit next, followed by boulder corals.

The simplest and fastest treatment, which is most effective on small lesions and corals with an early stage of the disease, is directly applying an antibiotic paste onto the diseased tissue. Researchers have successfully treated mountainous star coral by applying chlorine powder mixed into underwater epoxy along the disease margin. In later stages and for rapidly advancing lesions, they treat colonies much like containing a wildfire: by creating a firebreak. Using an angle grinder, they make a linear trench about 2 to 3 inches ahead of the diseased tissue and fill it with chlorinated epoxy or antibiotic paste. The disease burns out after it advances to the firebreak because no more living coral tissue is available to fuel the pathogen.

Field teams in southern Florida and the Florida Keys are targeting specific corals and reefs. A portion of the effort is directed toward the largest and most valuable framework corals (boulder corals) on iconic reefs, such as the sanctuary preservation areas in the outer reef tract of Florida Keys National Marine Sanctuary. Ongoing tests will determine if it is feasible to treat all corals within a single small reef located at the disease boundary and if that will change the trajectory of disease on a particular reef, saving the susceptible corals and reducing the spread to adjacent areas.

Science divers monitor the progression of stony coral tissue loss disease in
Florida Keys National Marine Sanctuary.
While research teams are treating corals on diseased reefs, another team is collecting representative colonies of the susceptible species from reefs that have not yet been exposed to the disease. They collected the first 200 corals in September and October 2018 to evaluate storage needs and develop genetic markers to determine the identity of each coral. Researchers transfer the rescued corals to aquaria throughout Florida for long-term preservation. Concurrently, scientists will propagate these corals using sexually produced offspring and through fragmentation for eventual return to the reef once it is deemed safe.

As outplanting onto the reef increases and the number of coral species successfully propagates, it is important to consider the risks. Few corals may survive the outplanting if they are moved to locations afflicted by disease outbreaks, while planting these corals at a site previously affected by an outbreak of stony coral tissue loss disease could reinvigorate the disease and increase its spread to neighboring, unaffected reefs.

Through an unprecedented collaborative effort, a dedicated response to stony coral tissue loss disease is underway within the Florida Reef Tract. By advancing understanding of the disease and developing options to manage it, the project offers glimmers of hope for a threatened coral reef ecosystem.

Andrew Bruckner is research coordinator for the Florida Keys National Marine Sanctuary.

How Divers Can Help
By Gena Parsons

Divers should stay informed about where stony coral tissue loss disease is present, use proper diving techniques and decontaminate dive gear between dives as well as before and after each dive excursion, especially when traveling from infected to uninfected locations or to and from other countries.

Decontaminating Dive Gear
After a dive, immediately rinse your gear to remove debris and sediment. Use a bleach solution to sanitize nonsensitive gear that might get close to corals. Wash other gear in fresh water with an antibacterial soap. Use quaternary ammonium solutions to decontaminate dive gear after returning to shore. For the internal bladder of your buoyancy compensator (BC), pour approximately 1 pint (0.5 liters) of disinfecting solution into the mouthpiece of the BC's exhaust hose while depressing the exhaust button, fully inflate the BC, and gently rotate it in all directions. Let it sit for 10 minutes, and then flush twice with fresh water.

Regulators, computers, gauges and other sensitive equipment should soak for 20 minutes in a solution of warm water and antibacterial dish soap or OdoBan disinfectant. Rinse in fresh water, and air dry. Thoroughly rinse underwater camera housings with fresh water, and press the buttons or levers to ensure no particulates become lodged. You can also thoroughly wipe sensitive gear with isopropyl alcohol.

It is important to properly dispose of disinfectant solutions and rinse water in a sink, tub or shower. Never pour these liquids into the ocean or a storm drain.

Reporting Coral Conditions
Divers can report coral conditions to the Southeast Florida Action Network (SEAFAN), the Florida Department of Environmental Protection's public reporting tool for protecting southeastern Florida's coral reefs. Reporting observations greatly enhances scientific knowledge of disease presence and helps to identify key areas for targeted research and interventions. The observations also help to identify particularly valuable and resilient reefs that may remain healthy. Training is available for those who wish to participate. For more information, visit

Restoring the Reef
Restoration of the most resilient species of corals will be key to the future of reefs in Florida and around the world. Nonprofit organizations such as Mote Marine Laboratory and the Coral Restoration Foundation use volunteer divers to assist with maintaining coral nurseries and outplanting corals on the reefs. As stony coral tissue loss disease wanes, either naturally or due to human intervention, restoration efforts will ramp up to new levels.

Relieving Stress
For restoration to be successful, we must relieve stress on the ecosystem — an effort that involves every resident of and visitor to Florida — by improving water quality, reducing runoff and keeping trash contained. Use reef-friendly sunscreen, and wear sun-protection clothing. Practice safe boating, and use mooring buoys to avoid anchor damage to corals. Opt for sustainable seafood to address overfishing.

Expanding Your Education
Coral reefs cover less than 1 percent of the Earth's surface but are home to 25 percent of all marine fish species at some point in their life cycle. Coral diseases are increasing in frequency, intensity and geographic range. NOAA and other sources provide a plethora of online information about corals. For more information about stony coral tissue loss disease and how you can help, visit the Florida Keys National Marine Sanctuary's website at

Dive Gear Decontamination Guidelines
  • Nonsensitive equipment — Soak for 10 minutes in a 10 percent bleach solution (1 quart of bleach in 2 gallons of water). Rinse with fresh water, and air dry.
  • Wetsuits, BCs, masks and fins — Soak for 10 minutes in one of the following: 0.5 percent RelyOn disinfectant cleaner (four 5-gram tablets in a gallon of water), 1 percent Virkon S disinfectant (1.3 ounces in 2 gallons of water), 6.6 percent Lysol disinfectant (1 quart in a gallon of water) or an equal concentration of another quaternary ammonium disinfectant. Soak in fresh water for 10 minutes, and air dry.
  • BC internal bladders — Pour 1 pint (0.5 liters) of disinfecting solution in the mouthpiece of the BC's exhaust hose while depressing the exhaust button. Fully inflate the BC, and gently rotate it. After 10 minutes, flush twice with fresh water.
  • Regulators, computers, gauges and other sensitive scientific equipment — Soak for 20 minutes in warm water with antibacterial dish soap or OdoBan disinfectant (5 ounces in a gallon of warm water). Rinse in fresh water, and air dry. Thoroughly wipe with isopropyl alcohol.
  • Underwater cameras — Thoroughly rinse with fresh water, and press buttons and levers to ensure no particulates become lodged. Thoroughly wipe the outside of the housing with isopropyl alcohol.

This protocol does not endorse, recommend or favor any specific commercial product, process or service and is provided only to inform the public. Safety data sheets for chemicals and manufacturers' user manuals provide critical information about the physical properties, reactivity, potential health hazards, storage, disposal and appropriate first-aid procedures for handling, applying and disposing of each product in a safe manner.

Gena Parsons is the communications and outreach manager at the Florida Keys National Marine Sanctuary.
Explore More
Learn more about Florida's coral disease outbreak and see an animated map of its progress at

Stephen Frink offers a contemporary and inspiring view of Key Largo reefs post stony coral disease in an online photo gallery.

Watch a video by Florida's Fish and Wildlife Research Institute showing diseased brain corals at Hen and Chickens Reef in the Florida Keys National Marine Sanctuary.

© Alert Diver — Q1 Winter 2019