As a new deadly coral disease sweeps through the Florida Keys and Caribbean, researchers are discovering how the disease is rapidly spreading with the catalyst being ballast water from large ships.
To identify and discover specifics of how this is occurring, researchers are working through shipping records which is housed at the Smithsonian to confirm and detail a way to slow the spread down and ultimately, stop it.
Stony coral disease was first discovered in Fall of 2014 in insolated sites with significant coral loss near Virginia Key, which is just southeast of Miami. Since 2014, the disease has rapidly spread through the keys and into parts of the Caribbean, wiping out systems of coral that are vital to the ecosystem.
While disease outbreaks are uncommon, what makes this specific one problematic and concerning is due its large geographic range, extended duration, rapid progression, high rates of mortality and the number of species impacted.
The disease is thought to be caused by bacteria and can be transmitted to other corals through direct contact and water circulation. Researchers are now currently working to identify potential pathogens and relationships with environmental factors, strategies to treat diseased colonies, and identify genotypes of corals that are resistant to the disease.
“This thing has now blown through most of the coral reef tract here in Florida,” said Dana Wusinich-Mendez, the Caribbean reef restoration team leader for the National Oceanic and Atmospheric Administration. “In 2014, we had no idea what it was when it came and what it was going to become. This has completely just overtopped [our] resources.”
The disease has spread over 300-miles of reefs and it is estimated that 90 percent of its coral cover.
The key to discovering that ballast may be the problem is when the disease started spreading to the Caribbean, defying ocean currents.They got their first solid clue in the U.S. Virgin Islands, Wusinish-Mendez said.
“Two weeks before the disease appeared in St. Thomas in the U.S. Virgin Islands, a ship there made an unauthorized release of ballast,” she said.
The ship had collected water from Port Everglades, where the disease spread after first appearing off Virginia Key near PortMiami in 2014.
“We watched when lionfish spread throughout the region, for example. We watched it follow the ocean currents and go from country to country across the region. This is jumping,” she said.
Ballast water is held in the ballast tanks and cargo holds of ships to provide stability and maneuverability during a voyage when ships are not carrying cargo, not carrying enough cargo, or when more stability is required due to rough seas. Typically, ballast water is pumped in tanks when a ships has delivered cargo to a port is departing with less cargo. Ballast water is often then transported and release at the nexst port-of-call where the ship will be picking up more cargo.
In the long term , all ships by 2024 will be required to have onboard treatment systems to clean water under a 2004 treaty adminsitered by the Internation Maritime Organization.
But in the mean time, investigators are now going over old records to see if they can confirm the movement of the disease with the movement of ships. By identifying this, they can help push ships to ensure they dump their ballast water just off shore in deep water and refill to avoid dumping on reefs.