Stony coral tissue loss disease (SCTLD)

node · earth · Florida and the wider Caribbean

A disease of Caribbean reef-building corals first observed off Miami-Dade County, Florida, in 2014, which spreads as a front of tissue loss across a colony and, unusually, across a reef — moving between colonies at rates that let it cross a whole reef tract in months and the Caribbean in years. It affects more than twenty of the region's reef-building species, with the massive brain and star corals among the most susceptible, and mortality in susceptible species is often close to total. Its causative agent has not been definitively identified, which is why it is described by its lesion rather than its pathogen; bacterial involvement is indicated by the partial success of antibiotic paste applied to lesion margins, a treatment now used at scale on individual colonies. SCTLD matters to this Journey because it is a stressor bleaching does not explain. Its severity is not tracked by degree heating weeks, and a reef can be losing coral fast in a summer with no thermal anomaly at all.