An emerging coral disease outbreak decimated Caribbean coral populations and reshaped reef functionality

Abstract

Diseases are major drivers of the deterioration of coral reefs, linked to major declines in coral abundance, reef functionality, and reef-related ecosystems services1-3. An outbreak of a new disease is currently rampaging through the populations of the remaining reef-building corals across the Caribbean region. The outbreak was first reported in Florida in 2014 and reached the northern Mesoamerican reef by summer 2018, where it spread across the ~ 450-km reef system only in a few months4. Rapid infection was generalized across all sites and mortality rates ranged from 94% to < 10% among the 21 afflicted coral species. This single event further modified the coral communities across the region by increasing the relative dominance of weedy corals and reducing reef functionality, both in terms of functional diversity and calcium carbonate production. This emergent disease is likely to become the most lethal disturbance ever recorded in the Caribbean, and it will likely result in the onset of a new functional regime where key reef-building and complex branching acroporids (a genus apparently unaffected) will once again become conspicuous structural features in reef systems with yet even lower levels of physical functionality.

Differences in the progression rate of SCTLD in Pseudodiploria strigosa are related to colony size and morphology

“…Differences in rates of tissue loss could be influenced by coral resilience, environmental stress, or differences in pathogen virulence (Meiling et al, 2020). Yet, indistinctly of the rates of tissue loss, the percentage of colonies that ended up dying due to the disease in our study is similar to previous reports in our study region (Guzmań-Urieta and Jordán-Dahlgren, 2021;Alvarez-Filip et al, 2022) and elsewhere in the Caribbean (Precht et al, 2016;Costa et al, 2021;Williams et al, 2021). This suggests that despite differences in the rate of tissue loss when the disease reaches a site, a high proportion of the population will eventually die.…”

“…For example, foliose and massive species can easily accumulate sediment and thus a greater load of pathogens (Jones et al, 2019). In the Caribbean, SCTLD has been devastating for P. strigosa populations, recent estimates indicate that 50-100% of colonies of this species have been lost in Florida and Mexico (Thome et al, 2021;Williams et al, 2021;Alvarez-Filip et al, 2022). Severity and speed of disease progression do not only differ between species, but also among colonies of the same species, which suggests that colony health, environmental conditions, and perhaps a series of independent transmission events played essential roles in the disease progression dynamics at the reef scale (Guzmań-Urieta and Jordań-Dahlgren, 2021).…”

Management responses in Belize and Honduras, as stony coral tissue loss disease expands its prevalence in the Mesoamerican reef

“…Meyer et al (2019) notes the co-occurrence of other coral-stress events with the rapid and severe SCTLD infestations in Florida, including heat stress/bleaching and port dredging operations, and the suspended sediment and contaminant loading associated with dredging activity. In Mexico, the rapid spread of SCTLD across about 400 km of fringing reefs in close proximity to highly developed coastlines with well-known sewage contamination issues, adds anecdotal evidence to the linkage with anthropogenic stress (Alvarez-Filip et al 2022). To date, the only reef area in Mexico not yet experiencing SCTLD in Banco Chinchorro, which is virtually uninhabited other than park staff and fishers.…”

Coral reef erosion: In situ measurement on different dead coral substrates on a Caribbean reef

“…(Aronson and Precht 2001;Toth et al 2019). This has resulted in ecological shifts in the composition of coral communities toward those defined by the dominance of nonframework building species (Perry et al 2015;Cramer et al 2021;Alvarez-Filip et al 2022).…”