The study was led by the Coral Vivo Project, with participation from dozens of researchers affiliated with 20 institutions – including 15 Brazilian public universities, three Brazilian NGOs, one federal agency, and one French university. “The beauty of this work, despite describing something very sad, is the effort we made to bring together the Brazilian scientific community to document what’s happening and to alert Brazilian society,” says Mies, who is the research coordinator for the Coral Vivo Project. Ninety researchers signed the scientific article published in Coral Reefs, 32 of whom are affiliated with USP.
The 18 monitored sites are not the only ones where bleaching or mortality occurred, but they serve as a representative sample of what happened on a large scale along the Brazilian coast in 2024. According to the scientists, the heterogeneity of bleaching impacts reflects the condition of Brazilian reef ecosystems, which are extremely diverse in terms of species, environmental characteristics, and oceanographic conditions. The reefs in the Northeast are very different from those in the Southeast, for example, and even geographically close locations can differ significantly in species diversity, substrate type, depth, water clarity, and exposure to local threats such as pollution, overfishing, and unregulated tourism.
“There’s no way all corals in Brazil will respond the same way [to warming], because the reefs are different,” summarizes Destri. This scenario contrasts sharply with places like Australia or the Caribbean, where the latitudinal gradient is much smaller and environmental conditions are more homogeneous across reefs.
In the reefs of the South and Southeast, for instance, more robust coral species prevail – species accustomed to adverse environmental conditions such as high turbidity [a measure of the cloudiness or haziness of a fluid] and constant temperature fluctuations. This may help explain their greater resilience to bleaching effects. However, this does not mean they are immune to mortality in future events.
Across all surveyed areas, the overall reduction in live coral cover was 5%. The species with the highest mortality rates were Scolymia wellsii (66% reduction), Millepora alcicornis (54%), and Mussismilia harttii (28%) – commonly known as emerald coral, fire coral, and candle coral. The first is particularly concerning, as it had never bleached before; the other two are critical to the structural complexity of Brazilian reefs, upon which hundreds of species of fish and marine invertebrates depend for survival. The local extinction of any of these species could severely compromise ecosystem health, with potentially serious consequences for fisheries and tourism.
