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1. Heat-driven functional extinction of Caribbean Acropora corals from Florida’s Coral Reef

   https://doi.org/10.1126/science.adx7825  

   Manzello, Derek P; Cunning, Ross; Karp, Richard F; Baker, Andrew C; Bartels, Erich; Bonhag, Ryan; Borreil, Alexandra; Bourque, Amanda; Brown, Kristen T; Bruckner, Andrew W; et al (October 2025, Science)

   In 2023, a record-setting marine heat wave triggered the ninth mass coral bleaching event on Florida’s Coral Reef (FCR). We examined spatial patterns of heat exposure along the ~560-kilometer length of FCR and the mortality of two ecologically important, critically endangered reef-building corals. Sea surface temperatures were ≥31°C for an average of 40.7 days, leading to heat exposures 2.2- to fourfold higher than all prior years on record. In the Florida Keys and Dry Tortugas, 97.8 to 100% of theAcropora palmataandAcropora cervicorniscolonies died. Mortality was lower offshore southeast Florida (37.9%), reflecting cooler temperatures in this region. Since the late 1970s, multiple stressors had already reduced the ecological relevance ofAcroporain Florida, but the 2023 heat wave marks their functional extinction from FCR. 

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2. Coral mortality in a mass bleaching event influenced by proximity to diseased tissue and reef topography

   https://doi.org/10.1007/s00338-026-02928-6  

   Nivison, Camilla L; May, Christa R; Bourbonnais, Mari Ella; Shotz, Shannon; Basden, Isabelle; Deng, Deyan; Dixon, Shannon; Huang, Debao; Hulver, Ann Marie; Ayad, Mariam; et al (July 2026, Coral Reefs)

   Abstract Coral reefs of the Florida Keys experienced the hottest summer on record in 2023, causing mass bleaching and mortality of scleractinian corals. Sea surface temperatures remained above 31°C for 41 days, exceeding all prior records for the region. Branching corals fared especially poorly, especiallyAcropora palmata, which has now been deemed functionally extinct across the entire Florida Reef Tract. High temperatures and prolonged thermal stress were the major causes of mortality. Our study investigates additional stressors contributing to coral mortality during the heatwave. Using benthic imagery, we show that during bleaching, coral tissue death is accelerated by proximity to disease. Using a Cox proportional hazard model, we found that, compared to initially healthy tissue on the same colony, disease lesions and neighboring tissue had a 3.8 times and 1.5 times higher risk of death, respectively. We show that these two stressors, working at different spatial scales, acted synergistically to increase mortality. Furthermore, from ourin situreef structural measurements, we found that during bleaching, coral survival was greatest along the reef edge. The reef displaces water, resulting in faster local velocity, which we hypothesize reduces the boundary layer at the tissue-water interface and thus simultaneously enhances the removal of cytotoxic metabolic wastes and the opportunity for coral heterotrophic feeding. Our findings reinforce the importance of the interactive effects of disease and reef topography on coral mortality, and suggest that restoration efforts should focus on reef edges where the chance of survival is improved relative to the reef interior. 

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3. Coral larval settlement induction using tissue-associated and exuded coralline algae metabolites and the identification of putative chemical cues

   https://doi.org/10.1098/rspb.2023.1476  

   Quinlan, Zachary A.; Bennett, Matthew-James; Arts, Milou G.; Levenstein, Mark; Flores, Daisy; Tholen, Haley M.; Tichy, Lucas; Juarez, Gabriel; Haas, Andreas F.; Chamberland, Valérie F.; et al (October 2023, Proceedings of the Royal Society B: Biological Sciences)

   Reef-building crustose coralline algae (CCA) are known to facilitate the settlement and metamorphosis of scleractinian coral larvae. In recent decades, CCA coverage has fallen globally and degrading environmental conditions continue to reduce coral survivorship, spurring new restoration interventions to rebuild coral reef health. In this study, naturally produced chemical compounds (metabolites) were collected from two pantropical CCA genera to isolate and classify those that induce coral settlement. In experiments using four ecologically important Caribbean coral species, we demonstrate the applicability of extracted, CCA-derived metabolites to improve larval settlement success in coral breeding and restoration efforts. Tissue-associated CCA metabolites induced settlement of one coral species,Orbicella faveolata, while metabolites exuded by CCA (exometabolites) induced settlement of three species:Acropora palmata,Colpophyllia natansandOrbicella faveolata. In a follow-up experiment, CCA exometabolites fractionated and preserved using two different extraction resins induced the same level of larval settlement as the unfractionated positive control exometabolites. The fractionated CCA exometabolite pools were characterized using liquid chromatography tandem mass spectrometry, yielding 145 distinct molecular subnetworks that were statistically defined as CCA-derived and could be classified into 10 broad chemical classes. Identifying these compounds can reveal their natural prevalence in coral reef habitats and facilitate the development of new applications to enhance larval settlement and the survival of coral juveniles. 

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4. Fine‐scale structure among mesophotic populations of the great star coral Montastraea cavernosa revealed by SNP genotyping

   https://doi.org/10.1002/ece3.6340  

   Drury, Crawford; Pérez Portela, Rocío; Serrano, Xaymara M.; Oleksiak, Marjorie; Baker, Andrew C. (June 2020, Ecology and Evolution)

   Abstract Mesophotic reefs (30‐150 m) have been proposed as potential refugia that facilitate the recovery of degraded shallow reefs following acute disturbances such as coral bleaching and disease. However, because of the technical difficulty of collecting samples, the connectivity of adjacent mesophotic reefs is relatively unknown compared with shallower counterparts. We used genotyping by sequencing to assess fine‐scale genetic structure of Montastraea cavernosa at two sites at Pulley Ridge, a mesophotic coral reef ecosystem in the Gulf of Mexico, and downstream sites along the Florida Reef Tract. We found differentiation between reefs at Pulley Ridge (~68 m) and corals at downstream upper mesophotic depths in the Dry Tortugas (28–36 m) and shallow reefs in the northern Florida Keys (Key Biscayne, ~5 m). The spatial endpoints of our study were distinct, with the Dry Tortugas as a genetic intermediate. Most striking were differences in population structure among northern and southern sites at Pulley Ridge that were separated by just 12km. Unique patterns of clonality and outlier loci allele frequency support these sites as different populations and suggest that the long‐distance horizontal connectivity typical of shallow‐water corals may not be typical for mesophotic systems in Florida and the Gulf of Mexico. We hypothesize that this may be due to the spawning of buoyant gametes, which commits propagules to the surface, resulting in greater dispersal and lower connectivity than typically found between nearby shallow sites. Differences in population structure over small spatial scales suggest that demographic constraints and/or environmental disturbances may be more variable in space and time on mesophotic reefs compared with their shallow‐water counterparts. 

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5. Growth rates of coral reefs peaked at 25 °C through the Holocene

   https://doi.org/10.1371/journal.pone.0342527  

   Macedo, Tonya; van_Woesik, Robert (March 2026, PLOS One)

   Mayfield, Anderson B (Ed.)

   For millennia, corals have built coral-reef structures upon the remains of past generations of coral skeletons, forming the world’s most diverse marine ecosystems. Yet, ocean warming and regional and local disturbances are reducing the capacity of coral reefs to grow and keep pace with sea-level rise. Understanding which environmental and climatic conditions influenced reef growth in the past, when human populations were small, may help us understand how reefs respond to contemporary environmental changes. Using coral cores dating back 11,700 calibrated years before present (yr BP) from 291 sites across the Pacific, Indian, and Atlantic Oceans, we examined the relationships between seven environmental and climatic variables and coral-reef growth using a spatial-temporal Bayesian mixed model and a deep-learning neural-network analysis. Our results show a positive relationship between the rate of change in sea level and reef growth. Reef growth responded nonlinearly to sea-surface temperature, peaking at ~25 °C, during the Holocene Thermal Maximum, between ~7,000 and ~5,500 yrs BP. During this period, atmospheric carbon dioxide (CO₂) concentrations were ~325 parts per million (ppm) by volume. Our findings reveal that atmospheric CO₂levels currently exceeding 335 ppm, combined with sea-surface temperatures and modern marine heatwaves, are less than optimal for contemporary coral-reef growth, inhibiting their ability to keep pace with sea-level rise. 

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