{
  "id": 6857206,
  "title": "Diel thermal variability does little to mitigate bleaching in two endangered coral holobionts",
  "url": "https://urgent.news/2026/09/11/diel-thermal-variability-does-little-to-mitigate-bleaching-in-two",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-11T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.09.11.750923v1?rss=1"
  },
  "original_language": "en",
  "account": "A study has demonstrated that diurnal temperature fluctuations (DTV) do not significantly enhance coral resistance to bleaching, even in endangered coral species. Researchers employed a common garden experiment with two endangered coral species, Orbicella franksi and O. faveolata, exposing them to 90 days of DTV (26°C ± 2.4°C day-1) compared to stable conditions (26°C). Despite the DTV, neither coral species showed any significant physiological or gene expression changes or shifts in their microbial communities (Symbiodiniaceae algae and bacteria).\n\nThe critical finding was that when the corals were subsequently exposed to a heat challenge (32°C for 15 days), both species experienced widespread physiological and gene expression responses, regardless of whether they had been primed with DTV. This suggests that DTV priming did not confer any additional thermal stress resistance to the corals.\n\nA systems biology analysis revealed two sets of gene modules. Firstly, convergent gene modules were present in both coral species, suggesting shared homeostatic mechanisms. Secondly, divergent gene modules were identified, with O. faveolata exhibiting enrichment in catabolic processes and O. franksi showing classic protein folding functions under thermal stress. These results indicate that while congeneric coral species can display different gene expression responses to thermal challenges, DTV priming alone does not enhance their ability to resist thermal stress. The authors conclude that other environmental factors, which often vary alongside DTV on a reef, may have a more substantial influence on bleaching mitigation.",
  "summary": "Research has shown that tropical corals inhabiting warmer, more thermally variable reef environments often exhibit reduced bleaching. However, the influence of diel thermal variation (DTV) is rarely tested experimentally independent of changes in mean temperature, and few studies have explored responses of coral hosts together with their associated microbial consortia (Symbiodiniaceae algae and…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}