Trophic Antioxidant Transfer as a Measure for Scalable Coral Conservation Strategies

Coral reefs are increasingly threatened by elevated seawater temperatures associated with heatwaves and El Niño events. These phenomena challenge conventional management practices, highlighting an urgent need for innovative interventions to enhance reef resilience. Investigating the role of oxidative stress-one of the main explanations for coral bleaching-is central to these efforts, as excessive production of reactive oxygen species can impair coral physiology, disrupt the coral-algal symbiosis, and ultimately lead to mortality. Here, we investigated an antioxidant-rich food web approach by feeding the reef-building coral Stylophora pistillata with Artemia that had been pre-fed with (i) low-cost and in-house-produced pellets containing curcumin, fucoxanthin, astaxanthin, vitamins C or E, or (ii) the phytoplankton species Pavlova lutheri, Symbiodinium sp., Nannochloropsis sp., Dunaliella salina or Synechococcus sp. Curcumin and the microalga P. lutheri offered the best protection to corals against oxidative stress, and represent the best candidates for potential scalable coral conservation interventions involving targeted feeding of antioxidants. Curcumin pellets offer a streamlined alternative to P. lutheri by eliminating the need for multi-stage microalgal culturing. Direct enrichment of Artemia with antioxidant-rich pellets simplifies production and may provide a cost-effective, scalable strategy to enhance coral resilience to oxidative stress, bleaching and potential mortality.