Corals around the world are dying from ocean heat, but scientists just discovered that four simple treatments might help them survive. Researchers in the Red Sea tested hydrogen, phosphate, ammonium, and probiotics on two types of coral after a heat wave. All four treatments helped corals survive better—some increased survival by up to 40%. This is exciting news because it suggests we might have practical tools to protect coral reefs from climate change. The treatments are affordable and could be used in reef management programs to help corals bounce back from heat damage.

The Quick Take

  • What they studied: Can four different treatments help corals survive and recover after being exposed to dangerously hot water?
  • Who participated: Two species of hard corals (Acropora and Pocillopora favosa) from the Red Sea were tested in laboratory conditions for 48 hours after experiencing a natural heat stress event in 2023.
  • Key finding: All four treatments improved coral survival. Phosphate and ammonium were the most effective, increasing survival by 40% for both species, while phosphate and ammonium together achieved 100% survival in one species.
  • What it means for you: If you care about ocean health and coral reefs, this research suggests there are practical, affordable ways to help corals survive climate change. However, these are early-stage results from short lab tests, so more research is needed before widespread use.

The Research Details

Scientists conducted a controlled experiment in the laboratory using two common coral species from the Red Sea. After a natural heat stress event in 2023, they collected corals and exposed them to four different treatments plus a control group (no treatment) for 48 hours. Each treatment was tested separately: hydrogen gas, phosphate (a nutrient), ammonium (another nutrient), and probiotics (beneficial bacteria). The researchers measured three things: how many corals survived, how colorful they stayed, and how well their photosynthesis (the process they use to make food) worked.

This type of experiment is called a controlled trial because it compares treated corals to untreated corals under identical conditions. By keeping everything the same except the treatment, scientists can determine whether the treatment actually caused the improvement. The 48-hour timeframe allowed researchers to see immediate effects of the treatments on stressed corals.

This research approach is important because it tests practical solutions that could actually be used in real reef management. Rather than just studying what happens naturally, the scientists tested specific interventions that could be applied to help corals. The short-term nature of the experiment allowed them to see quick results, which is valuable for understanding how these treatments work at the cellular level.

This study was published in Scientific Reports, a reputable peer-reviewed journal, which means other scientists reviewed the work before publication. However, readers should know that the sample size wasn’t specified in the abstract, and the experiment only lasted 48 hours. Long-term effects are unknown. The study was conducted in laboratory conditions, which may not perfectly match what happens in the ocean. These are important limitations to consider when thinking about real-world applications.

What the Results Show

All four treatments improved coral survival compared to the control group. Hydrogen increased survival by 25% for Acropora corals and 40% for Pocillopora favosa. Phosphate and ammonium were equally effective, both increasing survival by 40% for both coral species. Remarkably, when phosphate and ammonium were used together on Acropora corals, they achieved 100% survival—meaning every single coral survived.

Beyond just survival, the treatments also improved how the corals looked and functioned. Phosphate and ammonium enhanced the color of Pocillopora favosa corals and improved their photosynthetic efficiency (how well they could make food from sunlight). Probiotics increased survival by 20% for Acropora and 40% for Pocillopora favosa, while also improving photosynthetic efficiency in both species.

These results suggest that different treatments work better for different coral species. Phosphate and ammonium appear to be the most powerful interventions, while probiotics and hydrogen also show promise. The fact that multiple treatments worked suggests there may be different biological pathways through which corals can recover from heat stress.

An important secondary finding is that the treatments didn’t just keep corals alive—they also helped them maintain their health and function. Improved photosynthetic efficiency means the corals could continue producing energy even after heat stress. Improved coloration suggests the corals were maintaining their symbiotic algae (zooxanthellae), which are essential for coral survival. These secondary benefits indicate that the treatments may help corals not just survive in the short term but also recover more completely.

This research builds on previous studies showing that corals can be helped through various interventions. The novelty here is testing multiple potential treatments side-by-side after a real heat stress event. Previous research has explored some of these treatments individually, but this comprehensive comparison in a realistic scenario (following an actual heat wave) provides new insights. The results align with growing evidence that targeted interventions can enhance coral resilience to climate change.

Several important limitations should be considered. First, the experiment only lasted 48 hours, so we don’t know if the benefits continue over weeks or months. Second, the study was conducted in laboratory conditions, which are very different from the complex ocean environment. Third, the sample size wasn’t specified, making it unclear how many coral colonies were tested. Fourth, we don’t know the long-term effects on coral reproduction or genetic health. Finally, this study tested treatments on corals that had already experienced heat stress; it’s unclear whether these treatments would prevent bleaching if applied before heat exposure. These limitations mean the results are promising but preliminary.

The Bottom Line

Based on this research, there is moderate evidence that phosphate, ammonium, hydrogen, and probiotics may help corals survive heat stress. However, these are early-stage findings from short-term lab experiments. Confidence level: Moderate for short-term survival benefits; Low for long-term effectiveness. Recommendation: These treatments warrant further testing in larger, longer studies and in controlled reef environments before widespread ocean application. Reef managers interested in coral conservation should monitor this research closely.

This research matters most to marine biologists, reef managers, and conservation organizations working to protect coral reefs. Aquarium professionals and coral restoration programs may find these treatments useful. Climate scientists and policymakers should care because it suggests practical tools exist for climate adaptation. General ocean lovers should care because it offers hope that we can help corals survive climate change. However, this research should not be used as a reason to delay climate change mitigation—protecting corals ultimately requires reducing greenhouse gas emissions.

In this 48-hour study, benefits appeared immediately. However, realistic expectations for ocean application are much longer. If these treatments are eventually used in reef management, it would likely take weeks to months to see meaningful recovery in wild coral populations. Long-term benefits (years to decades) are completely unknown at this point.

Want to Apply This Research?

  • If you’re involved in coral conservation efforts, track the health status of treated vs. untreated coral colonies over time using a simple scoring system: survival rate (% alive), color intensity (scale of 1-5), and estimated photosynthetic health (visual assessment). Record these measurements weekly or monthly depending on your monitoring schedule.
  • For conservation app users: Set reminders to monitor local reef conditions and water quality parameters (temperature, nutrient levels) that might indicate when intervention treatments could be beneficial. Log any coral bleaching events in your area to contribute to citizen science databases that track heat stress patterns.
  • Establish a baseline assessment of coral health before any treatment application. Then monitor treated areas monthly for at least 6 months, comparing survival rates, coloration, and growth between treated and untreated control areas. Document water conditions (temperature, pH, nutrient levels) alongside coral health metrics to understand which conditions make treatments most effective.

This research describes early-stage laboratory findings on coral stress recovery and should not be considered definitive guidance for ocean management. These experiments were conducted in controlled 48-hour laboratory conditions and may not reflect real-world ocean environments or long-term outcomes. Before any large-scale application of these treatments to natural reefs, significantly more research is needed, including longer-term studies, field trials, and environmental impact assessments. This information is for educational purposes and should not replace consultation with marine biologists and reef management experts. These findings do not reduce the critical importance of reducing greenhouse gas emissions to address the root cause of coral heat stress.