Scientists selectively bred corals to boost their heat tolerance
Selective breeding boosts coral heat tolerance, but modest gains highlight the urgent need for climate action to protect reefs from warming oceans.
Coral reefs face mass mortality due to rising ocean temperatures. Scientists explore selective breeding to boost coral resilience but stress the need for climate action. (CREDIT: SeaLegacy)
Marine ecosystems face a crisis as rising ocean temperatures lead to more frequent and severe heatwaves. Coral reefs, known for their biodiversity and ecological importance, are among the most vulnerable. Marine heatwaves cause coral bleaching and mass mortality, threatening reef survival.
In response, scientists are exploring solutions like selective breeding to enhance coral resilience. While this approach shows promise, it also underscores the urgent need for global climate action.
Breeding Corals for Survival
For millennia, humans have selectively bred plants and animals to improve desirable traits. Now, this technique is being tested for nature conservation.
Researchers recently conducted the first trials to selectively breed adult corals for increased heat tolerance. This effort was spearheaded by Newcastle University’s Coralassist Lab in collaboration with international institutions.
The trials focused on two heat tolerance traits: resilience to short-term intense heat exposure and long-term moderate stress. Results revealed that selecting parent corals with higher heat tolerance improved the survival of their offspring under heat stress.
These findings suggest that coral heat tolerance has a genetic basis, with heritability estimates ranging between 0.2 and 0.3. This allows for measurable, though moderate, improvement within one generation.
Dr. Liam Lachs, a postdoctoral researcher at Newcastle University, emphasized that while selective breeding shows feasibility, it is not a standalone solution. “This work shows that selective breeding is feasible but not a silver bullet solution. Rapid reductions of global greenhouse gas emissions are an absolute requirement to mitigate warming and give corals an opportunity to adapt,” he said.
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The breeding trials highlighted both potential and limitations. Offspring from selectively bred corals displayed improved tolerance to heat stress, but the enhancements were modest. Specifically, heat tolerance improved by approximately 1°C-week, a figure insufficient to counteract the projected temperature rise under unabated global warming.
Moreover, the study found no genetic correlation between short-term and long-term heat tolerance traits. This suggests that the genetic controls for these traits may be independent. As Dr. Adriana Humanes, another lead researcher, explained, this poses a challenge for future interventions.
“Considerable work remains before selective breeding can be successfully implemented. A deeper understanding is needed to determine which traits to prioritize and how these traits are genetically correlated.”
The research underscores the complexity of coral adaptation. Traits such as heat tolerance are multivariate, influenced by numerous genetic factors, and dependent on the magnitude and duration of heat stress. These complexities complicate efforts to enhance coral resilience through breeding alone.
Implications for Coral Reef Conservation
Selective breeding offers a potential lifeline for corals, but its success depends on more than genetics. The method raises practical concerns about scaling interventions and ensuring their effectiveness.
For example, how many selectively bred corals must be introduced to wild populations to make a difference? Additionally, scientists must address risks such as trait dilution once corals are added to natural habitats.
Dr. James Guest, a researcher in coral reef ecology at Newcastle University, highlighted these challenges: “The results show that selective breeding could be a viable tool to improve population resilience. Yet, there are still many challenges that need to be overcome. How can we maximize responses to selection while ensuring there are no trade-offs?”
Selective breeding also requires reliable methods to identify heat-tolerant colonies for reproduction. However, if these assays fail to predict long-term survival under natural marine heatwaves, the utility of this approach could be compromised.
A Call to Action
While selective breeding offers hope, its modest gains are unlikely to keep pace with escalating ocean temperatures. The study's authors stress that breeding interventions must be paired with urgent climate action. Without significant reductions in greenhouse gas emissions, even the most heat-tolerant corals may struggle to survive.
The research, published in Nature Communications, marks an important proof of concept. It shows that breeding corals for heat tolerance is possible, but scaling the approach to safeguard entire reefs will require further innovation.
As Dr. Guest remarked, “Given the moderate levels of enhancement we achieved in this study, the effectiveness of such interventions will also depend on urgent climate action.”
Selective breeding is a promising tool in the fight to save coral reefs, but it cannot stand alone. By combining genetic interventions with global efforts to curb warming, there is hope for these vital ecosystems to endure.
Note: Materials provided above by The Brighter Side of News. Content may be edited for style and length.
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