Anna Hartz
Rising ocean temperatures are putting many reefs under growing pressure, leaving scientists searching for new ways to help them survive.
Coral reefs are among the world’s most important ecosystems. They provide food and shelter for countless marine species and help protect coastlines from storms.
Fast moving climate change
As global warming continues, extreme marine heatwaves are causing widespread damage to tropical coral reefs.
Most corals depend on tiny algae that live inside their tissues. These algae produce energy through photosynthesis, allowing corals to grow and build the hard skeletons that form coral reefs, writes Videnskab.
Scientists say corals must become more tolerant of heat if they are to survive in warmer oceans. Natural adaptation can happen over many generations, but researchers worry that climate change is moving faster than corals can keep up.
Because of this, scientists are studying a method known as guided evolution. One of the most promising approaches is selective breeding. The goal is to produce future generations of corals that can better survive extreme heat.
Is the answer selective breeding?
A new study followed a population of farmed corals in Palau, an island nation in the western Pacific Ocean, over an eight-year period.
The researchers examined the genetic basis of heat tolerance as well as other important traits, including growth, energy storage and reproduction.
They found that simply choosing corals that survived a heatwave is not always the best strategy. Some corals may survive because they were in a cooler location or had larger energy reserves rather than because of stronger genetics.
Instead, scientists looked at whether entire coral families survived or died under heat stress. This gives a better picture of which corals carry genes linked to heat tolerance.
The team also exposed corals to several different temperature tests. They discovered that some laboratory heat tests were better than others at predicting how corals would survive real marine heatwaves.
Computer simulations suggested that selective breeding could improve heat tolerance over several generations. However, the process would require testing large numbers of corals and breeding only the strongest individuals while maintaining enough genetic diversity.
The researchers say guided evolution could become an important tool for protecting coral reefs. However, they stress that it cannot replace efforts to reduce greenhouse gas emissions. Slowing global warming remains the most important step if coral reefs are to survive in the decades ahead.
Sources: Videnskab
