What’s going on here?
Young corals grown via in vitro fertilisation (IVF) and planted in US, Mexican, and Caribbean reefs thrived during last year’s record marine heatwave, while older colonies faltered.
A study showed that 90% of IVF corals stayed healthy and vibrant, retaining their vital algae, compared to only 25% of older, non-IVF corals.
What does this mean?
Secore International, a reef conservation organisation, started the breeding of young corals through an IVF-like technique over five years ago.
Using this technique, researchers collect coral eggs and sperm, known as spawn, from healthy reefs. They use the coral spawn to rear millions of baby corals in specially designed floating pools and tanks. Once the corals mature, they are transplanted to damaged reefs to attach and grow.
The 2024 study on Sombrero Reef in the Dominican Republic compared young and old elkhorn corals after a heat stress event. While the young corals bred for restoration remained healthy and vibrant, most of the older corals that survived a previous disease outbreak perished due to bleaching.
The reasons for young corals’ heat tolerance are still not fully understood, but they may have a greater ability to acquire heat-tolerant algae. However, research director and lead author Margaret Miller, cautions that as these corals mature, their resilience to heat may diminish.
Why should we care?
Coral reefs are vital ecosystems that support diverse marine life, protect coastlines from erosion, and bolster local economies. Over half a billion people rely on reefs for food, income, and safety.
However, these precious ecosystems face serious threats, primarily from coral bleaching caused by rising ocean temperatures. In 2023, the fourth mass coral bleaching event occurred as ocean temperatures hit their highest levels on record. While corals can recover if conditions improve, complete ecosystem healing can take years.
Restoring coral populations is crucial, but as Miller emphasises, we must tackle the root causes of the climate crisis to truly protect these ecosystems for the long term.
Be curious!
- Find out how you can help restore the coral reefs through the Great Barrier Reef Foundation.
- Get involved in the Coral Watch’s coral health monitoring citizen science program and help collect valuable data on the state of coral reefs around the globe.
- From the Curious Archives: Learn more about the corals and coral bleaching
Featured image by Daniel Pelaez Duque, via Unsplash
