Can Science Save Our Coral Reefs? | OpenMind

Mass Global Coral Bleaching Event Threatens Sustainable Development Goals

Our planet is currently experiencing its fourth mass global coral bleaching event, with soaring ocean temperatures causing corals in the three major ocean basins to bleach. This event, predicted to be worse than the previous one from 2014-2017, poses a significant threat to the Sustainable Development Goals (SDGs) set by the United Nations.

• The loss of coral reefs endangers a quarter of all marine life and disrupts ecosystems.
• If current ocean warming and acidification trends continue, most coral reefs could go extinct by 2050.
• Researchers are determined to find solutions to save coral reefs and achieve SDG 14: Life Below Water.

What are Corals?

Corals are animals related to sea anemones or jellyfish. They form colonies made up of genetically identical polyps that use calcium carbonate to construct cup-shaped structures. These colonies can grow into the largest biological structures on Earth, such as the Great Barrier Reef in Australia.

Corals also have a symbiotic relationship with tiny marine algae called zooxanthellae. The algae live in the polyps’ tissues and provide them with compounds for photosynthesis, while the polyps offer a protected environment. This relationship gives corals their unique colors.

However, when water temperatures rise, the algae produce toxins harmful to the corals. The polyps expel the algae, causing the coral to bleach and turn white. While bleached coral is not dead, it becomes vulnerable to disease and starvation without its primary energy source. If temperatures decrease quickly enough, the algae can recolonize the polyps and the coral may recover over time.

Can Science Restore Damaged Reefs?

Various conservation initiatives aim to restore damaged reefs, with two notable methods being cloning and Coral IVF.

• Cloning involves growing micro-fragments of live coral in tanks on land before reintroducing them to damaged reefs. While effective, this approach is expensive, labor-intensive, and lacks genetic diversity.
• Coral IVF captures coral eggs and sperm during spawning and uses assisted reproduction techniques to create genetically diverse individuals. These larvae are then attached to seeding units or directly dispersed over damaged reefs.

Challenges and Controversies

There are ongoing challenges and controversies surrounding reef restoration efforts:

• Genetically modifying corals or zooxanthellae to enhance thermal tolerance is a promising but complex task with potential unintended consequences.
• Some experts argue that restoration projects are a distraction from addressing the root cause of coral reef decline: climate change.

The Future of Coral Reefs

A breakthrough in coral cryopreservation techniques offers hope for the future. Researchers have successfully frozen and revived coral fragments using a method called isochoric vitrification. This technique, if widely deployed, could secure the genetic diversity of coral reefs and contribute to SDG 14.

Ultimately, the fate of coral reefs rests on our ability to reduce carbon emissions and address climate change. Without significant progress in these areas, the hope of saving corals may rely on future scientists and cryogenically frozen genetic material stored in biorepositories worldwide.

Neil Larsen