Can coral breeding save the reef ecosystem?


 |  Biodiversity/Conservation

Bright-coloured and nurturing to a variety of marine organisms, coral reefs cover only around 0.5 % of the world’s surface, yet are vital to 25% of all marine life. Despite their importance, coral reefs are in trouble – they are facing bleaching, habitat loss, and ocean acidification. With these problems, scientists are working hard to find solutions, including lab-created coral colonies to transplant into the ocean. But can this process actually be successful? 

Photo by Veronica Reverse on Unsplash

Before we dive into the world of coral breeding, let’s clarify what kind of organism these stunning creatures are. Corals are invertebrates with algae living in their tissues, giving corals their various bright colours. Both the animal (invertebrate) and plant (algae) part of coral live in symbiosis.  The reason coral reefs are dying is because algae can’t survive the warmer and more acidic oceans, which leaves just the bare white skeleton of coral, known as bleaching. 

Coral in Labs and Seas Across the World

Coral breeding labs contain various tanks, each of which has its own set of conditions, mimicking the future oceanic conditions. These conditions are determined from climate change models in efforts to breed adaptive coral reefs. 

To better understand the science and successes of coral breeding, it helps to explore a few examples from around the world. 

There’s been an achievement made by a group of scientists in Germany who successfully induced sexual reproduction in stony corals for the first time. Previously, asexual reproduction through means of fragmentation was the only successful method. The research team witnessed young lab-curated corals spawn at nearly the same time with a high rate of fertilization, as the corals back home in the Pacific Ocean, suggesting they are in-sync. 

In a coral hotspot, off the north-eastern coast of Australia, hybrid corals placed  in the Great Barrier Reef have demonstrated the ability to cope with the environment and are helping create a more resilient reef ecosystem.

There are attempts to mass produce corals using a premade coral skeleton, which The Coral Maker (the team behind this project), believes can make 4,000 coral skeletons per day. Placing live coral into a premade skeleton rapidly increases coral growth by not having to form its skeleton from scratch. These skeletons are later moved to the ocean, where they will flourish into a healthy coral reef ecosystem. 

Bright Aspirations?

Usually corals bleach when algae dies from the tissue due to warmer or more acidic conditions. However, some reefs, like the one pictured below, have started to glow in response to bleaching.

Palawan, Philippines. Ryan Goehrung/University of Washington.

This phenomenon is an urgent signal that there is either a temperature increase  or nutrient stress, but at the moment it is unclear why some corals glow when bleached rather than turn completely white. 

New Caledonia. Credit: The Ocean Agency 

In addition to corals demonstrating fluorescence, some have shown to have abilities to recover from bleaching, where they seem to have ‘reborn’. What researchers found in the Mediterranean, is that these animals have shrunk in size as a way of coping, and with time, were able to bring life back to the previously dormant reef. Although these corals are showing signs of recovery, corals grow slowly, and with climate change increasing in severity, coral reef ecosystems  may not survive if not given enough time to mature.

With the help of breeding, human support and innovation, coral reef ecosystems have proven to recover and thrive in spectacular ways, providing hope for future generations of coral colonies.

Doing Your Part

You don’t have to be a scientist in a lab to contribute to healthier reefs, there are more accessible and simple ways to do your part – here are a few:

  • Wear a rashguard or use mineral-based sunscreen instead of  harsh sunscreen, which can be damaging to marine life
  • Minimize or eliminate fertilizer use
  • When diving, follow the practice of “don’t touch”
  • Help spread the message that coral reef ecosystems are in danger
  • Picking up trash along shores 
  • Reduce greenhouse gases – walk, bike or transit to your destination