Corals are some of the most critical habitats in the oceans. They create a 3D structure on which life can flourish and develop.
They represent less than 1% of the ocean floor, yet, coral reef host 25%+ of all marine life and are believed to have the highest ecosystem biodiversity!
The problem is that corals are fragile and die when their environment changes (e.g., sea temperature increases, changes in light exposure etc.), and, you guessed it... climate change isn't making corals life any easier.
The rise in ocean temperature and the acidification of oceans as consequences of anthropogenic (read "human-caused") greenhouse gas emissions cause stress on corals, killing them in so-called “bleaching events” (i.e., when corals die, they become white).
A dead coral becomes crumbly, and the 3D structure it formed collapses to become a flat, lifeless ocean floor.
To restore reefs, scientists use different techniques.
🔞 Restoring coral reef with Asexual methods, i.e., “cut and plant.”
Corals can reproduce asexually, like plants (though they are animals!). It is possible to restore reefs by removing small parts from healthy corals and transplanting them to a hard substrate (like a degraded reef structure). Just like you'd cut a piece of a plant to grow it somewhere else.
While this method allows for "quick" restoration and a quick increase in coral coverage in degraded reefs, it has a few drawbacks. One is that it does not create genetically rich coral reefs and instead "duplicates" the genetic code of specific specimens. This lack of genetic diversity is bad for the reefs' long-term resilience.
🍆🍑 Restoring coral reef with sexual methods
Coral spawning is a synchronized breeding event during which corals reproduce simultaneously. During spawning, corals release lots of eggs and sperm into the water that must match those of the same species to fertilize. However, spawning is a rare event that only happens under specific conditions.
Studying coral spawning events, scientists can capture specimens and simulate specific environmental conditions to stimulate them and make them spawn multiple times a year. Generating more frequent natural sexual cycles for corals allows researchers to increase reproduction and restore reefs by building coral colonies with high genetic diversity, which is essential to increase the resilience of these corals against climate change and other threats.
TL;DR:
Corals are the foundation of marine life. When they die, they take all their inhabitants 🐠 with them.