Once a year on a night with a full moon, corals in the Florida Keys release reproductive cells and begin the process of bringing new coral into life.

Recently, however, this process has been disrupted by a disease known as white plague that’s killing off the reefs, according to the Los Angeles Times.

White plague causes coral reefs to rapidly shed tissue and was first discovered in 1977 in the Florida Keys. In 2014, it started to become a major threat for unknown reasons, but scientists knew that action had to be taken, the Times reports. In the Caribbean, for example, large swaths of coral have been destroyed by the disease.

To prevent further decline in the Florida Keys, a team of scientists from the Florida Aquarium recruited a team of divers and traveled to the keys on Aug. 9 for an important two-week trip. They collected 150,000 coral eggs and sperm, and used in vitro fertilization —through which the scientists fertilize the egg in a dish — to help the coral reproduce.

Take Action: Ensure All Communities Can Withstand Climate Disaster

Once the eggs were fertilized, some were released immediately back into the ocean and other were placed in different labs to grow before being released back into the ocean.

The goal is to repopulate reefs more effectively and efficiently. When coral release their gametes, fish often eat them. By capturing them and fertilizing them, eggs may produce more coral in the long term and hopefully keep the reefs healthy.

Corals are uniquely susceptible to disease because they grow so slowly, at a rate of 0.3 to 2 centimeters per year, so a disease can wipe out hundreds of years of progress in a season, according to the Los Angeles Times.

Research has shown that white plague is most prevalent in corals that have already experienced bleaching. Coral bleaching is “when corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white,” according to the National Ocean Service.

Read More: Plastic Is Causing Coral Reefs to Get Sick and Die

The primary driver of coral bleaching is climate change and the warming of ocean temperatures.

In recent years, over 25% of the globe’s coral reefs have been eradicated and if things stay on track, the majority of remaining reefs could be dead in 20 years, scientists told ABC News.