A team of marine scientists from Guangxi University has made a significant advancement in coral conservation, coinciding with World Oceans Day.

Situated off the coast of Weizhou Island in the Guangxi Zhuang Autonomous Region, the researchers have developed a method to induce large-scale coral spawning in higher latitude regions, enabling controlled sexual reproduction of corals.

This technique is critical for restoring coral populations threatened by climate change."We’ve transitioned from merely planting corals to breeding them, facilitating the creation of robust underwater ecosystems," stated Huang Wen, an associate professor at the School of Marine Sciences.

Coral reefs, often likened to the "tropical rainforests of the ocean," contribute to biodiversity, housing over 25% of marine species despite covering only 0.2% of the seafloor.

Coral health has declined globally, with extensive bleaching events driven by rising ocean temperatures and human activities.

The situation around Weizhou Island reflects this trend, with coral cover plummeting from 60% in the 1980s to under 5% by 2015.

In 2015, the Guangxi University team embarked on a comprehensive initiative to rejuvenate these reefs.

The scientists cultivated coral colonies in laboratories, salvaged natural coral fragments, and painstakingly anchored them in seed trays for divers to position on the seabed.

Their efforts have led to the establishment of a 2,000-square-meter restoration zone where coral cover has quadrupled to 20% over three years.

The team has installed 1,520 artificial reefs and transplanted over 80,000 coral colonies, restoring approximately 30 hectares of reef habitat.

Despite these achievements, researchers assert that successful restoration requires natural coral reproduction.

Gong Sanqiang, another associate professor, emphasized, "Sexual reproduction enhances genetic diversity and bolsters resilience against environmental changes." Coral spawning, a brief phenomenon that occurs annually for only a few hours, necessitated the development of techniques to precisely identify spawning windows through the monitoring of gonadal development and seawater conditions.

In mid-May, the team identified a 72-hour "golden window" for coral spawning.

Divers captured images of corals releasing pink reproductive bundles while other members of the team implemented water flow control systems and induced spawning with specialized methods, gathering a notable quantity of eggs and sperm.

In the laboratory, researchers meticulously separated and preserved these gametes in liquid nitrogen, establishing a crucial resource for future restoration efforts.

Yu Kefu, the team leader and dean of the School of Marine Sciences, likened the liquid nitrogen tanks to a "Noah's Ark" for corals, asserting their potential pivotal role in upcoming conservation endeavors.