Corals must be close to reproduce

Dec. 18 () –

A new study reveals that corals must be only a few meters away from each other to reproduce successfully, which leaves them vulnerable in a warming world.

International research, led by Professor Peter Mumby of the University of Queensland, measured the success of a natural spawning event in March this year.

“In what was a surprise, we saw that the corals needed to be within 10 meters of each other, and preferably closer, for fertilization to occur,” Professor Mumby said. in a statement.

“We knew the corals couldn’t be too far apart, but we found they had to be closer than we expected. The impacts of climate change, such as bleaching, are killing and reducing the density of corals, so we are concerned that the individuals end up too far apart to reproduce successfully.

To quantify breeding success, the team placed containers over 26 coral colonies on a reef in Palau, Micronesia, during a time when corals, mostly hermaphroditesthey released eggs and sperm.

“The containers captured some of the eggs from each coral and went to the surface where they followed the tide,” Professor Mumby said.

“Although the eggs could not escape, sperm could enter the container and fertilize the eggs. After an hour of drifting, the proportion of fertilized eggs for each type of coral was noted along with the distance to similar established corals.”

Fertilization averaged 30% when the corals were very close, but decreased to less than 10% at a separation of 10 meters and It was practically zero at 20 meters.

Co-author Dr Christopher Doropoulos of CSIRO, Australia’s national science agency, said coral reproduction was fundamental for the resilience and evolution of the population.

“In the future, we may need to help corals continue this key part of their lives. Understanding the importance of local neighborhoods provides tangible targets for interventions such as coral restoration,” he explained.

“The ideal would be to monitor coral density in important locations and carry it out to return it to the levels required for successful reproduction,” he added.

The research is published in PNAS (Proceedings of the National Academy of Sciences).