This December 2014 video says about itself:
In what has been described as the “world’s biggest orgy”, coral on Australia’s Great Barrier Reef has spawned in one of nature’s most amazing and rarely-seen shows. In an even rarer occurrence, the coral put on an encore performance, re-producing – or spawning – for the second time in two months, releasing millions of eggs and sperm into the waters of the Great Barrier Reef to fertilise. This almost unseen “split-spawning” event had marine scientists and tourists marvelling in delight.
From the University of Queensland in Australia:
Strange coral spawning improving Great Barrier Reef’s resilience
August 6, 2019
A phenomenon that makes coral spawn more than once a year is improving the resilience of the Great Barrier Reef.
The discovery was made by University of Queensland and CSIRO researchers investigating whether corals that split their spawning over multiple months are more successful at spreading their offspring across different reefs.
Dr Karlo Hock, from UQ’s School of Biological Sciences, said coral mass spawning events are one of the most spectacular events in the oceans.
“They’re incredibly beautiful,” Dr Hock said.
“On Australia’s Great Barrier Reef, all coral colonies typically spawn only once per year, over several nights after the full moon, as the water warms up in late spring.”
Study co-author Dr Christopher Doropoulos from the CSIRO Oceans & Atmosphere said sometimes however, coral split their spawning over two successive months.
“This helps them synchronise their reproduction to the best environmental conditions and moon phases,” he said.
“While reproductive success during split spawning may be lower than usual because it can lead to reduced fertilisation, we found that the release of eggs in two separate smaller events gives the corals a second and improved chance of finding a new home reef.”
The research team brought together multi-disciplinary skills in modelling, coral biology, ecology, and oceanography, simulating the dispersal of coral larvae during these split spawning events, among the more than 3800 reefs that make up the Great Barrier Reef.
They looked at whether the split spawning events more reliably supply larvae to the reefs, as well as whether the ability to exchange larvae among the reefs is enhanced by them.
UQ’s Professor Peter J. Mumby said split spawning events can increase the reliability of larval supply as the reefs tend to be better connected and have more numerous, as well as more frequent, larval exchanges.
“This means that split spawning can increase the recovery potential for reefs in the region.
“A more reliable supply of coral larvae could particularly benefit reefs that have recently suffered disturbances, when coral populations need new coral recruits the most.
“This will become more important as coral reefs face increasingly unpredictable environmental conditions and disturbances.”
Dr Hock said the research also revealed that the natural processes of recovery can sometimes be more resilient than originally thought.
“However, even with such mechanisms in place, coral populations can only withstand so much pressure,” he said.
“It all ends up being the matter of scale: any potential benefits from split spawning might be irrelevant if we don’t have enough coral on these reefs to reproduce successfully.
“Mitigating well-established local and global threats to coral reefs — like river runoffs and carbon dioxide emissions — is essential for their continued survival.”
The study between UQ, CSIRO and ARC Centre of Excellence for Coral Reef Studies was published in Nature Communications.
Scientists have completed a landmark study on how to save coral reefs in the Indian and Pacific Oceans: here.
GIANT ROCK COULD HELP HEAL BARRIER REEF A “raft” of floating pumice rock the size of Manhattan is drifting toward Australia, bringing along new marine life that could help with the recovery of the Great Barrier Reef’s corals, half of which have been killed in recent years as a result of climate change. [CNN]
The first documented discovery of ‘extreme corals’ in mangrove lagoons around Australia’s Great Barrier Reef is yielding important information about how corals deal with environmental stress, scientists say. Thirty-four species of coral were found to be regularly exposed to extreme low pH, low oxygen and highly variable temperature conditions making two mangrove lagoons on the Woody Isles and Howick Island potential ‘hot-spots’ of coral resilience: here.
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A new study into the recent history of the Great Barrier Reef has shown how it responds to rapid sea-level rise and other environmental stresses. The study, conducted at the University of Sydney’s research station at One Tree Island, has upended the established model of Holocene-era reef growth. Using unprecedented analysis of 12 new drilled reef cores with data going back more than 8000 years, the study shows that there have been three distinct phases of reef growth since the end of the Pleistocene era about 11,000 years ago: here.