Nav: Home

Regular coral larvae supply from neighboring reefs helps degraded reefs recover

May 16, 2017

For reefs facing huge challenges, more coral larvae doesn't necessarily translate to increased rates of coral recovery on degraded reefs, a new Queensland study has showed.

The study, published today, was led by former University of Queensland School of Biological Sciences researcher Dr Christopher Doropoulos, now of CSIRO Oceans and Atmosphere, and involved collaboration with CSIRO, the University of Queensland, and Griffith University.

"Overall, our research shows that excessively high or low densities of coral larvae do not contribute to reef recovery," said Dr Doropoulos.

"When larval supply is too low, corals tend not to attach to the reef because they have aggregative behaviour; they prefer to colonise in groups.

"On the other hand, when larval densities are extremely high, the post-settlement survival of corals is low because internal feedbacks regulate populations so they don't grow in excess."

The researchers used both laboratory and field studies to investigate how differing coral larval densities and habitat complexity influenced larval survival, settlement and post-settlement success.

They found recovery of coral populations was optimal where there are consistent supplies of coral larvae from neighbouring, healthy reefs, to areas of disturbed reefs with low abundances of competing seaweeds, and cryptic spaces for tiny corals to hide and grow.

Thus, Dr Doropoulos said a network of well-connected reefs with abundant herbivorous fish populations was needed to maintain long-term reef resilience.

"Coral colonisation involves three distinct life-history stages," he said.

"Firstly, corals are transported as tiny larvae following mass annual spawning events.

"Secondly, the larvae transition from the water column to undergo metamorphosis and settle on to the reef, after which time they can no longer swim.

"Finally, the minute corals need to defend themselves against predators and competitors to grow and survive into colonies that build coral reefs.

"Each of these three stages is considered a 'recruitment bottleneck', so quantifying how well corals can transition through each stage is key to understanding how well reefs can recover following a disturbance."

UQ Marine Spatial Ecology Lab PhD student Nicolas Evensen said colonisation by tiny coral larvae was a key process that promoted reef recovery after degradation.

"The findings will be important for future reef management," Mr Evensen said.

"The recolonisation of coral larvae is a key attribute of reef resilience, and is becoming increasingly important with the cover of reef-building corals declining globally."

The research is published in The Royal Society Open Science.
-end-


University of Queensland

Related Corals Articles:

Climate change refuge for corals discovered (and how we can protect it right now)
WCS scientists have discovered a refuge for corals where the environment protects otherwise sensitive species to the increasing severity of climate change.
Some -- but not all -- corals adapting to warming climate
A new WCS study reveals evidence that some corals are adapting to warming ocean waters -- potentially good news in the face of recent reports of global coral die offs due to extreme warm temperatures in 2016.
Stanford biologists identify ancient stress response in corals
Monitoring a newly discovered group of genes in coral could predict when they are under stress and might bleach.
A warm relationship between corals and bacteria
KAUST shows the close association between corals and bacteria may help protect the coral animal from heat stress.
Corals much older than previously thought, study finds
Coral genotypes can survive for thousands of years, possibly making them the longest-lived animals in the world, according to researchers at Penn State, the National Marine Fisheries Service and Dial Cordy & Associates.
Corals survived Caribbean climate change
Corals in the genus Orbicella survived previous temperature changes in the Caribbean and may be able to survive future climate change events as well.
Study reveals corals' influence on reef microbes
As they grow, corals are bathed in a sea of marine microbes, such as bacteria, algae, and viruses.
Looking back into the future: Are corals able to resist a declining pH?
Tropical Porites corals adjust their internal pH to enable themselves to form calcium carbonate and grow under elevated carbon dioxide concentrations -- even for a longer period of time.
Heat sickens corals in global bleaching event
Australian scientists report that many surviving corals affected by mass bleaching from high sea temperatures on the northern Great Barrier Reef are the sickest they have ever seen.
Corals most important for building reefs are now in sharp decline
Staghorns, the very corals responsible for establishing today's reefs, are now some of the most threatened coral species due to climate change and other man-made stressors.

Related Corals Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Jumpstarting Creativity
Our greatest breakthroughs and triumphs have one thing in common: creativity. But how do you ignite it? And how do you rekindle it? This hour, TED speakers explore ideas on jumpstarting creativity. Guests include economist Tim Harford, producer Helen Marriage, artificial intelligence researcher Steve Engels, and behavioral scientist Marily Oppezzo.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".