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:

New study measures how much of corals' nutrition comes from hunting
When it comes to feeding, corals have a few tricks up their sleeve.
Corals take control of nitrogen recycling
Corals use sugar from their symbiotic algal partners to control them by recycling nitrogen from their own ammonium waste.
Extreme mangrove corals found on the Great Barrier Reef
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.
Stony corals: Limits of adaption
Corals have been dominant framework builders of reef structures for millions of years.
How to protect corals facing climate change
The best way to protect corals threatened by climate change is to conserve a wide range of their habitats, according to a study in Nature Climate Change.
New study finds distinct microbes living next to corals
Symbiotic algae living inside corals provide those animals with their vibrant color, as well as many of the nutrients they need to survive.
New study measures UV-filters in seawater and corals from Hawaii
Scientists have completed the first comprehensive assessment of UV-filters in surface seawater, sediment, and coral tissue from multiple coral reefs around the island of Oahu, Hawaii.
Climate change could make corals go it alone
Climate change is bad news for coral reefs around the world, with high ocean temperatures causing widespread bleaching events that weaken and kill corals.
Corals light the way to a healthy partnership
Corals know how to attract good company. New research finds that corals emit an enticing fluorescent green light that attracts the mobile microalgae, known as Symbiodinium, that are critical to the establishment of a healthy partnership.
Could algae that are 'poor-providers' help corals come back after bleaching?
How much of a reef's ability to withstand stressful conditions is influenced by the type of symbiotic algae that the corals hosts?
More Corals News and Corals Current Events

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

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.