Please select your home edition
Edition
Barz Optics - Melanin Lenses

Being a bit 'fat' may spell the difference between life and death

by ARC Centre of Excellence for Coral Reef Studies on 15 Mar 2009
The evidence suggests reef systems are becoming more brittle, as a result of bleaching and disease. ARC Centre of Excellence Coral Reef Studies © http://www.coralcoe.org.au/

Being a bit fat may spell the difference between life and death if you’re a coral facing a bleaching crisis.

With the world’s coral reefs facing bleaching almost every year by the middle of the century as the oceans warm, a team of international scientists has revealed for the first time how corals can survive or perish in the face of the climatic onslaught.


An international team led by Dr Ken Anthony of the ACR Centre of Excellence for Coral Reef Studies and The University of Queensland has devised a world-first technique for assessing the chances of corals surviving a bleaching crisis.

Bleaching is caused when warm water circulates over the reef, causing the corals to shed the symbiotic algae they normally rely on for energy. If they cannot recover their algae in time, the corals starve to death.

'It mostly comes down to how well-fed the corals are before the bleaching event strikes,' Dr Anthony says. 'If they have high levels of lipids – or fats – in their system, it gives them the energy to hang on until they can re-establish their symbiotic relationship.'

The new technique offers scientists and reef managers a much clearer understanding of the processes that can lead to high mortality rates among corals affected by bleaching – and also an explanation for why some reefs appear to bounce back quickly, while others never recover.

The main factor is the amount of energy stored as fats in the coral’s tissues, Dr Anthony says. This in turn depends on the level of the food supply in the water prior to the bleaching event, how recently the corals spawned and whether or not there have been other disturbances – such as human activities, storms, low tides and competition from weeds.

After the bleaching event itself, coral survival may also depend on the amount of plankton available in the surrounding water which the corals can subsist on until they can recover their algal partners. 'We believe corals on coastal reefs are generally better able to recover from devastating bleaching event because there is often enough food in the water to keep them going', explains Prof Andrea Grottoli, a coral physiology expert from Ohio State University.

'The research shows clearly that malnourished corals with little or no plankton in the water to rely on have a higher mortality risk – whereas those which are fat before the event and have plenty of food around afterwards have a higher chance of survival', says Dr Mia Hoogenboom – who co-developed the mathematical models.

'Current predictions for global warming indicate that by mid-century ocean temperatures will have risen sufficiently to ensure most of the world’s coral reefs will face the threat of bleaching virtually every year. This tool we have developed helps us to understand much more clearly the chances corals have of surviving such events,' Dr Anthony explains.

'The risk is that annual bleaching will so weaken corals that they will not be able to cope, and will die out completely', says Rachel Middlebrook, a CoE PhD student specializing in coral bleaching stress.

The research also raises interesting questions, like whether there are steps which reef managers or tourism operators may be able to take to protect small areas of reef of particular significance – by providing ‘food aid’ to the local corals before and after bleaching events.

'You’d need to breed large quantities of plankton – as the prawn farming industry already does this. You’d also need to be sure the plankton could be released in a way that would benefit the corals, and the activity would not encourage weed growth.'

However, he adds, this is ‘a bit like rearranging the deckchairs on the Titanic in the hope of preventing the ship from sinking’. The over-riding need is to prevent the climate from warming uncontrollably.

Jeffrey Maynard, a reef ecologist and climate researcher from Melbourne University, said that, fortunately, predictions that 2009 could be a major bleaching year on the Great Barrier Reef never came true as temperatures throughout much of the Marine Park failed to exceed long-term averages for long enough to cause severe bleaching.

The paper describing the research, Energetics approach to predicting mortality risk from environmental stress: a case study of coral bleaching appears in the journal Functional Ecology and was written by Ken Anthony and Rachel Middlebrook (CoECRS and UQ), Mia Hoogenboom (Centre Scientifique de Monaco), Jeffrey Maynard (University of Melbourne) and Andrea Grottoli (Ohio State University).

http://www.coralcoe.org.au

Wildwind 2016 660x82InSunSport - NZNewport Boat Show 2016 660x82

Related Articles

America's Cup - Oracle Team USA's AC50 well underway in Warkworth
Oracle Team USA’s new America’s Cup Class boat is taking shape at the team’s build facility in New Zealand Oracle Team USA’s new America’s Cup Class boat is taking shape at the team’s build facility in New Zealand, Core Builders Composites, Warkworth, 40 minutes north of Auckland. The major components for the 15-meter platform, including the hulls and cross beams, have now been built.
Posted today at 1:12 am
America's Cup - Oracle Team USA play catch up with Softbank Team Japan
Back in April 2017, Softbank Team Japan mastered the foiling tack in their AC45 Surrogate boats Back in April 2017, Softbank Team Japan mastered the foiling tack in their AC45 Surrogate boats, claiming to be the first AC team to have achieved the move. Two days later Oracle Team USA claimed to have done the same.
Posted today at 12:45 am
Clipper Round the World Yacht Race - Crew catch up - Meet Dhruv Boruah
After crew members have completed their global ocean adventure, some go back to their previous lives and occupations After crew members have completed their global ocean adventure, some go back to their previous lives and occupations, some decide on a future in the marine industry, some take time out to assess their next move in life and others seek their next challenge.
Posted on 27 Aug
SoftBank Team Japan achieve first foiling tack
SoftBank Team Japan announced today that they cracked foiling tack earlier this year while training with their AC45 boat SoftBank Team Japan announced today that they cracked the foiling tack earlier this year while training with their AC45 Sport test boat in Bermuda.
Posted on 26 Aug
The Clipper Race turns 20!
Throughout the race, tales of crew celebrating birthdays on board filter back and they are always a special occasion Throughout the race, tales of Clipper Race crew celebrating their birthdays on board filter back and they are always a special occasion, likely to remain a completely unique event in their lifetime.
Posted on 23 Aug
America's Cup - Architect of NZ Qualifier withdrawal steps down
The Commissioner for the America's Cup General Dr. Harvey Schiller has stepped down from the role The Commissioner for the America's Cup General Dr. Harvey Schiller has stepped down from the role and will finish at the end of the month. The move was confirmed today by America's Cup correspondent Bernie Wilson of the Associated Press.
Posted on 23 Aug
An Q&A with Steve and Heidi Benjamin about the NYYC’s 2016 Queen’s Cup
Sail-World caught up with Steve and Heidi Benjamin to learn more about Heidi’s historic win in the NYYC’s Queen’s Cup. When it comes to U.S. Grand Prix sailing, it’s hard not to encounter the names of Steve and Heidi Benjamin. The two highly polished sailors have been successfully campaigning their series of yachts, named SPOOKIE, for years, starting first with a Carkeek 40 and progressing to their TP52. I caught up with Steve and Heidi to learn more about Heidi’s historic win in the NYYC’s Queen’s Cup
Posted on 19 Aug
PredictWind - One stop shop
PredictWind have taken the bold step of adding government provided forecasts to their award winning forecasting software PredictWind the world leader in forecasting believe that more is better, and have taken the bold step of adding government provided forecasts to their award winning forecasting software.
Posted on 15 Aug
Rio 2016 - Fresher breezes expected inside and outside on Day 3
Stronger winds are expected for the third day of racing in the 2016 Olympic Sailing Regatta in Rio de Janeiro. Stronger winds are expected for the third day of racing in the 2016 Olympic Sailing Regatta in Rio de Janeiro. Two of the fleet scheduled to race outside on the Atlantic Ocean course off Copacabana Beach, while the 470 Men and Women will race inside on Guananara Bay.
Posted on 10 Aug
35 Copa del Rey Mapfre - Armin Strom Sailing Team in action
Armin Strom Sailing Team remain in contention for the top of the podium throughout the 35 Copa del Rey Mapfre this week. Heading the leaderboard from the start and quickly finding a ‘turbo’ foiling mode saw Armin Strom Sailing Team remain in contention for the top of the podium throughout the 35 Copa del Rey Mapfre this week.
Posted on 8 Aug