Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017

Warming seawaters, caused by climate change and extreme climatic events, threaten the stability of tropical coral reefs, with potentially devastating implications for many reef species and the human communities that reefs support.

New research by the University of Exeter shows that increased surface ocean temperatures during the strong 2016 El Niño led to a major coral die-off event in the Maldives, and that this has caused reef growth rates to collapse. They also found that the rates at which some reefs species, in particular parrotfish, are eroding the reefs had increased following this coral die-off event.


Picture was taken in September 2016 along the shallow (2-3 m depth) fore-reef slope habitat around Kandahalagala showing the extent of coral bleaching-driven coral mortality that has preferentially impacted Acropora sp.

Credit: University of Exeter

Similar magnitudes of coral death have been reported on many other reefs in the region, including on the northern Great Barrier Reef, suggesting similar impacts may be very widespread.

Professor Chris Perry and Dr Kyle Morgan, of the University of Exeter's Geography department, studied the impact of the 2016 El Niño event at sites in the southern Maldives and found that the event had not only caused widespread coral bleaching, a phenomenon whereby corals expel their photosynthesising algae when stressed by high temperatures, but that this had also led to extensive coral death in all shallow water reef habitats examined.

"A very major concern now is how quickly these reefs might recover. Recovery from similar past disturbances in the Maldives have taken 10-15 years, but major bleaching events are predicted to become far more frequent than this. If this is the case it could lead to long-term loss of reef growth and so limit the coastal protection and habitat services these reefs presently provide," Professor Perry said.

"The most alarming aspect of this coral die-off event is that it has led to a rapid and very large decline in the growth rate of the reefs. This in turn has major implications not only for the capacity of these reefs to match any increases in sea-level, but is also likely to lead to a loss of the surface structure of the reefs that is so critical for supporting fish species diversity and abundance."

Coral reefs are formed by the accumulation of coral skeletons (made of calcium carbonate) that builds up over 100's to 1000's of years, forming the complex structures that support a huge diversity of marine life.

The so-called 'carbonate budget' of a reef, which represents the balance between the rate at which this carbonate is produced by corals and the rate at which it is removed (by biological or physical erosion or chemical dissolution), influences the development of these structures and how fast a reef can grow.

The effect these combined factors was a major decline in the carbonate budgets of these reefs, with an average reduction of 157%. Before the warming event, the reefs had been in a period of rapid growth, but after the period of higher sea temperatures a negative carbonate budget was recorded at all sites. Put simply, the structure of these reefs is now eroding at a faster rate that it is growing. Based on past studies the researchers suggest that given the severity of the bleaching impacts it may take 10 to 15 years for full recovery to occur.

The extent of the 2016 bleaching, which also affected reefs in other parts of the Indian Ocean and Pacific, was so severe that it was subsequently named the 'Third Global Coral Bleaching Event'.

Dr Kyle Morgan said: "Coral reefs provide a wealth of benefits. They are vital habitats, essential for a vast number of species and they are also important for tourism and food provision. The reduction in carbonate budget threatens these benefits and may well also lead to the structural collapse of reefs. The key issue to consider now is whether, and when, these reefs will recover, both ecologically and in terms of their growth. Based on past trajectories, we predict recovery will take at least a decade, however it all depends on the extent of future warming events and climate change."

University of Exeter scientists warned there could be further rises in sea temperatures owing to global warming with potentially devastating effects on coral reefs.

Professor Mat Collins, an expert in climate modelling at the University of Exeter, said:

"We expect El Niño variability to continue into the future which, when combined with rising temperatures due to global warming, means we will see unprecedented sea temperatures and increasing incidence of coral bleaching."

Bleaching drives collapse in reef carbonate budgets and reef growth potential on southern Maldives reefs is published in Scientific Reports.

###

Professor Perry is available on c.perry@exeter.ac.uk and Dr Kyle Morgan is available on k.morgan@exeter.ac.uk

Media Contact

Marie Woolf
m.woolf@exeter.ac.uk
07-824-545-608

 @uniofexeter

http://www.exeter.ac.uk 

Marie Woolf | EurekAlert!

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

A novel synthetic antibody enables conditional “protein knockdown” in vertebrates

20.08.2018 | Life Sciences

Metamolds: Molding a mold

20.08.2018 | Information Technology

It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

20.08.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>