Bleaching Has Struck The Southernmost Coral Reef In The World

Bleaching Has Struck The Southernmost Coral Reef In The World

This month corals in Lord Howe Island Marine Park began showing signs of bleaching. The 145,000 hectare marine park contains the most southerly coral reef in the world, in one of the most isolated ecosystems on the planet.

Following early reports of bleaching in the area, researchers from three Australian universities and two government agencies have worked together throughout March to investigate and document the bleaching.

Sustained heat stress has seen 90% of some reefs bleached, although other parts of the marine park have escaped largely unscathed.

Bleaching is uneven

Lord Howe Island was named a UNESCO World Heritage site in 1982. It is the coral reef closest to a pole, and contains many species found nowhere else in the world.

Bleaching Has Struck The Southernmost Coral Reef In The World Coral bleaching observed at Lord Howe in March 2019. Author provided

Two of us (Tess Moriarty and Rosie Steinberg) have surveyed reefs across Lord Howe Island Marine Park to determine the extent of bleaching in the populations of hard coral, soft coral, and anemones. This research found severe bleaching on the inshore lagoon reefs, where up to 95% of corals are showing signs of extensive bleaching.

However, bleaching is highly variable across Lord Howe Island. Some areas within the Lord Howe Island lagoon coral reef are not showing signs of bleaching and have remained healthy and vibrant throughout the summer. There are also corals on the outer reef and at deeper reef sites that have remained healthy, with minimal or no bleaching.

One surveyed reef location in Lord Howe Island Marine Park is severely impacted, with more than 90% of corals bleached; at the next most affected reef site roughly 50% of corals are bleached, and the remaining sites are less than 30% bleached. At least three sites have less than 5% bleached corals.

Bleaching Has Struck The Southernmost Coral Reef In The World Healthy coral photographed at Lord Howe marine park in March 2019. Author provided

Over the past week heat stress has continued in this area, and return visits to these sites revealed that the coral condition has worsened. There is evidence that some corals are now dying on the most severely affected reefs.

Forecasts for the coming week indicate that water temperatures are likely to cool below the bleaching threshold, which will hopefully provide timely relief for corals in this valuable reef ecosystem. In the coming days, weeks and months we will continue to monitor the affected reefs and determine the impact of this event to the reef system, and investigate coral recovery.

What’s causing the bleaching?

The bleaching was caused by high seawater temperature from a persistent summer marine heatwave off southeastern Australia. Temperature in January was a full degree Celsius warmer than usual, and from the end of January to mid-February temperatures remained above the local bleaching threshold.

Sustained heat stressed the Lord Howe Island reefs, and put them at risk. They had a temporary reprieve with cooler temperatures in late February, but by March another increase put the ocean temperature well above safe levels. This is now the third recorded bleaching event to have occurred on this remote reef system.

Bleaching Has Struck The Southernmost Coral Reef In The World Satellite monitoring of sea-surface temperature (SST) revealed three periods in excess of the Bleaching Threshold during which heat stress accumulated (measured as Degree Heating Weeks, DHW). Since January 2019, SST (purple) exceeded expected monthly average values (blue +) by as much as 2°C. The grey line and envelope indicate the predicted range of SST in the near future. Source: NOAA Coral Reef Watch

However, this heatwave has not equally affected the whole reef system. In parts of the lagoon areas the water can be cooler, due to factors like ocean currents and fresh groundwater intrusion, protecting some areas from bleaching. Some coral varieties are also more heat-resistant, and a particular reef that has been exposed to high temperatures in the past may better cope with the current conditions. For a complex variety of reasons, the bleaching is unevenly affecting the whole marine park.

Coral bleaching is the greatest threat to the sustainability of coral reefs worldwide and is now clearly one of the greatest challenges we face in responding to the impact of global climate change. UNESCO World Heritage regions, such as the Lord Howe Island Group, require urgent action to address the cause and impact of a changing climate, coupled with continued management to ensure these systems remain intact for future generations.

About The Authors

Tess Moriarty, Phd candidate, University of Newcastle; Bill Leggat, Associate professor, University of Newcastle; C. Mark Eakin, Coordinator, Coral Reef Watch, National Oceanic and Atmospheric Administration; Rosie Steinberg, PhD Student, UNSW; Scott Heron, Senior Lecturer, James Cook University, and Tracy Ainsworth, Associate professor, UNSW

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Related Books

Climate Change: What Everyone Needs to Know

by Joseph Romm
0190866101The essential primer on what will be the defining issue of our time, Climate Change: What Everyone Needs to Know® is a clear-eyed overview of the science, conflicts, and implications of our warming planet. From Joseph Romm, Chief Science Advisor for National Geographic's Years of Living Dangerously series and one of Rolling Stone's "100 people who are changing America," Climate Change offers user-friendly, scientifically rigorous answers to the most difficult (and commonly politicized) questions surrounding what climatologist Lonnie Thompson has deemed "a clear and present danger to civilization.". Available On Amazon

Climate Change: The Science of Global Warming and Our Energy Future second edition Edition

by Jason Smerdon
0231172834This second edition of Climate Change is an accessible and comprehensive guide to the science behind global warming. Exquisitely illustrated, the text is geared toward students at a variety of levels. Edmond A. Mathez and Jason E. Smerdon provide a broad, informative introduction to the science that underlies our understanding of the climate system and the effects of human activity on the warming of our planet.Mathez and Smerdon describe the roles that the atmosphere and ocean play in our climate, introduce the concept of radiation balance, and explain climate changes that occurred in the past. They also detail the human activities that influence the climate, such as greenhouse gas and aerosol emissions and deforestation, as well as the effects of natural phenomena.  Available On Amazon

The Science of Climate Change: A Hands-On Course

by Blair Lee, Alina Bachmann
194747300XThe Science of Climate Change: A Hands-On Course uses text and eighteen hands-on activities to explain and teach the science of global warming and climate change, how humans are responsible, and what can be done to slow or stop the rate of global warming and climate change. This book is a complete, comprehensive guide to an essential environmental topic. Subjects covered in this book include: how molecules transfer energy from the sun to warm the atmosphere, greenhouse gases, the greenhouse effect, global warming, the Industrial Revolution, the combustion reaction, feedback loops, the relationship between weather and climate, climate change, carbon sinks, extinction, carbon footprint, recycling, and alternative energy. Available On Amazon

From The Publisher:
Purchases on Amazon go to defray the cost of bringing you InnerSelf.comelf.com, MightyNatural.com, and ClimateImpactNews.com at no cost and without advertisers that track your browsing habits. Even if you click on a link but don't buy these selected products, anything else you buy in that same visit on Amazon pays us a small commission. There is no additional cost to you, so please contribute to the effort. You can also use this link to use to Amazon at any time so you can help support our efforts.

 

enafarzh-CNzh-TWdanltlfifrdeiwhihuiditjakomsnofaplptruesswsvthtrukurvi

follow InnerSelf on

facebook-icontwitter-iconrss-icon

 Get The Latest By Email

{emailcloak=off}

EVIDENCE

PBS Nova's Polar Extremes
PBS Nova's Polar Extremes
by PBS
In this two-hour special, renowned paleontologist Kirk Johnson takes us on an epic adventure through time at the polar…
Climate Research Struggles To Find Funding
Climate Research Struggles To Find Funding
by Kieran Cooke
Climate research is the poor relation of the academic world. Since 1990 it’s won less than 5% of the research funds…
Atlantic Current Could Falter Before 2100
Atlantic Current Could Falter Before 2100
by Tim Radford
v The Atlantic current won’t come to a full stop the day after tomorrow. But it could face a temporary halt later this…
Temperature in Antarctica Soars Past 69°F as NOAA Reports Last Month Was World's Hottest January on Record
Temperature in Antarctica Soars Past 69°F as NOAA Reports Last Month Was World's Hottest January on Record
by Jessica Corbett
While the reading in Antarctica still needs to be confirmed, the Brazilian scientists who logged it called the new…
CO₂ Levels And Climate Change: Is There Really A Controversy?
CO₂ Levels And Climate Change: Is There Really A Controversy?
by Guillaume Paris and Pierre-Henri Blard
The relationship between atmospheric CO2 levels and climate change is often perceived as a controversial subject.
Ancient Antarctic Ice Melt Caused Extreme Sea Level Rise 129,000 Years Ago – And It Could Happen Again
Ancient Antarctic Ice Melt Caused Extreme Sea Level Rise 129,000 Years Ago – And It Could Happen Again
by Chris Fogwill, et al
Our new research might be able to provide some insight into what effect a warmer world would have in Antarctica, by…
3 Things Historical Literature Can Teach Us About The Climate Crisis
3 Things Historical Literature Can Teach Us About The Climate Crisis
by David Higgins and Tess Somervell
New novels about climate change – climate fiction, or cli-fi – are being published all the time. The nature of the…
Antarctica Has Lost Nearly 3 Trillion Tonnes Of Ice Since 1992
Antarctica Has Lost Nearly 3 Trillion Tonnes Of Ice Since 1992
by Thomas Slater and Andrew Shepherd
It can be easy to overlook the monstrous scale of the Antarctic ice sheet. Ice, thick enough in many places to bury…

LATEST VIDEOS

PBS Nova's Polar Extremes
PBS Nova's Polar Extremes
by PBS
In this two-hour special, renowned paleontologist Kirk Johnson takes us on an epic adventure through time at the polar…
A huge iceberg just broke off West Antarctica’s most endangered glacier
A Huge Iceberg Just Broke Off West Antarctica’s Most Endangered Glacier
by Madeleine Stone
Huge blocks of ice regularly shear away from Antarctica’s ice shelves, but the losses are speeding up.
The Rise Of Solar Power
by CNBC
Solar power is on the rise. You can see the evidence on rooftops and in the desert, where utility-scale solar plants…
World's Largest Batteries: Pumped Storage
by Practical Engineering
The vast majority of our grid-scale storage of electricity uses this clever method.
Hydrogen Fuels Rockets, But What About Power For Daily Life?
Hydrogen Fuels Rockets, But What About Power For Daily Life?
by Zhenguo Huang
Have you ever watched a space shuttle launch? The fuel used to thrust these enormous structures away from Earth’s…
Fossil Fuel Production Plans Could Push Earth off a Climate Cliff
by The Real News Network
The United Nations is beginning its climate summit in Madrid.
Big Rail Spends More on Denying Climate Change than Big Oil
by The Real News Network
A new study concludes that rail is the industry that's injected the most money into climate change denial propaganda…
Did Scientists Get Climate Change Wrong?
by Sabine Hossenfelder
Interview with Prof Tim Palmer from the University of Oxford.

LATEST ARTICLES

Natural Flood Management Would Be Overwhelmed By Britain's Winter Super-floods
Natural Flood Management Would Be Overwhelmed By Britain's Winter Super-floods
by Robert Wilby and Simon Dadson
As large swathes of the UK endure the worst floods in living memory, hearts and minds are rightly focused on protecting…
Keeping The City Cool Isn't Just About Tree Cover – It Calls For A Commons-based Climate Response
Keeping The City Cool Isn't Just About Tree Cover – It Calls For A Commons-based Climate Response
by Abby Mellick Lopes and Cameron Tonkinwise
A recent report by the Greater Sydney Commission singles out urban heat as one of four priority areas given our coming…
Low Flammability Plants Could Help Our Homes Survive Bushfires
Low Flammability Plants Could Help Our Homes Survive Wildfires
by Tim Curran, et al
Destructive wildfires are becoming more common in many parts of the world and are predicted to worsen with climate…
Carbon Pricing May Be Overrated, If History Is Any Indication
Carbon Pricing May Be Overrated, If History Is Any Indication
by Cameron Roberts
A common demand in discussions about climate change is to respect the science. This is appropriate. We should all be…
Here Are 5 Practical Ways Trees Can Help Us Survive Climate Change
Here Are 5 Practical Ways Trees Can Help Us Survive Climate Change
by Gregory Moore
As the brutal reality of climate change dawned this summer, you may have asked yourself a hard question: am I…
A Military Perspective On Climate Change Could Bridge The Gap Between Believers And Doubters
A Military Perspective On Climate Change Could Bridge The Gap Between Believers And Doubters
by Michael Klare
As experts warn that the world is running out of time to head off severe climate change, discussions of what the U.S.…
Nearly 80% Of Australians Affected In Some Way By The Bushfires, New Survey Shows
Nearly 80% Of Australians Affected In Some Way By The Bushfires, New Survey Shows
by Nicholas Biddle, et al
Our research shows the vast majority of Australians were touched in some way by the fires. We asked about eight…
Changing Climate Has Stalled Australian Wheat Yields
Changing Climate Has Stalled Australian Wheat Yields
by Zvi Hochman; David L. Gobbett, and Heidi Horan, CSIRO
Australia’s wheat yields more than trebled during the first 90 years of the 20th century but have stalled since 1990.…