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-TWnltlfrdehiiditjakomsfaptruesswsvthtrurvi

EVIDENCE

How Solar Heat Drives Rapid Melting Of Parts Of Antarctica's Largest Ice Shelf
How Solar Heat Drives Rapid Melting Of Parts Of Antarctica's Largest Ice Shelf
by Craig Stewart
The ocean that surrounds Antarctica plays a crucial role in regulating the mass balance of the continent’s ice cover.
The Arctic Paradox
by Tobias Thorleifsson
Explore Ellesmere Island with Tobias in this talk, as he urges us to protect this arctic environment from the hands of…
7 Surprising Results From The Reduction Of Arctic Sea Ice Cover
by David Barber
It is now well known that sea ice in the Arctic has changed in both extent and thickness over the past several decades.
Anchorage Hits 90 Degrees for First Time in Recorded History
Anchorage Hits 90 Degrees for First Time in Recorded History
by Jake Johnson
"This is unprecedented. I tease people that Anchorage is the coolest city in the country—and climatically that is…
Game On Climate Change Game On
by Laura Tenenbaum
Laura Faye Tenenbaum is the Senior Science Editor for the NASA’s Global Climate Change publication and a member of the…
After Data Shows Last Month Was Hottest June on Record, Sanders Says Maybe Now Is 'Time to Start Treating This Like a Crisis and Not a Hoax'
After Data Shows Last Month Was Hottest June on Record, Sanders Says Maybe Now Is 'Time to Start Treating This Like a Crisis and Not a Hoax'
by Jon Queall
"It's only the hottest June ever recorded on planet earth," said 350.org co-founder Bill McKibben with sarcasm. "So,…
Edge of the Great Dying: Extinction crisis
by Stop Fossil Fuels
At least a million forms of life hover at the edge of extinction as humans take over the world. Lead author Sandra Diaz…
Scientists Have Been Drilling Into The Ocean Floor For 50 Years – Here's What They've Found So Far
Scientists Have Been Drilling Into The Ocean Floor For 50 Years – Here's What They've Found So Far
by Suzanne O'Connell
It’s stunning but true that we know more about the surface of the moon than about the Earth’s ocean floor.

LATEST VIDEOS

5 Ways To Be A Responsible Wildlife Tourist
5 Ways To Be A Responsible Wildlife Tourist
by Tracie McKinney
Imagine walking through a lush tropical forest. You hear a rustle overhead, and a half-eaten fruit plops onto the…
Climate Change Is Affecting Crop Yields And Reducing Global Food Supplies
Climate Change Is Affecting Crop Yields And Reducing Global Food Supplies
by Deepak Ray
Farmers are used to dealing with weather, but climate change is making it harder by altering temperature and rainfall…
The Arctic Paradox
by Tobias Thorleifsson
Explore Ellesmere Island with Tobias in this talk, as he urges us to protect this arctic environment from the hands of…
Increased Drought Amid Climate Change & Warming
by Kate Marvel, Radio Ecoshock
Columbia/NASA scientist Kate Marvel explains “hyroclimate” as rains and droughts go extreme. When it comes to your…
7 Surprising Results From The Reduction Of Arctic Sea Ice Cover
by David Barber
It is now well known that sea ice in the Arctic has changed in both extent and thickness over the past several decades.
Half-Submerged Trump Head, Says Artist, Designed to Silence Destructive Words and Deeds of US President
Half-Submerged Trump Head, Says Artist, Designed to Silence Destructive Words and Deeds of US President
by Eoin Higgins
"The idea was to gag Trump, to silence him, but he continues to speak."
'The Climate Crisis Doesn't Go on Summer Holiday, And Neither Will We,' Says Greta Thunberg as #FridaysForFuture Returns to the Streets
The Climate Crisis Doesn't Go on Summer Holiday, And Neither Will We, Says Greta Thunberg as #FridaysForFuture Returns to the Streets
by Jessica Corbett
A campaigner in Nigeria adds, "It doesn't matter the course you study nor your age, we need you to join climate…
Anchorage Hits 90 Degrees for First Time in Recorded History
Anchorage Hits 90 Degrees for First Time in Recorded History
by Jake Johnson
"This is unprecedented. I tease people that Anchorage is the coolest city in the country—and climatically that is…

LATEST ARTICLES

It's Time To Wake Up To The Devastating Impact Flying Has On The Environment
It's Time To Wake Up To The Devastating Impact Flying Has On The Environment
by Roger Tyers
While in many countries new cars, domestic appliances, and even houses now have mandatory energy efficiency…
5 Ways To Be A Responsible Wildlife Tourist
5 Ways To Be A Responsible Wildlife Tourist
by Tracie McKinney
Imagine walking through a lush tropical forest. You hear a rustle overhead, and a half-eaten fruit plops onto the…
What Does The Dutch Court Ruling On Climate Targets Mean For Australia?
What Does The Dutch Court Ruling On Climate Targets Mean For Australia?
by Katherine Lake
In a landmark ruling, The Hague District Court has ordered the Netherlands government to take more action to reduce its…
How Solar Heat Drives Rapid Melting Of Parts Of Antarctica's Largest Ice Shelf
How Solar Heat Drives Rapid Melting Of Parts Of Antarctica's Largest Ice Shelf
by Craig Stewart
The ocean that surrounds Antarctica plays a crucial role in regulating the mass balance of the continent’s ice cover.
How China’s Sponge Cities Aim To Re-use 70% Of Rainwater
How China’s Sponge Cities Aim To Re-use 70% Of Rainwater
by Asit K. Biswas and Kris Hartley
Asian cities are struggling to accommodate rapid urban migration, and development is encroaching on flood-prone areas.
Aviation Emissions Are Rising – And Industry Solutions Are Just Technological Myths
by Paul Peeters, et al
Imagine you are the government’s Minister for Transport: the economy is prospering, global oil prices are falling, and…
With Climate Change Likely To Sharpen Conflict, NZ Balances Pacifist Traditions With Defence Spending
by David Belgrave
In most countries, the question of whether to produce guns or butter is a metaphor for whether a country should put its…
Climate Change Is Putting Even Resilient And Adaptable Animals Like Baboons At Risk
by Isabelle Catherine Winder
Baboons are large, smart, ground-dwelling monkeys. They are found across sub-Saharan Africa in various habitats and eat…