I Studied What Happens To Reef Fish After Coral Bleaching. What I Saw Still Makes Me Nauseous

I Studied What Happens To Reef Fish After Coral Bleaching. What I Saw Still Makes Me Nauseous Victor Huertas, Author provided Jodie L. Rummer

The Great Barrier Reef is suffering its third mass bleaching event in five years. It follows the record-breaking mass bleaching event in 2016 that killed a third of Great Barrier Reef corals, immediately followed by another in 2017.

While we don’t know if fish populations declined from the 2016 bleaching disaster, one 2018 study did show the types of fish species on some coral reefs changed. Our study dug deeper into fish DNA.

I was part of an international team of scientists that, for the first time, tracked wild populations of five species of coral reef fish before, during, and after the 2016 marine heatwave.

From a scientific perspective, the results are fascinating and world-first.

I Studied What Happens To Reef Fish After Coral Bleaching. What I Saw Still Makes Me Nauseous Marine heatwaves are now becoming more frequent and more severe with climate change. Corals are bleaching, as pictured here. Jodie Rummer, Author provided

We used gene expression as a tool to survey how well fish can handle hotter waters. Gene expression is the process where a gene is read by cell machinery and creates a product such as a protein, resulting in a physical trait.

We know many tropical coral reef fish are already living at temperatures close to their upper limits. Our findings can help predict which of these species will be most at risk from repeated heatwaves.

But from a personal perspective, I still feel nauseous thinking about what the reef looked like during this project. I’ll probably feel this way for a long time.

Rewind to November 2015

We were prepared. Back then we didn’t know the reef was about to bleach and lead to widespread ecological devastation. But we did anticipate that 2016 would be an El Niño year. This is a natural climate cycle that would mean warm summer waters in early 2016 would stick around longer than usual.

But we can’t blame El Niño – the ocean has already warmed by 1°C above pre-industrial levels from continued greenhouse gas emissions. What’s more, marine heatwaves are becoming more frequent and severe with climate change.

Given this foresight, we took some quick liver biopsies from several coral reef fish species at our field site in December 2015, just in case.

I Studied What Happens To Reef Fish After Coral Bleaching. What I Saw Still Makes Me Nauseous Coral bleaching at Magnetic Island, March 2020. Victor Huertas, Author provided

A couple months later, we were literally in hot water

In February 2016, my colleague and I were based on Lizard Island in the northern part of the Great Barrier Reef working on another project.

The low tides had shifted to the afternoon hours. We were collecting fish in the shallow lagoon off the research station, and our dive computers read that the water temperature was 33°C.

We looked at each other. These are the temperatures we use to simulate climate change in our laboratory studies for the year 2050 or 2100, but they’re happening now.

Over the following week, we watched corals turn fluorescent and then bone-white.

The water was murky with slime from the corals’ immune responses and because they were slowly exuding their symbiotic zooxanthellae – the algae that provides corals with food and the vibrant colours we know and love when we think about a coral reef. The reef was literally dying before our eyes.

I Studied What Happens To Reef Fish After Coral Bleaching. What I Saw Still Makes Me Nauseous A third of the corals on the Great Barrier Reef perished after the 2016 heatwave. Jodie Rummer, Author provided

Traits for dealing with heatwaves

We sampled fish during four time periods around this devastating event: before, at the start, during, and after.

Some genes are always “switched on”, regardless of environmental conditions. Other genes switch on or off as needed, depending on the environment.

If we found these fish couldn’t regulate their gene expression in response to temperature stress, then the functions – such as metabolism, respiration, and immune function – also cannot change as needed. Over time, this could compromise survival.

The plasticity (a bit like flexibility) of these functions, or phenotypes, is what buffers an organism from environmental change. And right now, this may be the only hope for maintaining the health of coral reef ecosystems in the face of repeated heatwave events.

So, what were the fish doing?

We looked at expression patterns of thousands of genes. We found the same genes responded differently between species. In other words, some fish struggled more than others to cope with marine heatwaves.

I Studied What Happens To Reef Fish After Coral Bleaching. What I Saw Still Makes Me Nauseous Ostorhinchus doederleini, a species of cardinalfish, is bad at coping with marine heatwaves. Göran Nilsson, Author provided

The species that coped the least was a nocturnal cardinalfish species (Cheilodipterus quinquelineatus). We found it had the lowest number of differentially expressed genes (genes that can switch on or off to handle different stressors), even when facing the substantial change in conditions from the hottest to the coolest months.

In contrast, the spiny damselfish (Acanthochromis polyacanthus) responded to the warmer conditions with changes in the expression of thousands of genes, suggesting it was making the most changes to cope with the heatwave conditions.

What can these data tell us?

Our findings not only have implications for specific fish species, but for the whole ecosystem. So policymakers and the fishing industry should screen more species to predict which will be sensitive and which will tolerate warming waters and heatwaves. This is not a “one size fits all” situation.

I Studied What Happens To Reef Fish After Coral Bleaching. What I Saw Still Makes Me Nauseous One of the species that showed the least amount of change under warming was Cheilodipterus quinquelineatus. Moises Antonio Bernal de Leon, Author provided

Fish have been on the planet for more than 400 million years. Over time , they may adapt to rising temperatures or migrate to cooler waters.

But, the three recent mass bleaching events is unprecedented in human history, and fish won’t have time to adapt.

My drive to protect the oceans began when I was a child. Now it’s my career. Despite the progress my colleagues and I have made, my nauseous feelings remain, knowing our science alone may not be enough to save the reef.

The future of the planet, the oceans, and the Great Barrier Reef lies in our collective actions to reduce global warming. What we do today will determine what the Great Barrier Reef looks like tomorrow.The Conversation

About The Author

Jodie L. Rummer, Associate Professor & Principal Research Fellow, James Cook University

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

Related Books

Life After Carbon: The Next Global Transformation of Cities

by Peter Plastrik , John Cleveland
1610918495The future of our cities is not what it used to be. The modern-city model that took hold globally in the twentieth century has outlived its usefulness. It cannot solve the problems it helped to create—especially global warming. Fortunately, a new model for urban development is emerging in cities to aggressively tackle the realities of climate change. It transforms the way cities design and use physical space, generate economic wealth, consume and dispose of resources, exploit and sustain the natural ecosystems, and prepare for the future. Available On Amazon

The Sixth Extinction: An Unnatural History

by Elizabeth Kolbert
1250062187Over the last half-billion years, there have been Five mass extinctions, when the diversity of life on earth suddenly and dramatically contracted. Scientists around the world are currently monitoring the sixth extinction, predicted to be the most devastating extinction event since the asteroid impact that wiped out the dinosaurs. This time around, the cataclysm is us. In prose that is at once frank, entertaining, and deeply informed, New Yorker writer Elizabeth Kolbert tells us why and how human beings have altered life on the planet in a way no species has before. Interweaving research in half a dozen disciplines, descriptions of the fascinating species that have already been lost, and the history of extinction as a concept, Kolbert provides a moving and comprehensive account of the disappearances occurring before our very eyes. She shows that the sixth extinction is likely to be mankind's most lasting legacy, compelling us to rethink the fundamental question of what it means to be human. Available On Amazon

Climate Wars: The Fight for Survival as the World Overheats

by Gwynne Dyer
1851687181Waves of climate refugees. Dozens of failed states. All-out war. From one of the world’s great geopolitical analysts comes a terrifying glimpse of the strategic realities of the near future, when climate change drives the world’s powers towards the cut-throat politics of survival. Prescient and unflinching, Climate Wars will be one of the most important books of the coming years. Read it and find out what we’re heading for. 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}

LATEST VIDEOS

Five Climate Disbeliefs: A Crash Course In Climate Misinformation
The Five Climate Disbeliefs: A Crash Course In Climate Misinformation
by John Cook
This video is a crash course in climate misinformation, summarizing the key arguments used to cast doubt on the reality…
The Arctic Hasn't Been This Warm For 3 Million Years and That Means Big Changes For The Planet
The Arctic Hasn't Been This Warm For 3 Million Years and That Means Big Changes For The Planet
by Julie Brigham-Grette and Steve Petsch
Every year, sea ice cover in the Arctic Ocean shrinks to a low point in mid-September. This year it measures just 1.44…
What Is A Hurricane Storm Surge and Why Is It So Dangerous?
What Is A Hurricane Storm Surge and Why Is It So Dangerous?
by Anthony C. Didlake Jr
As Hurricane Sally headed for the northern Gulf Coast on Tuesday, September 15, 2020, forecasters warned of a…
Ocean Warming Threatens Coral Reefs and Soon Could Make It Harder To Restore Them
Ocean Warming Threatens Coral Reefs and Soon Could Make It Harder To Restore Them
by Shawna Foo
Anyone who’s tending a garden right now knows what extreme heat can do to plants. Heat is also a concern for an…
Sunspots Do Affect Our Weather But Not As Much As Other Things
Sunspots Do Affect Our Weather But Not As Much As Other Things
by Robert McLachlan
Are we headed for a period with lower Solar activity, i.e. sunspots? How long will it last? What happens to our world…
Dirty Tricks Climate Scientists Faced In Three Decades Since First IPCC Report
Dirty Tricks Climate Scientists Faced In Three Decades Since First IPCC Report
by Marc Hudson
Thirty years ago, in a small Swedish city called Sundsvall, the Intergovernmental Panel on Climate Change (IPCC)…
Methane Emissions Hit Record Breaking Levels
Methane Emissions Hit Record Breaking Levels
by Josie Garthwaite
Global emissions of methane have reached the highest levels on record, research shows.
kelp forrest 7 12
How The Forests Of The World’s Oceans Contribute To Alleviating The Climate Crisis
by Emma Bryce
Researchers are looking to kelp for help storing carbon dioxide far beneath the surface of the sea.

LATEST ARTICLES

Creative Destruction: The Covid-19 Economic Crisis Is Accelerating the Demise of Fossil Fuels
Creative Destruction: The Covid-19 Economic Crisis Is Accelerating the Demise of Fossil Fuels
by Peter Newman
Creative destruction “is the essential fact about capitalism”, wrote the great Austrian economist Joseph Schumpeter in…
Global Emissions Are Down By An Unprecedented 7% — But Don’t Start Celebrating Just Yet
Global Emissions Are Down By An Unprecedented 7% — But Don’t Start Celebrating Just Yet
by Pep Canadell et al
Global emissions are expected to decline by about 7% in 2020 (or 2.4 billion tonnes of carbon dioxide) compared to 2019…
Decades of Unsustainable Water Use Has Dried Up Lakes and Caused Environmental Destruction
Decades of Unsustainable Water Use Has Dried Up Lakes and Caused Environmental Destruction in Iran
by Zahra Kalantari et al
Salt storms are an emerging threat for millions of people in north-western Iran, thanks to the catastrophe of Lake…
Climate Sceptic or Climate Denier? It's Not That Simple and Here's Why
Climate Sceptic or Climate Denier? It's Not That Simple and Here's Why
by Peter Ellerton
Climate change is now climate crisis and a climate sceptic now a climate denier, according to the recently updated…
The 2020 Atlantic Hurricane Season Was A Record-Breaker, and It's Raising More Concerns About Climate Change
The 2020 Atlantic Hurricane Season Was A Record-Breaker, and It's Raising More Concerns About Climate Change
by James H. Ruppert Jr. and Allison Wing
We’re looking back at a trail of broken records, and the storms may still not be over even though the season officially…
Why Climate Change Is Making Autumn Leaves Change Colour Earlier
Why Climate Change Is Making Autumn Leaves Change Colour Earlier
by Philip James
Temperature and day length were traditionally accepted as the main determinants of when leaves changed colour and fell,…
Take Caution: Winter Drownings May Increase As Ice Thins With Climate Change
Take Caution: Winter Drownings May Increase As Ice Thins With Climate Change
by Sapna Sharma
Every winter, the ice that forms on lakes, rivers and oceans, supports communities and culture. It provides…
There Are No Time-Travelling Climatologists: Why We Use Climate Models
There Are No Time-Travelling Climatologists: Why We Use Climate Models
by Sophie Lewis and Sarah Perkins-Kirkpatrick
The first climate models were built on fundamental laws of physics and chemistry and designed to study the climate…