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Studying ‘super corals’

‘Everything was white.’ Marine biologist Verena Schoepf describes the first time she saw a mass bleaching event of corals. The event did not just occur at her study site in Western Australia, but all around the world – the third documented global mass bleaching (2015-2016). ‘I saw the real impact when I came back six months later: much of the reef had died. And a year later, in the famous Great Barrier Reef, this happened again.’

Coral reefs around the world are under threat by a number of influences. There are natural dangers, like cyclones. But many major threats are human in origin. Think of pollution and overfishing. And then there’s climate change, which causes warming of the oceans and ocean acidification; both major causes of concern for these fragile ecosystems. Oceans are a well-known heat sink, absorbing a large part of the heat produced by CO2-driven global warming.

Schoepf explains: ‘Corals live in symbiosis with microscopic algae that provide them with most of their energy and nutrients through photosynthesis. Heatwaves associated with ocean warming lead to the breakdown of this symbiosis. Under influence of heat corals expel the symbiotic algae living inside their tissue. Without them, the corals not only lose their colour – turning white or ‘bleached’ - but are also deprived of their primary source of energy.

If the heat stress lasts for too long, the corals will starve and die.’ At the same time, part of the excess CO2 in the atmosphere dissolves in the oceans, making the water more acidic. This increase in seawater acidity makes it more difficult for corals to build their skeletons and therefore to build reefs.

Verena Schoepf
Verena Schoepf

Schoepf’s fascination for ocean life started with seeing nature documentaries on tv in her native Austria while she was still a child. ‘I got inspired by the documentaries of the underwater pioneer Hans Hass, who is the Jacques-Yves Cousteau of Austria,’ recalls Schoepf.

‘His documentaries inspired me to snorkel in the Mediterranean Sea for hours. When I was twelve I saw coral reefs for the first time. There, in the Red Sea, I knew that coral reefs were the marine ecosystems that I was most interested in. I was absolutely mesmerised by the diversity of colours, forms and shapes. Coral reefs are biodiversity hotspots and essentially bustling underwater cities. You could compare them to a city like New York, there is so much going on in so many dimensions.’

Acidification versus heat stress

After studying Biology at the University of Innsbruck in Austria, Schoepf moved to the United States for a PhD at Ohio State University. There she studied how reef-building corals are impacted by multiple climate change stressors: acidification and repeated bleaching events. She investigated four different species of coral in a simulated environment in the lab.

Schoepf found that the coral species she studied were more resistant to acidification than expected. ‘These species also didn’t consume their energy reserves in order to maintain calcification rates, so that was good news! It highlights that ocean warming is a much bigger threat to coral reefs than acidification,’ she comments.  

But, she did find that consecutive bleaching events took their toll, albeit differently in different species. Schoepf: ‘One of the species I studied was quite resistant to the first heat stress event, but then became increasingly susceptible to the second one a year later. A second coral species showed the opposite pattern.

This challenged the traditional view that we can easily predict the winners and losers of coral bleaching, because higher stress frequency dramatically changes coral stress tolerance. Back then there were almost no reefs that had bleached two years in a row. So we didn’t expect this to happen on a larger scale until 2030 or 2050. But within five years after completing my PhD, this already became a widespread reality. For example, the Great Barrier Reef experienced back-to-back bleaching for the first time in 2016 and 2017.’

Extreme environment

After her PhD, Schoepf continued her research career as a postdoc and later on research programme co-leader – the youngest ever – at the ARC Centre of Excellence for Coral Reef Studies at The University of Western Australia in Perth. There, she studied reefs in the Kimberley region, which is a naturally extreme environment for corals due to the world’s largest tropical tides (up to 10 metres tidal range). Schoepf became fascinated with corals in this region, that she sometimes refers to as ‘super corals’.

Schoepf: ‘These corals are able to survive in shallow pools, that can heat up to temperatures that would kill most other corals, making them ideal organisms to study for a better understanding of how corals can cope with warming oceans. The conditions there were not just hard for the corals, but also for us as researchers. It is very hot and humid up there. There are saltwater crocodiles, deadly jellyfish and snakes.

If something happens, the nearest hospital is three hours away by four-wheel drive. I had to walk on the reefs at low tide. You don’t want to swim or dive there, since there are also very healthy shark populations. This was next-level fieldwork; challenging, but also very rewarding.’

Ever since, Schoepf’s focus has been on gaining a better understanding of the mechanisms that increase the resistance of corals to warming and acidifying oceans. Her main message though, is not to think of ‘super corals’ as a solution to all problems that coral reefs face today.

Schoepf: ‘This is such a new field, there is so much we don’t know yet. How long has it taken these corals to develop this resilience?  Will they maintain this resilience if you put them in a slightly different environment? And are they any trade-offs? We don’t know yet.’ And even though the super corals are more resilient, they are not completely immune to heat stress.

The corals at her Kimberley site, for instance, did experience bleaching in 2016. ‘The good news is that they also recovered much faster, at least this time. That gives reason for hope’, says Schoepf. ‘However, we really need to accept that there is no safe place for corals as the oceans continue to warm – if we want our children to be able to see healthy coral reefs, we urgently need to reduce greenhouse gas emissions.’

MacGillavry Fellowship

In November 2019, Schoepf joined the Institute for Biodiversity and Ecosystem Dynamics at the University of Amsterdam as a MacGillavry fellow. After having studied coral reefs in Australia, Mexico and the Red Sea, she will now switch her focus to the Dutch Caribbean. Yes, there are potential super corals there too. For instance in the shallow inland bays on Curaçao, where corals are not only subject to heat stress but also to several other stressors.

Schoepf says she was excited to join the UvA: ‘There is a strong tradition of coral reef research in the Dutch Caribbean here in the Netherlands. In my new department, there are several people that study coral reefs and other freshwater and marine ecosystems from different angles, which makes it a very stimulating research environment. I am also very happy with this fellowship. It allows me to start my own research group, be more independent and develop my own research lines.’

The fact that the fellowship was established to attract female talent was not her primary motivation to apply, but she does support this idea. Schoepf: ‘It is well established that women in STEM often experience discrimination. Things are a bit better in Biology compared to other STEM fields, but especially when you look at the number of female associate or full professors, there is still a lot to be done. Also here at the UvA. It is critical to not only attract female STEM students, but also to retain them and offer longer-term perspectives. This is where fellowships like the MacGillavry play an important role.’

Science outreach

Back in Australia, Schoepf was actively involved in bringing science to the public and setting an example as a female role model in science. ‘I was part of the prestigious “Superstars of STEM” programme, which aims to smash society’s gender assumptions about scientists and increase the public visibility of women in STEM. It provided a select group of women with special media and public outreach training. We also visited local schools to talk about our work. My goal is to raise awareness for climate change and coral reefs, and at the same time be visible as a female scientist,’ says Schoepf.

She wants to continue these efforts here in the Netherlands. ‘I want to improve my Dutch, to visit schools again,’ says Schoepf. She has also joined the diversity sounding board at the UvA Faculty of Science. ‘We meet regularly and discuss with the Diversity Officer how we can improve diversity, equity, and inclusion at the Faculty, not only for women but for all underrepresented groups.’

CV

2008 MSc, Zoology, University of Innsbruck, Innsbruck, Austria, with distinction
2009 - 2013

PhD, Geological Sciences, Ohio State University, Columbus, Ohio, United States

2013 Presidential Fellowship from the Ohio State University
2013-2019 Postdoctoral Research fellow, Oceans Graduate School, University of Western Australia, Perth, Australia
2016-present Multiple interviews on TV, radio, newspapers and magazines, including a starring role in the prize winning Arte documentary Ocean Heroines
2017-2019 Research Programme Co-Leader & Member of the Scientific Management Committee, ARC Centre of Excellence for Coral Reef Studies, Australia
2018 Young Tall Poppy Science Award, Australian Institute of Policy and Science
2019 Superstar of STEM, Science and Technology Australia
2019-present Assistant Professor and MacGillavry fellow, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, the Netherlands