What does bleached coral reef mean

Dive into the reef

What is a healthy reef, what is a bleached reef?
The intact reef is full of colors and an incredible variety of living things. It has a strong three-dimensional structure that offers a wide variety of ecological niches to many living beings. In the bleached reef, the corals first turn white. Once dead, they are overgrown by algae, which give them a gray-green color. When the dead coral skeletons erode and collapse, the three-dimensional structure disappears more and more and with it many inhabitants. Such reefs no longer fulfill the many functions that are particularly important for us humans, such as the protection of the coasts, tourism, etc.

We heard sad news from the Great Barrier Reef - what happened?
Unfortunately, 2016 will go down in history as the year the Great Barrier Reef experienced its third and worst mass coral bleaching to date. Only 7 percent escaped coral bleaching. Estimates show that in certain regions a third of the corals are dead. Not only is the Great Barrier Reef affected, but coral reefs around the world.

This coral bleaching was triggered by a combination of global warming and a very strong El NiƱo year, which leads to warmer water temperatures in many of the world's seas. Heat is the main stress factor. Intense solar radiation due to calm and few clouds increases the heat stress.

Aside from climate change, there are other pressures on coral reefs. For example, the acidification of the oceans, which makes it increasingly difficult for corals to form their calcareous skeleton. Or overfishing, cyclones or crown-of-thorns that literally eat up the reefs.

Where does your research start?
I research particularly stress-resistant corals found in the Kimberley region of Northwest Australia. These super corals can withstand more stress than other corals because they are found in a very extreme area. I'm trying to study the mechanisms that enable them to do this. This helps us to understand whether and how corals can adapt to climate change. The fact that there are corals like the ones in Kimberley proves that corals as a whole can withstand a lot - but they have to be given enough time for evolution to happen. Unfortunately, climate change is happening so quickly that there is almost no time for them.

How do plastic waste and microplastics affect the reefs?
Microplastics are ingested as food by a large number of marine life and cause great damage. Furthermore, plastic bags and other rubbish often float in the reef and damage reef inhabitants and the corals as they often get stuck on them.

What can we do for the reefs?
As a consumer or a voter, everyone can make a small contribution to directing the market and politics in more environmentally and climate-friendly directions. The most important thing, however, is to reduce global CO2 emissions and switch to renewable energies.

You are a child of the mountains, raised in Innsbruck. How is it that you have committed yourself to a life in the tropical belt?
When I saw the films by Hans Hass as a child, it was immediately clear to me that I wanted to do that one day too: to become a marine biologist and to explore the sea. We spent many summers at the seaside where I would snorkel for hours and that only encouraged me. When I was eleven or twelve my grandma took me on a trip to Egypt. It was then that I saw tropical coral reefs for the first time. That made a deep impression on me and I wanted to learn more about this fascinating ecosystem. Of course you have a lot of dreams as a child, but I never thought of anything better, so to speak, and so I stuck with it. Hans Hass - especially as an Austrian - was my great role model, even if, of course, many others have joined us in the meantime.

I then wrote my final thesis for the Matura on the creatures of the deep sea in high school. There was no question that I would study biology - first in Innsbruck with many marine biology courses, then at marine biology in Vienna, where I finally did my master's thesis on the Red Sea. Then I went to the USA to do my PhD and continue to work on coral reefs. With my move to Perth, Australia, I finally managed to finally live by the sea and have the corals almost on my doorstep.

You spend a lot of time underwater, the focus on the corals. What other reef dwellers do you particularly like?
There are so many that I find it almost difficult to highlight certain ones. Puffer fish because their fin movements look so fun. Octopuses and sepias because of their fascinating play of colors. The colorful nudibranchs or the funny christmas tree worms that often live in the corals. And many, many more!

Do you feel part of the underwater world or are you sometimes afraid, if so, of what?
Most of the time I definitely feel like part of the underwater world and literally like a fish in the water. But you also have to be realistic - there are definitely top predators in the sea who can be dangerous for us. Especially in Australia one is always aware of this somewhere. There are sharks and crocodiles here, or invisible jellyfish that can kill you. However, your own behavior plays a big role and I think it's important to emphasize that the sea is their habitat and not ours.

Which research field would you be interested in if you could start all over again?
Behavioral research. Especially when it comes to highly developed animals that display complex social behaviors, such as dolphins or great apes.