What are corals and why are they threatened?

The answer is not quite so clear, because corals are formed through a fascinating symbiosis. The way tropical corals live is based on a remarkable collaboration between their polyps - the animal building blocks - and microscopic floating algae, the so-called zooxanthellae. These algae live directly in the tissue of the polyps and have a close, symbiotic relationship with the corals.

The polyps, which are clearly animals, contribute to the coral's nutrition by using their tentacles to capture anything that floats near them - from plankton to small jellyfish to organic particles. The zooxanthellae, on the other hand, bring their plant-like abilities and produce nutrients through photosynthesis using sunlight. The coral thus combines the strengths of both partners - the hunting ability of the polyps and the energy production of the algae.

For this reason, many coral species only thrive in light-filled waters (the so-called "photic zone"), where there is sufficient light for photosynthesis. The proportion of photosynthesis in the diet varies greatly between coral species - for some, it can provide up to 80% of the nutrients needed. However, there are also specialized coral species that exclusively hunt and live in lightless depths. This diversity shows the amazing adaptability of corals to different habitats.

If you've ever been to the sea, you may have been lucky enough to experience the fascinating world of coral reefs. Even if you haven't experienced their beauty in person, you still benefit from them - after all, about half of the air you breathe is provided by the ocean.

Carbon dioxide (CO2) is a major component of the greenhouse gas that drives climate change. Coral reefs are often called the "rainforest of the sea" because they help regulate the Earth's climate by absorbing and storing CO2 from the atmosphere - similar to trees. Even though they are not the largest absorbers of CO2, they still play an important role. They are also closely linked to seagrass meadows and mangrove forests, which are important collection points for so-called "blue carbon".

Yes, the financial resources required for such projects can be overwhelming, which is why it is all the more important that we work together to ensure that we can continue to benefit from corals in the future.

Climate change is causing sea temperatures to rise steadily, reaching levels that many coral reefs cannot survive. Persistent heat waves are putting corals under severe stress. As a result of this heat stress, the algae, which normally provide vital nutrients, begin to produce toxic substances.

To protect themselves, the corals shed these algae, causing them to appear white or, in a last attempt to survive, to display bright colors - until they finally disappear completely. Some exceptions, such as corals in the Red Sea, have adapted to higher temperatures over thousands of years.

You are absolutely right. It would be utopian to think that we can bring all the dead corals in the ocean back to life, especially for reefs that are hundreds of kilometers from the coast, the costs would be extremely high.

What we can do, however, is to implement and maintain targeted projects at strategically important locations along the coast and for tourism.

We try to support such projects financially because we love corals and are fascinated by their amazing biology. For us, they are the "trees" of the world's oceans. However, we lack the scientific background to realize our own projects, which is why we prefer to leave it to the professionals like Coral Guardian . In the long term, however, we would like to change that and perhaps even set up our own NGO - but that is still a long way off.

Almost ten years ago we helped with a reforestation project. But traveling around the world just to show you photos and videos of us "planting" corals would be anything but sustainable. In the future we will definitely support one or two projects personally - but we will not lose sight of the ecological footprint. One of our main goals is to raise awareness of the urgency of coral protection, even if restoration is very complex and expensive.

Corals are essential for the biodiversity of our oceans. Coral reefs cover less than 0.2 percent of the Earth's surface, but serve as habitat and shelter for around 25% of all marine biodiversity. They also protect coastlines by acting as natural barriers against strong waves and storms.

But their influence goes even further; they support research, as their substances help in the development of new drugs, including those against cancer. And let's not forget tourism; many people earn their living by diving and snorkeling on coral reefs or by fishing. Corals are of enormous importance for the balance of nature and for our own lives.

There are numerous coral restoration projects around the world, and these are considerably more expensive than tree planting. They involve collecting broken coral fragments from fishing nets and bringing them to nurseries where they are lovingly cared for until they are ready to be reattached to reefs or reef structures. Another method is to take small fragments of coral that have survived rising sea temperatures in the past.

These resilient pieces of coral can be attached to reef structures to create more robust and adaptable reefs. Such projects require not only financial resources, but also continuous care of the corals. Ultimately, these must be placed on artificial reefs and monitored regularly to ensure their success. There is also the option of making building blocks out of clay on which the polyps can settle. The professionals at rrreefs in Zurich are already doing a great job. Check out their homepage.

Unfortunately, the ideal conditions for successfully implementing such projects do not exist everywhere in the world. Unfortunately, climate change is already very advanced and in regions where ocean warming and acidification are much more pronounced, this makes the implementation of such projects much more difficult.

You raise an important point. It is true that travel, especially flying, contributes to global warming and exacerbates the problems affecting corals and other ecosystems. Diving, especially in busy areas, can also be harmful if not practiced responsibly. At the same time, however, it is also important to remember that awareness of the threats to coral reefs can be increased through travel and experiencing the underwater world. This can help promote the protection and conservation of reefs in the long term if tourism is carried out sustainably and with respect for the environment.

So it's about how we combine our passion for the underwater world with responsibility and consideration for the climate - by flying less when possible and focusing on environmentally friendly, sustainable practices in diving tourism