The earth has a problem: Too many greenhouse gases in the atmosphere are causing global warming. Climate change not only heats water and land more, it is also causing icebergs, glaciers and permafrost to thaw, causing sea levels to rise and the release of even more greenhouse gases. The consequences for humans and animals will be devastating if we don’t stop this development – or even reverse it.
But the salvation of the world could be right before our eyes. At least there are some hopeful approaches that promise climate protection and a sustainable circular economy at the same time. Projects with so-called blue carbon, better known under its English name blue carbon, sound particularly promising. The term refers to the carbon that is bound in the oceans by marine organisms such as mangrove trees or seagrass beds.
Seagrass, for example, stores a lot of carbon dioxide in the sediment over the long term. After it dies, the plant can be used as a natural and flame-retardant insulating material, as has been the custom in the North Sea for centuries. But there is one disadvantage. “The seaweed is a very sensitive seaweed,” says Mar Fernández-Méndez, marine biologist at GEOMAR Helmholtz Center for Ocean Research Kiel, in an interview with NewsABC.net. Too many excretions and fertilizers from agriculture, animal husbandry and aquaculture end up in the sea, which the seaweed cannot tolerate. The sea plants are dying off in large numbers worldwide.
Algae can store large amounts of CO2
Afforestation of seagrass meadows on a large scale is therefore difficult, even if their protection is still important. Because the plants provide food and habitat for various sea creatures. They also keep the water clear and the sediment stuck to the coast, thus preventing coastal erosion.
However, other blue carbon organisms such as macroalgae, i.e. large algae, which are also known under the name of seaweed, have the potential to bind significantly more CO2 again worldwide. “Macroalgae that can grow in swimming form will be the future hit for storing carbon,” says the marine biologist. These include the brown algae Sargassum or Kelp. “The macro algae Sargassum fluitans or natans for example, it can grow drifting with little nutrients anywhere on the oceans. ”
Macroalgae do not need fertilizers or fresh water to thrive. They can therefore be grown on huge areas with little effort. “We always think of trees as the gold standard for CO2 storage. They say: If we want to save the world, we have to plant as many trees as possible. Unfortunately, that’s not true, ”says the scientist. A normal tree only stores a large amount of carbon dioxide and only part of it in the soil when it is older. The rest can get back into the atmosphere.
“The sea will be our solution”
In addition, trees do not grow everywhere. Only a few of them can be found in the mountains or in the steppes and deserts. In the other regions they always have to compete with settlements and agricultural areas. In Germany alone, 56 hectares of soil fall victim to land erosion every year. Forests and meadows have to give way to new houses, factories and roads. In the tropics, rainforests are being cleared in order to gain land for agriculture and livestock farming. Afforestation is also becoming more and more difficult in the face of climate change. In the future, trees in Germany will not only have to withstand more heat and drought than in the past, but will also have to withstand the frost in winter.
The sea, on the other hand, has one big advantage: it’s huge. The oceans cover 70 percent of the earth’s surface and, due to their depth, make up 99 percent of the habitat of our blue planet. But despite its size, the potential of the sea is often overlooked, says Fernández-Méndez: “So far we have always exploited the sea and used it as a garbage dump. But I think now is a turning point. The sea will be our solution. We have to ask ourselves: How can we use these huge resources that we have out there in a meaningful and sustainable manner? “
Because algae can also pose a threat. If they grow too close to the surface, they prevent light from entering the water. This is fatal for the plants and animals living there. This also applies in the Caribbean Sargassumthat is washed up en masse on the beaches as a nuisance. “If too many nutrients get into the water, they can cause large algal blooms and endanger valuable coastal ecosystems. That is why we have to learn how we can cultivate and control macroalgae sustainably, ”says the marine biologist. Intensive research is currently being carried out on this so-called “marine permaculture” in Asia. “In Europe we have long underestimated how valuable macroalgae can be,” says Fernández-Méndez.
An algae project wants to win the CarbonX Prize from Elon Musk
The idea: that Sargassum or other macroalgae should not grow on the coast, but in certain zones on the open sea. The algae could then be collected, compressed and then submerged in the deep sea – together with the carbon stored in them. This requires large ships or fixed platforms, but the oil industry and large-scale fisheries are familiar with offshore infrastructure. “The best engineers and skilled workers in the offshore oil industry know how to do it. If you could win these minds from the oil companies and other maritime industries, then we will definitely be able to do it, ”the marine biologist is convinced.
A consortium in which she participates wants to win the CarbonX Prize from Elon Musk. The billionaire and head of Tesla and SpaceX has offered $ 100 million for projects that can remove CO2 from the atmosphere. Fernández-Méndez believes that pioneers like Musk are important for the upheaval. She wants a spirit of optimism, comparable to the Apollo mission 60 years ago. “In the early 1960s, the US decided that it would go to the moon by the end of the decade. And then they put a lot of money and energy into the space program, ”says Fernández-Méndez. “We need that now for the oceans. We have enough smart people on earth with different expertise. ”This is a revolution that needs everyone – not just marine biologists.
But algae are also real all-rounders: cows fed with it emit 82 percent less methane. They are also suitable as food for people and are already firmly established in Asian cuisine. “The world population continues to grow and everyone wants to eat something. That is why new protein sources are being sought, ”says the scientist. This is why the United Nations has been trying since 2003 to make insects instead of beef or pork more palatable to people in the fight against hunger and climate change. But due to the western eating habits, it still costs some effort. “I think people have fewer problems eating algae than insects,” says Fernández-Méndez.
Will algae be the new oil?
Algae could also be used to produce fertilizers, biofuels, biogas and bioplastics. “You can do a lot with it. There’s a huge new market that’s just developing, ”says the marine biologist enthusiastically. Many new companies are currently being set up in this field.
Will algae be the new oil? “I think so,” she says and laughs. “The oil industry made various products and emitted CO2 into the atmosphere. And now we could work with the algae industry to create new products that can replace them, while capturing CO2 that has been emitted over the past few decades. “
There is even hope that even the problem of plastic waste in the ocean can be partially solved. “Sargassum collects in the same way as larger pieces of plastic in the ocean. Maybe the plastic could go along with that Sargassum be sunk. We don’t yet know whether this will work, ”the scientist points out. It is important to find ways to be more sustainable without harming the oceans. “We don’t have all the answers yet. But I think it’s important to have big visions. “