Coral reefs are among the most sensitive ecosystems to climate change, and thus constitute a perfect example of studying the changes taking place on our planet. Scientists are working hard to protect and regenerate them using a wide variety of innovative approaches.
It is estimated that around 500 million people and 25% of all marine species depend on coral reefs, either directly or indirectly. The largest coral reef, about 2300 km long, which has been included in the UNESCO World Heritage List, is the Great Barrier Reef, located off the east coast of Australia. Visible even from space, the Great Barrier Reef is home to hundreds of species of coral, fish and molluscs, several species of sea turtles, and even whales and dolphins.
However, marine tourism and fishing are not all that coral reefs have to offer; multitude of creatures living on and around them offer researchers a unique opportunity to discover new chemical compounds that may aid in the development of new drugs. Unsurprisingly, many scientists familiar with the benefits that can be derived from coral reefs are now sounding the alarm: the world’s coral reefs are dying.
The threats they face are many, and to make matters worse, they stem from all sorts of different reasons. The most important danger factor is undoubtedly climate change with its rise in temperatures which leads to the discoloration of corals. However, this is not the only problem, as pollution and ocean acidification – a subject briefly described here – are equally destructive. Ocean acidification is not caused by the dumping of acids into the water, but by the emission of carbon dioxide into the atmosphere which is increasing globally. The CO2 is then “absorbed” by the oceans as part of a natural carbon biogeochemical cycle that involves both the atmosphere and the hydrosphere (i.e. marine and inland waters), where it exists not only as dissolved carbon dioxide, but also as bicarbonate. and carbonate ions. In addition, ocean currents transport huge amounts of carbon deep in the water layers. CO2 does not directly affect the discoloration of corals, but it significantly hinders their recovery by reducing the concentration of their natural building block – aragonite.
Various reports show that by 2050, up to 95% of the world’s coral reefs will be exposed to heat stress leading to coral bleaching. This probably wouldn’t be such a big problem if it weren’t for the fact that natural reef regeneration is a slow process. In addition, destroyed coral reefs are less likely to reproduce: for example, the average annual growth of the Great Barrier Reef is only 5 to 8 mm! The slow regeneration is therefore the reason why up to 50% of coral reefs have been irretrievably destroyed so far. Unsurprisingly, attempts are being made to protect and regenerate coral reefs and so far around 27% have been saved by declaring them nature reserves. These attempts include a number of methods, such as assisted reproduction, modifications to produce organisms that are more resistant to heat stress, or, for example, artificial reproduction.
It has already been pointed out that reef regeneration is a time-consuming process, however, interesting research results have been published recently regarding 3D printing technologies used to regenerate coral reefs. In ACS Sustainable Chem. Eng. 2021, 37, 12634-12645, the researchers present a method that not only simplifies the procedure for the regeneration of coral reefs, but above all accelerates the regeneration process. For this purpose, 3D printed structures made of calcium carbonate were used. To put it simply, scientists have succeeded in creating an artificial coral skeleton based on the natural skeleton which ensures rapid growth of coral micro-fragments, because there is no need to build a calcium skeleton which forms the base of the structure of the reef. . Unlike other similar methods, this technology is based on the passive colonization of the printed substrate, ie the attachment of coral micro-fragments to the printed skeleton.
3D printing technology is now an integral part of our lives. This not only involves using commercially available filaments such as PLA for “figurine printing”, but is also the subject of extensive research focused on the possibility of employing a number of materials to create entire building constructions (such as the whole bridge running in the Netherlands) or using organic “microbial ink” material to print “living material”, i.e. special capsules for medicines . A number of other uses are also contemplated which are outside the scope of this article. While in 2010 there were only a few publications describing 3D printing-related inventions in patent databases, their number exceeded 4,000 in 2020, with no less than 5,000 publications in 2021. This only proves that 3D printing technology is currently used in many areas of technology, leading to the development of increasingly innovative solutions. In addition to man-made components, living micro-fragments are also more often used to help protect the environment that we as a human race are so determined to destroy.