Algae – the green heart of the oceans

It is widely believed that forests are the lungs of the world, determining the quality of the air we breathe. However, few people talk about the silent hero of the Earth’s atmosphere – it is the microscopic algae swimming in the seas and oceans, meanwhile, that produce about 50 percent. of all oxygen on the planet. And while they are badly associated with beachgoers dreaming of crystal clear water, algae, or algae, can still give humanity a number of further contributions, including saving lives or powering cars.

From microscopic algae to giant seaweed

Algae are not really taxonomically related. Rather, they are a huge group of the most diverse aquatic organisms capable of performing photosynthesis, or the production of glucose and oxygen, using solar energy and carbon dioxide. Its largest representative is the pear-bearing polychaete(Macrocystis pyrifera), which beats bamboo in terms of growth rate – daily its shoots elongate by up to 60 cm, eventually reaching a length of up to… 60-65 m.

At the other extreme, we have single-celled algae, the smallest of which is the Medakamo hakoo species, discovered by Japanese scientists as recently as 2015 and in an aquarium. This freshwater microalgae is 1 µm or, one millionth of a meter in size.

Algae and their importance in the food chain

The smallest of algae are not only the world’s largest oxygen factory, but also a staple food in marine ecosystems. Because they are self-living, they are the beginning of the food chain – krill, fish and crustaceans feed on them, which in turn fall prey to predatory fish and cetaceans. At the top of this chain are sharks, seals, but also humans, who annually eat about 20 kg of fish and seafood.

Sweet and saltwater algae are also making their way to our plates in pure form. More and more scientists are coming around to the thesis that this will be the food of the future that will save the world from famine. Microalgae are first and foremost an excellent source of protein, the shortage of which will be the biggest challenge of an overpopulated planet. They reproduce at an admirable rate, and they do not need land to grow them, which we will also soon begin to lack. It has even been suggested that it is algae that will one day replace meat in the human diet.

Industrial and medical uses of algae

The unique polysaccharides and polyphenols contained in the seemingly primitive algae also open up enormous potential for the world of pharmacology. Previous research shows that they have antioxidant, antiviral and anticancer effects. They can also be used to treat high blood glucose levels and hypertension. When incorporated into toothpaste, they actively prevent tooth decay, and there is growing evidence that they may also protect against neurodegenerative processes. In addition, the microscopic algae appear to be excellent hosts for recombinant proteins, so they are expected to be used in the production of vaccines and antibody therapies.

Algae, is also a virtually unlimited biomass that can be used to produce green fuel – single-celled chlorella, for example, works well in this role. We’ve also already had successful attempts to produce hydrogen and methane from algae, and it’s only a matter of time before they are used to synthesize bio-plastics. In agriculture, meanwhile, micro- and macroalgae are a great prospective fertilizer that can help reduce the use of controversial artificial fertilizers.

Guardian and pest of ecosystems?

It is hard to imagine a world without algae – they are a guarantor of biodiversity in aquatic ecosystems, a trapper of carbon from the atmosphere and a cleaner of streams. But algae are also found in the soil, and in quantities of up to 100,000 cells per g of soil. As producers, they play a key role here, enriching the substrate with organic matter needed by plants for growth.

Among the tens or perhaps hundreds of thousands of algae species, however, there are also villains. In Poland, we have already experienced the destructive potential of golden algae, which in 2022. led to a massive fish plague in the Oder River. Under the right conditions, algae begin to multiply, and their blooms are the cause of ecological disasters. The toxins produced by some species of algae kill fish, aquatic mammals and birds, and can also harm humans.

Even seemingly inconvenient algae in a multiplication situation become a problem, clogging gills, blocking aquatic infrastructure and contributing to coral die-offs. Meanwhile, the process of decomposing large amounts of dead algal biomass consumes huge amounts of oxygen, leading to suffocation of other organisms in ponds and lakes . Unfortunately, according to scientists, climate change favors blooms and will increase their frequency and intensity.