UnEarth Magazine.

Words by Natan Siekierka, Art by Maria Mayer

It’s almost certain that anyone who’s into water-related hobby will have had a bad experience with microbes. Of course, the severity of this can vary wildly; your pond being a bit murky isn’t comparable to coming down with Cryptosporidiosis after taking a dip in a badly managed waterway. However, no matter how sour of a taste this experience left, I ask you to keep an open mind, and let me tell you about how these organisms are underappreciated, underrepresented, and underutilised. 

To get the obvious out of the way, I’m not going to be defending pathogens like Cryptosporidium. Instead, we’re going to discuss two large groups of organisms: algae and phytoplankton, though this distinction is relatively minor. Phytoplankton is a term used to refer to a wide range of single celled aquatic organisms that can perform photosynthesis (fun fact, the name comes from the Greek words “phyton” (plant) and “planktos” (wanderer)). Algae, in turn, refers to a number of aquatic photosynthetic eukaryotes- both uni- and multicellular. So far so good, but why care about them? After all, algae barely contribute to the total plant biomass, and phytoplankton is so small, so they can’t have that much impact, right? 

Well, about that… despite their tiny size, algae and phytoplankton are actually responsible for at least 50% of global oxygen generation, making them not only a key source of oxygen, but also carbon sink. They can achieve this by having generally simpler structures. By limiting the amount of non-photosynthesising cells and using different pigments, they can absorb more of the incoming energy from the sun, which results in photosynthetic rates at least 20x higher than that of a typical plant. Considering that the light availability in the ocean is- to put it lightly- less than ideal, it would be interesting to see just how efficient you could make this system on the surface.  

Imagine a tree… now make it biopunk 

A team from the Institute for Multidisciplinary Research at the University of Belgrade, Serbia thought the same, and so they created Liquid3, aka “Liquid Trees”. Despite its very scifi-esque name, the Liquid3’s principle is relatively simple- a large glass tank filled with water and microalgae that pumps in polluted air which is then cleaned by the algae via photosynthesis and pumped out. Apart from reducing CO₂, the unit also acts as a bench, phone charging point, and a street lamp- all powered by a solar panel located at its top. On top of all this, it’s allegedly as efficient at cleaning the air as two 10-year-old trees, while also filtering out heavy metals and taking up less space Brilliant! Let’s start tearing up the trees then, the age of wood is over! 

…Or maybe not, actually. The creators explicitly said that the goal is “not to replace forests but to use this system to fill those urban pockets where there is no space for planting trees”. Despite all of its advantages, the Liquid3 fails to provide several benefits of its natural counterparts, such as giving shade, facilitating wildlife, and- in the cases of actual community-oriented city planning– providing free, fresh produce like fruit and nuts. Furthermore, there is also the matter of maintaining the unit, with at least partial water changes being required to keep the concentration of algae at a level that doesn’t interfere with the efficiency. 

Waste not, Want not 

Humans aren’t known for their foresight, and this is evident with the amount of pollution that we cause. While we have already discussed how algae can be used to clean air pollution, there is also research into their uses in cleaning contaminated water, and potentially soil. 

It’s well known that being exposed to heavy metals is detrimental to health, not only in humans, but in most species. However, rules are meant to be broken, and so there’s always exceptions, which have led to research in bioremediation- the use of organisms to clean pollutants and- ideally- recover valuable materials. One subfield on this is phycoremediation, which utilises algae (or microalgae). Some strains of microalgae have been found to be highly resistant to heavy metals, often going as far as to accumulate and detoxify them. While this is a great method of simply removing the pollutants, there are also ways by which these can then be recovered, such as burning the algae and extracting heavy metals from the ashes. Not only does this help limit the environmental damage caused, but it could also allow companies to reclaim some of the materials lost during production, decreasing their demand for resources, the extraction and production of which is often very damaging to the environment.  

Of course, it’s not a good idea to just dump a load of algae into a lake that’s been contaminated by mining runoff and hope for the best, and research is still ongoing into how exactly this could be implemented, with the techniques only used at very small scales for now. But who knows, maybe one day we’ll get to the point where the use of technologies like this will be commonplace, and people will be able to enjoy areas long since cleaned of pollution by algae. Maybe they’ll relax on benches providing clean air in the midst of a bustling city normally devoid of any plant life. For now though, let’s just be thankful for these tiny organisms, appreciate the every second breath that comes from them, and maybe try to be a bit less frustrated the next time that a perfectly managed aquarium inexplicably turns green and murky.