This episode of SciShow is supported by Spintronics. Spintronics is a new game where players build mechanical circuits to solve puzzles.
Trees have tons of benefits! They get rid of excess carbon dioxide and make tasty, fresh oxygen for us to breathe. But some of the places where it’s hardest to plant and maintain those trees are the same places that need them the most, like big, busy cities. That’s why some researchers are trying to improve on nature’s design by making trees liquid.
To be clear, we are extremely pro-tree on SciShow. Trees help combat climate change by storing excess carbon dioxide from the atmosphere, produce the oxygen we need to breathe, and capture particulates to help purify the air. But as great as trees are, they just don’t make sense to grow everywhere. For starters, trees are big, and they need to be planted in nutrient-rich soil. Space and soil are two things cities don’t have a lot of. Plus, trees’ root systems can cause damage to infrastructure like sidewalks and sewers. And as good as trees are at removing pollutants from the air, they tend to just hold onto them afterwards.
That’s why some researchers are looking into whether we can use not-trees to give us some of the same benefits that trees do. And that’s led them to photobioreactors. Photobioreactors are closed, lit containers that contain lots and lots of tiny, photosynthesizing organisms, all in a carefully calibrated system to allow people to control their growth. Picture a giant, green, glowing water tank full of algae or bacteria. Thanks to photosynthesis, the organisms in the tanks remove carbon dioxide from the environment and release oxygen back into the air.
Besides their potential future as tree juice, photobioreactors have a ton of uses. Like wastewater treatment. When water passes through a reactor, the algae filter out pollutants like nitrogen and phosphorus. They can even grab contaminants like estradiol, which is a hormone found in birth control pills, and larger organic matter, like, you know, the kind you would find in waste water. We’re also discovering that some microalgae produce biological compounds that can be important for things like medications. And when you grow those algae in a photobioreactor, the production of those compounds is controlled and efficient, so it’d be way better than just collecting the compounds from wild algae.
If you want to get all sci-fi about it, photobioreactors could someday be used to remove carbon dioxide and release oxygen in spacecraft, plus grow greens for space salads that are 100% edible. Photobioreactors have the potential to provide many benefits to our environment. Unlike trees, they don’t require roots, stems, or leaves and produce no waste. The LIQUID3 photobioreactor in Belgrade uses a species of single-celled algae that is resistant to high and low temperatures, allowing it to photosynthesize and pump out oxygen year-round. It can do the same work as two ten-year-old trees in the area of a park bench. Plus, photobioreactors are lower maintenance and can be made into any shape, allowing them to be placed in the most polluted areas of a city.
However, photobioreactors are not a replacement for trees, as they do not provide the same aesthetic and mental health benefits of having green spaces. Both tanks and trunks will have a part to play as we try to build cleaner, greener cities.
If you’re curious about the science of electricity, check out Spintronics, a puzzle, graphic novel, and time-traveling educational game. It’s great for kids and adults alike and makes circuits tangible, irresistibly touchable, and deeply intuitive. Learn more about the science of the game at upperstory.com/spintronics today.