What is marimo?
Marimo is arguably one of nature’s most bizarre creations. Commonly known as algae balls or moss balls, these algae bundles are typically found on lake floors in Japan and Northern Europe. Their fuzzy spherical shape is the result of gentle currents rolling the algae over and over again until they resemble a puffball toy.
Now, researchers from UWE Bristol’s Unconventional Computing Lab have recruited marimo balls to help them develop an autonomous bio-rover that’s powered by sunlight. The invention, dubbed MARS (marimo-activated rover system), is essentially a fully functional rover prototype that has a biological organism as its key component.
As part of the project, the researchers harnessed the power of photosynthesis and the natural rolling of the marimo to create the autonomous machine, which can roam lake beds to monitor water conditions like oxygen concentration and temperature.
How does it work?
The marimo is enclosed within a 3D-printed spherical shell that measures 200mm in diameter. When the marimo undergoes the process of photosynthesizes, the released oxygen bubbles get trapped in the shell rather than escaping into the water.
As more oxygen builds up within the shell, torque increases until the device starts moving. To put it more simply, the oxygen generated as a result of photosynthesis acts as a fuel source for the marimo rovers.
What’s particularly impressive is that in tests the MARS was able to bypass obstacles all by itself. If a large object were to obstruct its way, oxygen bubbles would simply build up inside the shell until the rover became buoyant, enabling it to float over the obstacle.
What are the advantages?
According to the team, the marimo balls are more efficient and easy to operate than conventional energy cells, making them suitable for long-term missions. Other advantages include the fact that they are relatively lightweight, cheap to make, and eco-friendly since they only use light as a power source.
“As most biological processes have been optimized through evolution to be as energy-efficient as possible, they are inherently more energy-efficient than conventional engineering inspired by biological processes,” write the researchers in their study, published in the Journal of Biological Engineering.
What are the applications?
One particular downside is that the bio-rovers aren’t very fast. This makes them suitable for such applications as strategic water sampling and water quality monitoring, inspection of deep underground mines, mediating interactions between underwater animals, as well as other ecological studies.
Study source: Journal of Biological Engineering – Marimo actuated rover systems
