Artwork by Katelyn Solbakk
Due to its ability to survive the harshest environmental conditions, the tardigrade is probably one of the more famous microscopic organisms, but it is more common in freshwater and not something we typically see in soil samples.
This amoeba is swallowing up a piece of green algae. The amoeba has no defined body shape, and uses “false feet”, also known as pseudopods, to move around and capture food. The soil in this image is very rich in organic material and has many threads of fungal hyphae as well as bacteria helping to bind soil particles into aggregates, creating a strong and resilient soil structure that is also good habitat for soil organisms. In the top left corner is a ciliated protozoa in the genus Stylonychia, which is common in both soil and freshwater. Several small round flagellated protozoa are also seen to the left of the amoeba.
The illustration is a simplified glimpse into what it might look like in the area around a plant’s roots in the soil. The cloudy greenish substance represents exudates that are secreted by the root, which attracts and feeds colonies of bacteria. Mycorrhizal fungi have begun to colonize this root as well, inhabiting both inside and outside the root. They will help extend the root network, allowing the plant greater access to nutrients. A few larger organisms such as flagellates (small protozoa) and ciliates are swimming around too, grazing on the bacteria and freeing up nutrients in a form plants can use.
Difflugia is a genus of testate amoebae that builds its shell using particles from mineral or organic sources. They collect materials from their environment, or from the food they have eaten.
Rotifers are multicellular animals that also play an important role in nutrient cycling in the soil. They are filter feeders, using rows of cilia around their mouthparts to create a vortex, much like Vorticella sp., which pulls water and food particles into the rotifer’s mouth. There are many different kinds of rotifers; depicted is a bdelloid rotifer. There are over 450 species of bdelloid rotifers, and this is a generalized depiction of them. Just behind and to the right of the rotifer you can see a naked amoeba sliding through the soil using its pseudopods (it almost looks like a piece of gum stuck to the wall). The small particles flowing in a circular motion around the rotifer are bacteria, which the rotifer is feeding on, and there are also various fungal hyphae seen woven throughout the soil aggregates.
Vorticella sp. Is a genus of ciliates (protozoa) that can be found in the soil. They are usually seen fixed to soil particles by a stalk which can coil up like a spring if Vorticella is disturbed. They can also be seen swimming freely on occasion. This protozoa is a filter feeder, using a ring of cilia (tiny hairs) around its mouth opening to create a whirling vortex in the water, sucking in particles of food. Vorticella mainly feeds on bacteria. To the left of Vorticella you can also see a small flagellate called Euglena sp., swimming by. Looking at the surrounding soil, you can see that at a microscopic level soil is much more than “dirt”. It is a diverse and fascinating habitat, made up of many different fragments and particles of matter in different stages of decomposition and recycling, held together by bacteria slime, fungal threads and other organic matter.
The two large protozoa pictured are ciliates of the genus Euplotes. They use long hairs called cilia to swim and control movement in the soil water. The three green protozoa on the left side of the picture are flagellates. Flagellates are typically smaller than ciliates and travel using only one or two long whip-like tails. When protozoa eat bacteria, they release the nutrients held in the bacterial cells back into the soil in a form plants can use. This makes protozoa very important members of a healthy soil food web.
Testate amoebae are another kind of protozoa that can be very common in soil. We often see testate amoebae in forest soils along with many fungal hyphae. Amoebae move by forming “pseudopods” or false feet to push or pull themselves around. It is usually difficult or impossible to see the living amoeba within its shell (test) because the amoeba itself is transparent and often hiding inside the shell.
The nematode is trapped by predatory fungus. Nematodes use chemical sensing to find food, so the fungus emits an attractive chemical in the ring cells to draw the nematode into them. Once a nematode is within the ring, the cells swell up like a balloon forming a tight collar. The nematode cannot break free and quickly dies. Fungal hyphae then grow into the nematode’s body to digest it. In this image the fungus is growing on a plant root, surrounded by root hairs. The root feeding nematode (identified by the stylet) was caught by the fungus while trying to feed on the root, so by trapping the nematode to feed itself, the fungus has also helped to defend the plant.
In stark contrast to the active, robust soil ecosystem seen in the other drawings, this soil is in poor ecological health. There is little life or evidence of microbial activity. Two small flagellates, some of the hardy pioneering life forms that can survive these harsh conditions, scout for bacteria to eat. The soil is compacted, sterile, and dead. Instead of soft organic material and porous aggregates, the environment is a dense wall of cold, sharp mineral particles. There are few hiding places or food sources available, so biodiversity is severely limited.
About the Art
Microorganisms are abstract and alien. I wish we could see protozoa and bacteria in their natural habitats without special tools or preparations, the way we can observe a deer in the forest simply by looking at it. Unfortunately, we can’t just stick our heads or cameras down into the soil to watch the ecosystem at work, so I use my imagination and experience with the microscope to imagine what it might be like if we could. I try to draw soil creatures as they might look if we could shrink ourselves down and meet them face to face.
My digital illustrations are hand drawn using a Wacom Cintiq. I don’t use photo overlays or special tricks to create textures or other effects; everything is done by hand using the Wacom pen. It’s a lot like drawing with ink or coloured pencils, but with a little more flexibility offered by the digital medium.
Soil life illustration - Speed painting
My name is Katelyn Solbakk (Weel), I’m originally from Ontario, Canada. I studied Environmental Sustainability at Lakehead University in Orillia, where I was fortunate enough to work as a research assistant analyzing protozoa and diatoms in natural freshwater biofilms. I now live in Norway, where my experience in the university lab landed me a job studying soil life in agriculture and helping other people discover the mysterious world of microorganisms. I’m passionate about sustainable agriculture and environmental protection, and I hope that my artwork can help bring people a little bit closer to the invisible and underappreciated world of microbiology that we depend on for so much.
If you’re interested in prints, commissions, if you would like to use my illustrations in a publication or display, or if you have any comments or questions about my work please get in touch! I’d love to hear from you.
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