correspondence with
Saana Kataja-aho

Could you share how you ended up researching soil? What drew you to this field? And if possible to explain shortly - how has your perspective evolved over time?

Saana: I became a researcher somewhat by chance. I had been interested in ecology, forests, plants, and insects since the beginning of my master's studies, but somehow I felt that the academic world and a career as a researcher were very foreign to me during my studies. I thought that I wasn't cut out for it and wouldn't be able to focus on such a narrow field. However, I then noticed that there was a PhD position available on the effects of stump harvesting on soil decomposers. I thought this might be something I could study, as it was applied research and involved forests and insects. I applied for the position and got it. Then I widened my research to include vegetation and a little bit of microbiology. So I was able to combine human impact, forests, ecology, plants, and insects, and on top of that, soil. And the more I researched, the more interesting things became. Soil is a really interesting environment and such an essential part of ecosystem functions. Perhaps it is precisely this diversity and complexity that has surprised me along the way. And how little is known about it, even though we already know something.

We often think of soil in relation to agriculture, but forest soils seem to be somewhat overlooked. Why do you think it’s important to pay more attention to forest soils, and how do they differ from soils used for farming crops? Can you tell us more about the specifics of soil in northern boreal forest ecosystems - what makes these soils unique, and what are some of the challenges in studying them?

Saana: As a general rule, it can be assumed that forest soil has been relatively untouched by human activity. Over the long term, forest soil has not been disturbed as much as agricultural land. However, we cannot rest on this thought, as forest soil is also being modified. At times, it has been cultivated quite intensively, for example by plowing and digging deep ditches. Since then, soil cultivation methods in commercial forests have become at least somewhat less intensive. However, excessive management does not lead to good results in the big picture. Forest soil has formed over thousands of years since the Ice Age, and cultivation changes this structure. Soil acts as an important carbon store, which means it affects greenhouse gas concentrations and, through this, the climate and global warming. In addition to retaining and purifying water and storing minerals, it recycles nutrients, i.e., decomposes dead matter into smaller parts that plants can use for their growth. 

Soil also serves as a growing environment for trees and other plants and as a home for many animals. Soil is home to a huge variety of organisms, ranging from microscopic single-celled organisms to mites, nematodes, springtails, and large animals measuring a few millimeters in length. Earthworms are probably the best-known purely soil-dwelling animals, but many vertebrates also make their nests in the ground, even if they live on the surface. Badgers, for example, are quite skilled at building underground tunnel systems. In addition to these, the larvae of many insects live in the soil and then, once they have matured, migrate elsewhere, perhaps with wings. 

Studying soil and its organisms is challenging because soil is so diverse and mosaic-like. In one spot, there may be fine sand, next to it pieces of rock, then traditional forest soil with a layer of humus, and then suddenly mull. There are millions, even billions, of organisms in a square meter of soil. Most of these organisms are so small that they require a microscope or expensive and complex DNA separation methods to identify. Studying samples is slow and requires special expertise. On the other hand, it is not easy to even extract these soil animals from the ground, as different animal groups require different methods. In order to be able to say anything general, huge amounts of soil samples would have to be taken and examined, which requires money, time, and expertise. 

What do you think are, or could be, some of the most interesting and powerful points of intersection between art and research? How can these fields complement each other in ways that deepen our understanding of complex topics like soil, ecosystems, or environmental issues? 

Saana: The various exhibitions, photographic and art exhibitions, in which soil/ecosystems/plants are a part, are impressive and spectacular and often also of interest to people. In addition, 'zooming in' on the microscopic world could be of interest to a large audience. If I were, say, a designer making patterns and prints, I would definitely use a microscope and, for example, plant seeds, plant parts, small soil particles and soil animals as my models and draw inspiration from them, because they look so amazing under the microscope. And why not animations etc. that tell a story about the diversity of soil, like the recent Turilas ja Jäärä animation. And animations now often target children and young people, they are the future, so that's why especially something that would get young people excited about understanding and caring for soil and biodiversity in general.


How are soil, forests, and microbes connected to planetary wellbeing? How do they contribute to the wider ecosystem functions in brief ? What needs to change in people’s idea of soil? 

Saana: Soil is part of a bigger entity. It is important for people to understand the huge role soil plays in very fundamental parts of ecosystem functioning and thus as part of planetary well-being. Just in general, understanding that we are totally dependent on functioning ecosystems for oxygen, clean water and food, among other things, would be really important. And where and why we get oxygen, clean water, food, building materials etc. from nature is very much dependent on productive and healthy, properly functioning soils. An asphalt field does not clean water, recycle nutrients, does not bind carbon from the atmosphere and does not produce food, oxygen or building materials. It rarely serves as a habitat for any organism.

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​Saana Kataja-aho works as a university teacher at the University of Jyväskylä. She holds a PhD in ecology and evolutionary biology. Her research has focused on investigating the effects of human activity, particularly forest management, on soil decomposer communities and vegetation, which she has done in collaboration with leading Finnish soil scientists. Soil ecology research is closely linked to ecosystem functioning, climate change, and biodiversity. Kataja-aho has also contributed to several non-fiction books and written, among other things, about her research subjects, springtails, in the book Elämää maan kätköissä (Life in the Soil). She has also been involved in implementing MOOC courses on planetary well-being at the Open University of Jyväskylä, which she has also presented and communicated in the European Association of Distance Teaching Universities (EADTU), and which have been very well received. Kataja-aho currently works in teaching-oriented positions at both the Open University of Jyväskylä and the Department of Biological and Environmental Science at the Faculty of Mathematics and Science. She is also one of the MUUMAA team researchers.