How do we show the importance of invisible soil organisms?


Dr. Stefan Geisen

Researcher, Netherlands Institute of Ecology



This blog may not be the best platform to promote soil biodiversity – we all appreciate soil biodiversity and understand its importance. But this is not a layman´s view. As such, we need to continue making soil biodiversity more mainstream both in science as well as for the general public. It is easy to see that we all depend on soils for our food, and if soil is degraded, we suffer. It is also easy to show the importance of soil biodiversity by highlighting soilborne pathogens and how they can reduce crop yield. That is a start. The next step is more difficult: how can we show the importance of the mostly invisible things in soils that counteract pests (e.g. plant-growth promoting bacteria), increase plant performance (e.g. mycorrhiza and rhizobia), stabilize soils and increase soil quality (e.g. fungal hyphae and earthworms)? With the exception of earthworms where you see them directly or via burrows and casts, we basically need to believe in (scientific) experiments and research. As most soil organisms are hidden in the opaque and dark soil matrix, we need methods to uncover their presence, abundance, biomass, diversity and function.

Final discussion of the GSBC roundtable on methods to study soil biodiversity.

Final discussion of the GSBC roundtable on methods to study soil biodiversity.

For that I initiated a roundtable at the Global Soil Biodiversity Conference in Nanjing, China in 2017. I invited experts in several groups of soil biodiversity including viruses (Ville-Petri Friman), bacteria (Laurent Philippot), protists and microfauna (myself), microarthropods (Huijie Gan and Valerie Behan-Pelletier), and macrofauna (Alexei Tiunov). All gave an overview of these diverse aspects of soil biodiversity with a focus on best methods to study their respective specialty. Diana Wall then provided a perspective on the functional importance of soil biodiversity for ecosystem functions and how to promote soil biodiversity to a wider audience. We had fun and insightful presentations that started a great discussion with the audience. This made us think that a methodological overview would be helpful for more integrative soil biodiversity research. We added some experts on other groups of soil organisms and methods (Emilia Hannula, Arjen de Groot, Maria Briones and  Zoë Lindo) and wrote a perspective article — the first to be published in Soil Biology & Biochemistry. Here we provide an overview of biodiversity in soil, their importance, interactions in food-webs and why we should keep in mind that distinct groups of soil organisms inhabits soil at different scales. Most importantly, we provide an overview of methods to study soil biodiversity including its functioning and include a guide for methods (combinations) that allow assessments of soil biodiversity. One of the main points we highlight is the importance of integrative studies on soil biodiversity, using several methods, including different organismal groups and functions - a perfect “excuse” to collaborate and increase the scientific value of a particular study!

A framework for studying soil biodiversity (originally published in a  paper  in Soil Biology and Biochemistry).

A framework for studying soil biodiversity (originally published in a paper in Soil Biology and Biochemistry).

This work focused mostly on scientists that are interested in expanding their method portfolio to extend soil biodiversity research or to add aspects of soil biodiversity to their research. Therefore, this rather detailed work is not likely to extend beyond the scientific sphere and reach the general public. For that, stay tuned for an upcoming paper and blog focusing on the promotion of soil biodiversity beyond scientific circles!