Toby Kiers

Career and research

Kiers is best known for her work on mycorrhizal networks, studying the rates of exchange of nutrients. Her observations are that fungi in the soil behave as economic agents in a free-market system, supplying more phosphorus to plants that are able to deliver more sugar in exchange. Based on this hypothesis, Kiers is interested in developing fungi that behave "altruistically" in their environment to foster efficient plant growth and reduce the need for fertilizers. This interpretation of soil interactions as competition complicated the picture of a collaborative equilibrium that had begun to develop prior. It also allows Kiers to borrow mathematical models from economic theory to characterize nutrient exchanges. To track the flow of nutrients, Kiers has pioneered the use of quantum dots to tag molecules so that they fluoresce and can be more easily differentiated. Her work also concerns the evolution of plant-fungal interactions as the organisms evolve and enter into contact with new partners. Her research is supported by the European Research Council, the Netherlands Organisation for Scientific Research (NWO) and the National Science Foundation.

Kiers's economic interpretation of nutrient exchange is not universally accepted. Others have noted that this perspective anthropomorphizes fungi in a way that may not accurately capture the true dynamics of the system. By assuming that each organism acts to further its own personal gain, the theory neglects the possibility that plants and fungi may exist in a fully collaborative relationship with well-aligned interests.

She helped to create an art installation with Isaac Monté and worked with designer Niels Hoebers to create an animated short film as a visual aid for her research presentations. Her research and comments on mycorrhizal networks were featured in the 2020 book Entangled Life. Kiers has launched a non-profit organization called Society for the Protection of Underground Networks (SPUN) dedicated to informing the public about mycorrhizal networks, protecting biodiversity hotspots, and promoting further research. Kiers founded SPUN to map the biodiversity of the Earth's mycorrhizal communities... [and] is mapping what has been called the "dark matter" of life on the planet. In 2023, Kiers was the subject of the short documentary The Underground Astronaut, directed by Marleine van der Werf as part of the Ammodo Docs series. The film follows Kiers' research into mycorrhizal networks and her efforts to map underground fungal ecosystems.

Personal life

She is married to the poet Cralan Kelder and has two children.

Kiers has been a strong advocate against bioengineered food, demanding that labels clearly indicate the presence of genetically engineered ingredients.