My research focuses on how plants interact with soil organisms, how these interactions respond to global change, and what the consequences are for ecosystem functioning. Plants interact with soil organisms, in particular soil microbes, through a variety of mechanisms: they modify the soil environment through their litter inputs and through altering soil nutrient and moisture contents, but they also interact directy with soil organisms throuhg their roots and root exudates. I like to mechanistically unravel those mechanisms and assess their importance for ecosystem functioning in real-world ecosystems, with a particular focus on carbon and nitrogen cycling.

I am doing this research together with my team and my colleagues, and with numerous external collaborators and stakeholders - science is a team effort! I also engage in broader societal discussions around sustainability and nature conservation, and I very much enjoy writing about a variety of topics. 

I lead the Plant-Soil Ecology lab group - you can find more about who we are an what we do on our website.

In addition to my research, I am passionate about instilling an appreciation of soils in the wider public, and about training the next generation of grounded soil scientists who will tackle our grand challenges of sustainable food production, conserving biodiversity, and climate mitigation and adaptation.

I am also a strong proponent of diversity, equity, and transparency in academia and STEM. I blog about these issues, about my science, and about academia in general. 

My current research focuses on understanding the response of terrestrial ecosystems and their functioning to global change. I am particularly interested in how feedbacks between plants and soil microbes are altered under changing environmental conditions, and how a mechanistic understanding of these feedbacks will allow us to predict ecosystem response to climate change, with the ultimate aim of preserving their form and function, increasing their adaptability, and mitigating climate change.

Have a look at all the reserach going on in the Plant-Soil Ecology lab. 

Current and past projects that I am leading are:

Harnessing root-microbe-mineral interactions for climate-friendly soils

NWO-funded project on climate-friendly agriculutural soils - 2023-2028

Soils hold more carbon (C) in soil organic matter (SOM) than vegetation and the atmosphere combined, and only a small loss of this C can exacerbate climate change. The awareness that soils are crucial in the global C cycle has led to many initiatives that aim to increase C storage in agricultural soils. Our understanding of the mechanisms that stabilise SOM has vastly increased in the past decade, with the most important advance undoubtedly being the shift from characterising SOM in terms of recalcitrance, to the importance of microbial transformations and interactions with the soil matrix . In addition, recent experimental evidence shows that belowground organic matter inputs, in the form of root litter and root exudates, are more important for the formation of stable SOM than aboveground inputs. Moreover, amidst growing concern that an increased frequency of extreme climatic events such as droughts and flooding, as we are experiencing in the Netherlands, are turning soils into a C source (Friedlingstein et al., 2006), most of our current understanding of the formation of SOM comes from experiments under ambient climatic conditions. In this project, we will link recent advances in root ecology to test how plants with different root systems affect the formation and stabilisation of soil organic matter (SOM). We will use an integrated approach to both test how root-microbemineral interactions build stable SOM and minimise greenhouse gas (GHG) emissions in real-world agricultural systems, and to elucidate the mechanisms underlying these processes, under current and future climates.

Ecosystem response to drought: unravelling the unexplored role of plant-soil feedback

ERC Starting Grant – 2020-2025

As the world has seen all too well last summer, drought is severely threatening our ecosystems and their functioning. It can cause strong shifts in plant community composition, which might lead to a new ecosystem state from which it is difficult to revert back. These shifts can have severe consequences, including a loss of species, habitat, and ecosystem function. While we would expect drought-adapted species to increase after drought, often we see a counter-intuitive increase in plant species that should be vulnerable to drought. Here, I will test whether these ‘vulnerable’ species, that also happen to be on the rise with nitrogen enrichment and habitat loss, use the fungi and bacteria that live in the soil to improve their own regrowth after drought, and whether this causes persistent shifts in plant community composition. Me and my team will do this by using a number of long-term drought experiments across Europe, and by reviving a Dutch long-term drought experiment at Oldebroek (Veluwe). We will also set up a new field experiment in a chronosequence of abandoned agricultural sites, which form a gradient of different plant communities. Combined with targeted mechanistic experiments, state-of-the-art metabolomics and sequencing techniques, and statistical modelling, these experiments will elucidate the role of changes in soil microbial communities in drought-induced shifts in plant community composition. This knowledge is crucial for predicting and mitigating the effects of drought on our ecosystems and preventing irreversible shifts in plant community composition. 

Developing a trait-based framework for predicting soil microbial community response to extreme events

NERC funded project – 2018-2021

Co-investigators: Chris Knight, University of Manchester; Rob Griffiths, CEH Wallingford

In this project, we will investigate how bacterial and fungal populations that live in the soil are affected by extreme weather events, and we aim to identify the traits that are responsible for this. For example, some groups of bacteria can form spores and thus survive a wide range of stresses, but there might be many other traits that can allow bacteria and fungi to cope with extreme weather events. We will use a unique experiment in which we subject soils from different climates across Europe not just to drought and flooding, but also to heatwave and freezing, and we will combine this with state-of-the-art DNA sequencing and bioinformatics to quantify bacterial and fungal response and to infer the traits responsible for this. In addition, we will measure how the processes that these organisms perform change with these extreme weather events. This work will result in fundamental knowledge on soil bacterial and fungal response to extreme weather events, and in a framework that allows us to predict how soils and their functioning will respond to extreme weather events. This knowledge is of the highest importance for adapting the Earth’s ecosystems to climate change.

The root to stability – the role of plant roots in ecosystem response to climate change

BBSRC David Phillips Fellowship – 2015-2020

This project aims to investigate how plant roots and their exudates affect the response of ecosystems and their functioning to drought and warming. It will focus on grasslands, which cover a large part of the world, and are crucial for biodiversity and carbon and nitrogen storage. Because so little is known about how and why plants differ in their root exudates, we will first look at how different root systems affect the composition of root exudates, and how roots and root exudates themselves respond to drought and warming. Then, in a combination of laboratory and field experiments, we want to find out how roots and their exudates affect the response of soil bacteria and fungi to drought and warming, and how they might affect longer-term ecosystem response to drought and warming. The results of this work might be used to increase the resistance of ecosystems to climate change, for example through sowing specific plant species, or by informing plant breeding programmes.

Ecosystem stability along a primary succession gradient

Royal Society International Exchanges Grant – 2015-2017

Co-investigator: Wolfgang Wanek, University of Vienna

This project tests the hypothesis that ecosystem response to climate change will change along a primary succession gradient in a glacier foreland, and identify the

relative role of soil and plants in modifying this response. Specifically, we will test whether the resistance of plant performance and soil processes to warming and drought will increase with ecosystem age. We hypothesise that with increasing ecosystem age both plant performance (photosynthesis and respiration rates, and aboveground and belowground biomass) and soil processes of C and N cycling will become more resistant to both drought and warming. We use the well-characterised Odenwinkelkees glacier foreland chronosequence to test these hypotheses. This project will provide insight into fundamental controls of ecosystem response to climate change, and will quantify the relative role of soil and plants in this response.

Primary succession and ecosystem nitrogen retention in glacier forelands

British Ecological Society Early Career Project Grant – 2012-2016

Although the productivity of most terrestrial ecosystems is limited by the availability of nitrogen (N), very little is known about the factors that regulate ecosystem N retention and loss. During primary succession, soil microbial communities become more fungal-dominated and plant communities more N-conservative. My recent research has shown that soils with a fungal-dominated microbial community, as opposed to one dominated by bacteria, retain N better and, as a result, have lower N leaching losses. In this project, I hypothesise that ecosystem N retention will increase as primary succession proceeds and, specifically, that fungal-dominated soil microbial communities of late-successional seres will immobilise, and thus retain, more N than bacterial-dominated microbial communities of early-successional stages. To address this hypothesis,I used a chronosequence approach on glacier forelands, which are commonly used for studies on primary succession, toasses how ecosystem N retention changes as ecosystems develop, and how this relates to shifts in plant and microbial community structure.I collected soil from three well-described Alpine glacier foreland to test my hypotheseis in a mechanistic laboratory experiment: the Rotmoos and Ödenwinkelkees glaciers in Austria, and the Damma glacier in Switzerland.