Droevendaalsesteeg 10
6708 PB Wageningen
The Netherlands
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About
Chemistry is all around us! With my background in chemistry I assist in ecological research wherever I can.
Biography
Since the end of 2011, Iris Chardon works as a research assistant within the Microbial Ecology department of the Netherlands Institute of Ecology.
One of her main drivers is developing and/or optimising analytical methods, gaining and transferring knowledge, and thereby contributing to the development of others. Besides that, she is involved in research projects.
Iris is specialized in chemical analyses of soil, sediment, plant and headspace samples. She is responsible for three different gas chromatographs for measuring greenhouse gases, a laser diffraction analyser and a TOC analyser. Next to that she gives advice to (PhD-) students and (postdoctoral) researchers about nutrient or enzyme analyses, and instructs them for performing extractions or destructions. She analyses the extracts with ICP-OES, LC-MSMS, an AutoAnalyser or an Element Analyser.
From 2019 till 2023 she was involved as a research assistant within the TTW project ‘SmartResidue’, together with Paul Bodelier, Stijn van den Bergh, Gerard Korthals and Wietse de Boer. The project aimed to lower the greenhouse gas emission by turning agricultural soils into sinks of methane after application of bio-based residues. The mechanisms of this residue stimulated methane uptake have been investigated. Iris arranged the purchase of a laser diffraction analyser via a public tender, made the analyser operational, and developed methods to measure soil aggregate stability and particle size distribution with laser diffraction. Next to that, she performed many GC analyses, field screenings, DNA isolations, qPCR assays, nutrient analyses, PLFA extractions and much more.
Feel free to visit her LinkedIn page for more information: https://www.linkedin.com/in/ichardon/
Research groups
CV
Employment
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2021–PresentMember of Research Integrity Advisory Board
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2019–PresentResearch Assistant TTW-project SmartResidue
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2011–2019Research Assistant Chemical Lab
Publications
Peer-reviewed publications
Improved methane mitigation potential and modulated methane cycling microbial communities in arable soil by compost addition
https://doi.org/10.1093/ismeco/ycaf139The global atmospheric concentration of the potent greenhouse gas methane (CH4) is rising rapidly, and agriculture is responsible for 30%-50% of the yearly CH4 emissions. To limit its global warming effects, strong and sustained reductions are needed. Sustainable agricultural management strategies, as the use of organic amendments like compost, have previously proven to have a potent CH4 mitigation effect in laboratory experiments. Here we investigated, using an extensive field study, the effect of organic amendments on the CH4 mitigation potential and CH4 cycling microbial communities of arable soils. Organic-amended soils had higher potential CH4 uptake rates and an improved potential to oxidize CH4 to sub-atmospheric concentrations. Also, we showed for the first time that the methanotrophic and methanogenic microbial communities of arable soils were unequivocally altered after organic amendment application by increasing in size while getting less diverse. Compost-amended soils became dominated by the compost-originating methanotroph Methylocaldum szegediense and methanogen Methanosarcina horonobensis, replacing the indigenous methane cycling community members. However, multivariate analyses didn't point out type Ib methanotrophs like M. szegediense as significant driving factors for the observed improved soil CH4 uptake potential. Conventional type IIa methanotrophs like Methylocystis sp. also had higher differential abundances in organic-amended soils and are speculated to contribute to the improved CH4 uptake potential. Altogether, the results showed that compost serves as a vector for the introduction of CH4 cycling microbes and improves the soil's CH4 uptake potential, which emphasizes the potential of organic fertilization with compost to contribute to CH4 mitigation in agricultural soils.
Soil aggregate stability governs field greenhouse gas fluxes in agricultural soils
Agriculture is responsible for 30–50% of the yearly CO2, CH4, and N2O emissions. Soils have an important role in the production and consumption of these greenhouse gases (GHGs), with soil aggregates and the inhabiting microbes proposed to function as biogeochemical reactors, processing these gases. Here we studied, for the first time, the relationship between GHG fluxes and aggregate stability as determined via laser diffraction analysis (LDA) of agricultural soils, as well as the effect of sustainable agricultural management strategies thereon. Using the static chamber method, all soils were found to be sinks for CH4 and sources for CO2 and N2O. The application of organic amendments did not have a conclusive effect on soil GHG fluxes, but tilled soils emitted more CO2. LDA was a useful and improved method for assessing soil aggregate stability, as it allows for the determination of multiple classes of aggregates and their structural composition, thereby overcoming limitations of traditional wet sieving. Organic matter content was the main steering factor of aggregate stability. The presence of persistent stable aggregates and the disintegration coefficient of stable aggregates were improved in organic-amended and no-tilled soils. Predictive modelling showed that, especially in these soils, aggregate stability was a governing factor of GHG fluxes. Higher soil CH4 uptake rates were associated with higher aggregate stability, while CO2 and N2O emissions increased with higher aggregate stability. Altogether, it was shown that sustainable agricultural management strategies can be used to steer the soil's aggregate stability and, both consequently and outright, the soil GHG fluxes, thereby creating a potential to contribute to the mitigation of agricultural GHG emissions.https://doi.org/10.1016/j.soilbio.2024.109354The intrinsic methane mitigation potential and associated microbes add product value to compost
Conventional agricultural activity reduces the uptake of the potent greenhouse gas methane by agricultural soils. However, the recently observed improved methane uptake capacity of agricultural soils after compost application is promising but needs mechanistic understanding. In this study, the methane uptake potential and microbiomes involved in methane cycling were assessed in green compost and household-compost with and without pre-digestion. In bottle incubations of different composts with both high and near-atmospheric methane concentrations (∼10.000 & ∼10 ppmv, respectively), green compost showed the highest potential methane uptake rates (up to 305.19 ± 94.43 nmol h−1 g dw compost−1 and 25.19 ± 6.75 pmol h−1 g dw compost−1, respectively). 16S, pmoA and mcrA amplicon sequencing revealed that its methanotrophic and methanogenic communities were dominated by type Ib methanotrophs, and more specifically by Methylocaldum szegediense and other Methylocaldum species, and Methanosarcina species, respectively. Ordination analyses showed that the abundance of type Ib methanotrophic bacteria was the main steering factor of the intrinsic methane uptake rates of composts, whilst the ammonium content was the main limiting factor, being most apparent in household composts. These results emphasize the potential of compost to contribute to methane mitigation, providing added value to compost as a product for industrial, commercial, governmental and public interests relevant to waste management. Compost could serve as a vector for the introduction of active methanotrophic bacteria in agricultural soils, potentially improving the methane uptake potential of agricultural soils and contributing to global methane mitigation, which should be the focus of future research.https://doi.org/10.1016/j.wasman.2023.07.027
Projects & collaborations
Projects
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ClipsMicro: Climate proof soils by steering soil and residue microbiomes
To mitigate climate change, global agricultural soils needs to store more carbon and emit less greenhouse gasses (GHG). In ClipsMicro, together with partners in agro-business, this is realised by steering soil microbes by application of novel, refined compost and crops that can reduce emissions of GHG.
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SmartResidue
This project will investigate residue-stimulated atmospheric methane oxidation, and aims to elucidate its occurrence in field conditions, responsible microorganisms, underlying mechanisms and controlling factors.
Outreach
Categories
Featured in
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Impression of the King's visit to NIOO
Earlier this month, His Royal Highness King Willem-Alexander paid a working visit to the Netherlands Institute of Ecology (NIOO-KNAW). The visit included a tour, an introduction to NIOO's three major research themes, and a number of hands-on ecological measurements and experiments in which the King took part.