With an estimated number of species ranging up to 100,000, diatoms are the most diverse group of algae, and one of the most diverse groups of eukaryotes, on Earth. When I first examined a diatom assemblage through a microscope, I became intrigued by their tremendous diversity. Ever since, my research has been driven by this interest to better understand diatom diversity, evolution, and biogeography.
Most of my research falls in the following four categories:
Most of my research falls in the following four categories:
The biogeography and evolutionary history of protists, through the lens of diatoms
What are the geographic distributions of protists and what drives these distributions? How common are endemic protist species? Do protist show global-scale biogeographical patterns similar to those of plants and animals? How do biogeographical patterns differ between marine and non-marine environments? How did past paleoclimate and geological events impact protist biogeography? These are some of the questions I aim to unravel using a combination of fossil sediment cores, molecular phylogenetics, and environmental DNA. During my PhD thesis, which I completed at Ghent University and Meise Botanic Garden, this has resulted in the discovery that Antarctic lacustrine diatom communities have been heavily impacted by past climate change, resulting in widespread extinction. In another study, I discovered that the diatom species complex (= groups of closely related species with highly similar or identical morphologies) surrounding the soil-dwelling diatom Pinnularia borealis are much more diverse than previously thought, and show complex biogeographical patterns suggestive of allopatric speciation. In the upcoming years, I aim to expand upon these research lines by using population genomics and ancient DNA to further unravel the drivers behind speciation and biogeographical structuring in diatoms.
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I am using the soil-dwelling diatom species complex Pinnularia borealis as a model system to understand global biogeographical patterns in non-marine diatoms.
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Population structure and the genetic basis for microbial adaptation to novel environments
How do protists adapt to their environment? To this day, the answer to this question remains elusive, yet it is essential for making predictions on how protists, which perform essential ecosystem functioning such as primary production and biogeochemical cycling, will be impacted by environmental change. Most of what we know about protist adaptation comes from growth experiments on ‘model strains’. Yet, such studies provide only limited insight into the adaptive process, since adaptation is ultimately a genetic process. To tackle this critical knowledge gap, I am currently using population genomics to unravel the genetic basis of protist adaptation, using the natural colonization of the ancestrally marine diatom Skeletonema marinoi of the brackish Baltic Sea as a model system. Furthermore, I aim to expand this research line to answer exciting outstanding questions regarding adaptive processes across the diatom tree of life. Get in touch if you are interested!
How do protists adapt to their environment? To this day, the answer to this question remains elusive, yet it is essential for making predictions on how protists, which perform essential ecosystem functioning such as primary production and biogeochemical cycling, will be impacted by environmental change. Most of what we know about protist adaptation comes from growth experiments on ‘model strains’. Yet, such studies provide only limited insight into the adaptive process, since adaptation is ultimately a genetic process. To tackle this critical knowledge gap, I am currently using population genomics to unravel the genetic basis of protist adaptation, using the natural colonization of the ancestrally marine diatom Skeletonema marinoi of the brackish Baltic Sea as a model system. Furthermore, I aim to expand this research line to answer exciting outstanding questions regarding adaptive processes across the diatom tree of life. Get in touch if you are interested!
Unravelling how diatoms mitigate stress and achieve acclimation to environmental shifts
The persistence of a population during episodes of environmental change, or when colonizing a new habitat, hinges initially on the ability to survive a suite of physiological stressors and later by the ability to adapt to the new environment. In other words: to allow for adaptation, the organism has to leverage a successful stress-response followed by long-term acclimation and adaptation. Yet, little is known about the ways that protists, including diatoms, mitigate stress and acclimate to their environment. To tackle this knowledge gap, I have been using transcriptome sequencing (RNA-seq) on stressed and acclimated diatom cultures from various species to gain detailed insights into their response to environmental shifts. This resulted in the discovery that marine diatoms show high levels of intraspecific variation in their acclimated response to low salinity, and that the genes involved in mitigating acute salinity stress are vastly different from those that allow for long-term acclimation. And there is more to come!
The persistence of a population during episodes of environmental change, or when colonizing a new habitat, hinges initially on the ability to survive a suite of physiological stressors and later by the ability to adapt to the new environment. In other words: to allow for adaptation, the organism has to leverage a successful stress-response followed by long-term acclimation and adaptation. Yet, little is known about the ways that protists, including diatoms, mitigate stress and acclimate to their environment. To tackle this knowledge gap, I have been using transcriptome sequencing (RNA-seq) on stressed and acclimated diatom cultures from various species to gain detailed insights into their response to environmental shifts. This resulted in the discovery that marine diatoms show high levels of intraspecific variation in their acclimated response to low salinity, and that the genes involved in mitigating acute salinity stress are vastly different from those that allow for long-term acclimation. And there is more to come!
Describing the unknown: adventures into diatom taxonomy
Throughout my MSc thesis, which I completed at the University of Antwerp and Meise Botanic Garden, I received a thorough training into diatom taxonomy using morphological techniques. I consider this training to be one of my main strengths when it comes to building a research career that aims to understand the diversity of diatoms. Even though I am mostly working with genome and transcriptome datasets these days, my past training ensures I never lose sight of the organism, have a thorough understanding of diatom community assembly, and am not afraid to question long-standing species boundaries whenever my data indicate presence of cryptic diversity. And whenever I get the chance, I will describe the odd new diatom species with great enthusiasm! Over the years, this has led to the description of Pinnularia catenaborealis, Pinnularia subcatenaborealis, Achnanthidium digitatum, Achnanthidium petuniabuktianum, and Gomphonema svalbardense, as well as the typification of Pinnularia rabenhorstii.
Throughout my MSc thesis, which I completed at the University of Antwerp and Meise Botanic Garden, I received a thorough training into diatom taxonomy using morphological techniques. I consider this training to be one of my main strengths when it comes to building a research career that aims to understand the diversity of diatoms. Even though I am mostly working with genome and transcriptome datasets these days, my past training ensures I never lose sight of the organism, have a thorough understanding of diatom community assembly, and am not afraid to question long-standing species boundaries whenever my data indicate presence of cryptic diversity. And whenever I get the chance, I will describe the odd new diatom species with great enthusiasm! Over the years, this has led to the description of Pinnularia catenaborealis, Pinnularia subcatenaborealis, Achnanthidium digitatum, Achnanthidium petuniabuktianum, and Gomphonema svalbardense, as well as the typification of Pinnularia rabenhorstii.