Aquatic microbial ecology · Biophysics
I study how bacteria live, move, and cooperate at the scale of a single cell — in the water of lakes and seas.
Newton Research Fellow, Queen Mary University of London — becoming a Lecturer and starting my own group in 2028. Previously a senior researcher at ETH Zurich.
I'm an experimental biophysicist and computational microbiologist. My work sits at the border between microbial ecology and microbial physiology: I want to understand why individual bacteria behave the way they do, and how those decisions — made cell by cell — add up to the structure and function of whole aquatic communities.
To watch this happen I use microfluidics and live single-cell microscopy, following bacteria one at a time as they swim, sense their surroundings, feed, and interact. It's a way of seeing behaviour that averaged, population-level measurements tend to hide.
What I work on
Swimming is powerful but costly. I study the motility, chemotaxis, and foraging of aquatic bacteria — how they navigate toward food and when it's worth the energy to do so. This led to a risk–reward trade-off that splits marine bacteria into distinct search strategies, and, more broadly, to a quantitative movement ecology of micro-organisms.
Bacteria rarely live alone. In my new work at Queen Mary I'm studying the interactions between a freshwater cyanobacterium and the heterotrophic bacteria that live alongside it — who feeds whom, who survives starvation, and how communities assemble from these encounters across lakes and seas.
Much of my work is about building the right instrument. I develop microfluidic "on-a-chip" devices and single-cell FRET imaging to observe living communities directly, and I use the physics of signalling networks — including near-critical cooperativity in the bacterial chemosensory array — to understand what cells can and can't sense.
Selected work
Risk–reward trade-off in motility endurance generates dichotomy in search strategies among copiotrophic marine bacteria Behind the paper: To swim or not to swim
Spontaneous switching in a protein signalling array reveals near-critical cooperativity Behind the paper: A critical sense of smell
Stochastic resilience enables particle foraging in oligotrophic environments
Path here
I trained as a physicist at Delft University of Technology before moving into biophysics for my PhD at the AMOLF institute in Amsterdam, where I built single-cell FRET methods to watch signalling inside individual bacteria.
As a postdoc and then senior researcher in Roman Stocker's Environmental Microfluidics group at ETH Zurich, I turned to the sea — using microfluidics to follow how marine bacteria find, colonise, and break down sinking particles, and how their motility shapes the communities that form. In August 2026 I joined Queen Mary University of London as a Newton Research Fellow, where my questions have broadened from the ocean to aquatic systems more generally, freshwater lakes included. From 2028 I'll continue there as a Lecturer, building my own group.
Away from the bench
Most of the world's population lives along a coast or close to a lake — we have always settled near water. These are my favourite water bodies, and each one connects back to the science.
I grew up a few kilometres from the North Sea, and what I miss most is its everlasting wind — and the herring, the one thing I still crave from the Netherlands. Almost everything else you notice on that coast is really microbes at work: the briny smell of the sea is mostly dimethyl sulfide, a gas made by marine microorganisms, and the foam whipped up in the surf is organic matter released by blooms of algae and bacteria.
The canal runs beside Queen Mary's Mile End campus and threads across the city, from Little Venice to the Thames at Limehouse. It's a favourite of runners and cyclists, a fine place to walk, and the commute route of a lucky few. I love it as an everyday piece of urban freshwater — a reminder that aquatic microbial life belongs to cities as much as to oceans.
Lake Zürich is an optimistic story. Through the twentieth century, phosphorus from the city's sewage and detergents tipped it into eutrophication — the deep water losing oxygen, and the cyanobacterium Planktothrix rubescens tinting autumn blooms a burgundy red. Switzerland's response — wastewater treatment across the whole catchment and cutting phosphate at the source — turned it around. Today it is clean enough to supply drinking water to hundreds of thousands of people, and clear enough to swim in from the middle of the city.
Photographs © Johannes Keegstra.
Get in touch
I'm always glad to talk about aquatic microbes and the questions behind this work. If your research touches on any of it, or you'd simply like to get in touch, do send a note.
Queen Mary University of London · School of Biological and Behavioural Sciences