The secret lives of microbes

Many scientists believe that the scientific approach to understanding and manipulating (in its neutral meaning: acting upon, utilising) the non-living and living world is the only one possible. No doubt it is a necessary one and it provides a solid basis for policy decisions. But our perspectives on nature, life, human and other beings derive from other sources as well. Why we marry one person instead of another one, why we have different associations with yellow in contrast to red, cannot be explained by neurosciences or by knowing the different wavelengths of yellow and red light. Erwin Schrödinger, one of the co-founders of quantum mechanics, has written cogently about this in two booklets, “What is life” of 1944, and particularly “Mind and matter” of 1956. Art in its various manifestations provides a kaleidoscopic range of complementary perspectives.
EuroScience has recognized this since long. As of ESOF2006 in Munich the “Science and Poetry” session has been a gem in the ESOF programmes. And many events in the “Science in the City” track of ESOF illustrate the multiple interfaces between science and the arts. That is why we also make room in EuroScientist for articles about these interfaces.

By EuroScientist team

Scientists inspire artists – and vice versa – in S.E.A. project

In the unique Sea Encounters Art (S.E.A.) project on the Dutch island Texel, marine scientists cooperate with artists. The result is exhibited this summer on various locations on the island. One of the ‘science-art-couples’ are microbiologist Henk Bolhuis and micro-photographer Wim van Egmond. Their BIOFILM project shows fascinating time-lapse images of microbial life, in which cyanobacteria play the lead role.

“These are the real extremophiles”, says molecular microbiologist Henk Bolhuis, and he points at a muddy green-brownish coloured soup in a little glass jar in his laboratory at the Netherlands Institute for Sea Research, based on the Dutch island of Texel. The muddy jar contains a rich collection of microbes, collected from ‘microbial mats’ on several beaches in the Wadden Sea.

Fossil record

These organisms can been seen as extremophiles since they can survive extreme fluctuations in physical conditions, such as temperature, salinity and humidity. Hundreds of different species of microbes are found in microbial mats; using molecular techniques, Bolhuis even found 2000 species in the top 5 mm soil of mudflats.

Microbial mats are also known (and famous) from the fossil record by the name of ‘stromatolites’, rocks made by single-celled organisms that were able to catch sediment in their web of sugars and glycoproteins. The typical round shape of stromatolites is caused by erosion. Bolhuis: “The microbial mats which we find on the beaches in the Wadden Sea are often named ‘algal mats’. However, this is incorrect, as one of the dominant species in these mats are cyanobacteria. Bacteria don’t possess a nucleus, algae do.”

Cyanobacteria can be regarded as the “forests of the oceans”. The protective ozone shield – which made life on land possible – exists thanks to the abundance of oxygen, produced by cyanobacteria since 3.5 billion years. © Wim van Egmond

Diet of sunlight

It soon becomes clear that not only microbiologists are working in this lab, as many cameras are set up to picture the biotopes in the cubic glass jars. This rich microbial life – on a diet of sunlight – turns out to play the lead role in the Sea Encounters Art project, in which scientists and artists work closely together. Bolhuis, his near colleague Michele Grego and Wim van Egmond make up the BIOFILM-team. Grego specializes in the cultivation of microbes; Van Egmond is a micro-photographer specializing in picturing the microbial world by magnifying the images in an artistic way.

Bolhuis and Van Egmond have chosen to make the microbes from the mudflats visible and added the element of time by creating time-lapse films from thousands of photographs. The result is fascinating. By compressing weeks or months in a few minutes, we are able to see dynamic microbial communities.

Compressed time

These time-lapse films, without a beginning or end, show the organisms in in their continuous activity: moving, searching for food, producing gases, growing, extending from or withdrawing in the sand and silt.

Photographic (static) images were taken on average every 15 minutes, 24/7, for about nine months, in the NIOZ lab. Ten cameras were set up; 1500 photographs (25 images per sec.) make up 1 minute of film and 6 minutes of film covers about three months time. The result is breath-taking and opens up a new, colourful world to the public, but to scientists as well, as they normally don’t see the cyclical activity of microbes, compressed in a couple of minutes.

Surprising bacterial ‘behaviour’

Bolhuis, an experienced marine microbiologist, noticed behaviour of these single-celled organisms that he never saw before. “What surprised me most, were the little ‘knots’ the Beggiatoa – a species of sulphur loving bacteria – produce. It might be something related to exchange of DNA or nutrients, but we just don’t know.” (See featured image at the top.)

Another fascinating aspect that Van Egmond made visible using his time-lapse images is the cycle of day and night: white microbes oxidizing sulphur (from H2S) move up and down in the water right above the sediment, depending on the presence of oxygen (produced by cyanobacteria). “Here we see ‘symbiosis at a distance’ among the various species of sulphur bacteria”, Bolhuis says.

Tough little worms

“What surprised me most are these tough little worms, which I thought were flatworms but belong to a different more ancient group, the Acoelomorpha, we saw in BIOFILM”, says Van Egmond. They seem to survive anoxic conditions for quite a while.”

At the edge of water and sediment live millions of microscopic creatures, invisible to the human eye, such as Acoelomorpha. © Wim van Egmond

It made him think about ‘deep time’ at the start of the Archean eon, before oxygen gas was even present on Earth, long before photosynthesis was ‘invented’. The process of photosynthesis is even invented by cyanobacteria. In fact, the part of the plant and algal cell in which photosynthesis takes place, the chloroplasts, are descendants of cyanobacteria that became incorporated in plants and algae in the course of evolution. That’s why Van Egmonds gave cyanobacteria a lead role in BIOFILM.

“Cyanobacteria are an underestimated species of micro-organisms in their role they play on Earth”, he says. “Usually we hear of them in the news in relation to toxic swimming water on a hot summer day, as cyanobacterial blooms can result in a depletion of oxygen in the water and a release of toxins. But their role is far more important as oxygen producers and they can be considered as the forests of the oceans”.

19th century science and digital photography

“In modern times, science is less visual”, Van Egmond says. “Nowadays, biological research focuses on DNA-scale. Therefore, my work is more related to 19th century scientists. I use old fashioned techniques but combine them with the modern possibilities of modern digital photography.

And that’s where the S.E.A. project is all about. The main goal is that scientists and artists inspire each other, to create new ideas and visions. Bolhuis: “We decided to continue this project, because we observed unexpected behaviour in bacteria. In the future, I like to work together with artists more often, as it inspires to see our scientific work in an unexpected way, creating new and unforeseen questions.”

Three colours dominate at the edge of sand/silt and water: green (cyanobacteria), brown (diatoms) and white and pink (sulphur-loving bacteria). © Wim van Egmond

The BIOFILM exhibition is presented to the public in the visitors centre Ecomare on the island of Texel. BIOFILM is one out of ten projects in the Science Encounters Art (S.E.A.) project, a result of an intensive cooperation between marine researchers and artists. Other projects cover e.g. plastic waste, structure of sand grains, seaweed as a new raw material for bio-plastic and bird research about migrating knots.

The northern fulmar is depicted as a symbol of the ‘plastic virus’. ’Noordse Stormvogel’ is another project in Science Encounters Art. © Annemieke van Roekel

Further reading
–  Cardoso D.C., Cretoiu M.S., Stal L.J. & Bolhuis H. (2019) Seasonal development of a coastal microbial mat. Scientific Reports 9: 9035. Direct link:
–  Hornlein C., Confurius-Guns V., Stal L.J. & Bolhuis H. (2018) Daily rhythmicity in coastal microbial mats. NPJ biofilms and microbiomes 4: 11. Direct link:

Featured image credit: The enigmatic ‘knots’ produced by Beggiatoa. © Wim van Egmond

Annemieke van Roekel

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.