Flemish scientist leads the field in the exotic world of diatoms

In January, he took part in a Spanish expedition, aiming to stay for two weeks on Deception Island, one of the safest harbours in Antarctica. Curious about Van de Vijver’s experience, we got in touch with him just after his boat moored in Ushuaia – the gateway to the Antarctic in the southern tip of Argentina.

It turns out the trip didn’t go entirely as planned: To begin with, bad weather kept them at the airport at Punta Arenas in Chile. “It took us three attempts to land at the Chilean base on Antarctica,” he says, “and, once we were there, the Chilean navy held us on a boat for three more days, for various logistical reasons. So when we finally reached Deception Island, there were only three days left. I had to cram my planned schedule of nine fieldwork days into only three.”

Once they were in, the weather continued to hinder them. “My Czech colleague, Kate Kopalová, and I had to work amid strong winds and lashing rain.”

The general question that scientists like Van de Vijver are trying to answer is what diatoms actually are. And are they found literally everywhere, as many scientists believe? Or do they have a specific range of distribution, just like macro-organisms such as plants and animals?

“By collecting material from different islands with a more or less untouched ecosystem,” says Van de Vijver, “we hope to learn more about their distribution. We collect material that’s both alive and dead. The dead skeletons we use to study the different species morphologically; the living organisms we try to bring home safely, where we grow them in our laboratory so we can study their genetic diversity.”

That’s not possible, he continues, “in the neighbourhood of, for example, the port of Antwerp. Seagoing vessels carry tons of ballast water by which marine diatom species are distributed around the world. So when you find something unusual in the water of the Scheldt, you can’t be sure if it originated there. I once found a species in the port whose closest relatives are normally only found in the Indian Ocean.”

The diatom’s skeletons have weird and wonderful shapes and patterns, but scientists, he admits, don’t really know for what purpose. “I don’t have a clue,” Van de Vijver admits. “Every day I’m stunned by the incredible variety of shapes, forms and patterns that they possess. For the shapes, however, I can make a guess. All plankton needs to be very buoyant, so they require some necessary structures. Some epiphyte species – species that live on water plants – look like little curved knots. So they can attach themselves easily to reed canes.”

It’s the additional patterns that most skeletons are decorated with that make them look like little jewels, he says. “I suppose there’s some mathematics in it, as fractals are found in many more forms in the biological world. Thanks to these patterns, working with diatoms is a daily source of joy and admiration.”