Photo: DEEP

After an hour's conversation with Sara Rydberg, you get a multifaceted picture of her, to say the least: a chemical engineer who became a plant physiologist, a natural scientist who collaborates with medical doctors, a botanist who is director of studies for environmental scientists and marine biologists, and a plant lover who likes animals a lot. How did this happen?

From chemical engineer to botanist

Sara grew up in Småland and chose to study in Växjö. She invested in a three-year course as a chemical engineer and as a recent graduate she got a job at a treatment plant. It only took six months before she realized that it was absolutely not her thing.

Then she began to think about what had been the most fun during the education and concluded that it was the biological part, above all biochemistry. Fortunately, the University of Växjö had a collaboration with Stockholm University which made it possible for Sara to continue her studies here. So she packed up and moved to Stockholm to immerse herself in biochemistry.

Botany entered her life when she found a course that dealt with the biochemistry and biology of plants. She got stuck at the Department of Botany, where they not only researched eukaryotic plants but also cyanobacteria. Sara became interested in the physiology of cyanobacteria in the Baltic Sea and the result was both a degree project and a doctoral thesis. After her defense in 2006, she was immediately offered to join another research group at the department, and soon she received her own grants and was able to form her own group. That's how it went and Sara has never left Stockholm University since she came here some 25 years ago. "It's my second home and my second family," she says.

Neurotoxic substances in phytoplankton

Sara's research group studies neurotoxins from phytoplankton. Most people know that you should be careful when the summer's alluring bathing water is filled with blooming cyanobacteria¸ because they can secrete toxic substances that cause skin irritations, intestinal problems and other acute symptoms.

But it is not these toxins that Sara's group is studying but two neurotoxins called beta-N-methylamino-L-alanine (BMAA) and 2,4-diaminobutyric acid (DAB). They were first discovered in cyanobacteria, but now it is known that they can also be formed by other phytoplankton organisms such as diatoms and dinoflagellates, and in larger quantities than by cyanobacteria. In Sara's group, they mostly work with diatoms, which are also fairly easy to grow in the lab.

BMAA and DAB are thus neurotoxic and have been linked to both Alzheimer's disease and ALS. But it is not an easy matter to demonstrate direct causal relationships between substances that are so difficult to measure and diseases that develop over such a long period of time. That the toxins can be formed by ordinary organisms in both brackish and salt water is in any case worrying, especially as the toxins can accumulate in water filtering organisms such as mussels.

Sara's group is happy to leave it to the medics to delve into the toxins' effects on humans. The group rather focuses on how the toxins are formed and what biological function they have. One might think that they constitute a defense against predation, but they probably function instead as signaling substances that regulate the growth of algae populations and the toxic effect is "an accident at work".

It is not often that Sara has time to go out to the lab these days; the fact is that it is so rare that it causes a stir when she puts on a lab coat. But she is reluctant to let go of sampling and other fieldwork, she prioritizes that highly, and it is placed both in the Baltic Sea (Askö) and in Mälaren and Hjälmaren.

The diatom Phaeodactylum tricornutum imaged in a scanning electron microscope. Photo: Sara Rydberg.

Teaching and directorship of studies

Sara teaches at all levels, from orientation courses to graduate school. Teaching an orientation course like Garden Biology is great fun, says Sara, the students are passionate about the subject and just want to hear more and more. Teaching the undergraduate plant physiology course is more of an uphill battle - it takes time for students to understand how cool plants are.

Sara has been director of studies ever since DEEP was formed in 2013. At first she was director of studies only for plant physiology, but a few years ago she was given more comprehensive tasks such as planning the staffing of all the department's courses. DEEP has an impressive range of subjects, so it was hard work but also educational to familiarize yourself with all the courses and it was fun to get to know all the employees. At that time, the subject specific Director of Studies still remained, but now they have been "dismantled" so Sara is the only Director of Studies at the entire DEEP (but with Johan Eklöf as deputy principal of studies and an important sounding board).

Can we expect proposals for exciting new courses from DEEP? Yes, of course we have ideas, says Sara, but that discussion is carried out in program councils and program colleges, they are the ones who decide what types of courses are needed to strengthen our various programs. The director of studies' role is to facilitate the process and be an intermediary link between DEEP and BIG.

Leisure time with children and animals

Teaching, research, head of studies job and a large family with three children who have to be shuttled here and there. It will be full days! But Sara finds recovery on horseback, preferably in fast-paced jumping. Then there is no job and no family, she says, then there is only me and the horse.

In time, there will probably also be a dog in the house, because Sara grew up with dogs. The home in Täby is close to the Roslagsleden and the family walks a lot in the forest, so that dog would be fine.