Just for fun, Sandra Brügger has calculated the number of pollen grains and spores that she’s counted over the course of her dissertation: nearly 1.8 million within four years, a dizzying figure. Imagine looking for a grain of pollen on a microscope slide. Adjusting the microscope. Identifying the grain’s plant species. Hitting a button to count it. Over and over again. 1,800,000 times. Today, the climate scientist can recognize 400 different types of pollen at a glance and says, “Pollen analysis is indeed a special area. Sometimes I kept counting as I fell asleep at night.”
Sandra Brügger never thought that being a researcher — which of course involves more than counting pollen — would be so much fun. “I wasn’t that into science until my master’s thesis,” she confesses in the break room of an old brick building at the Institute of Plant Sciences, just a stone’s throw from the Botanical Garden.
Field research in the Amazon
But while looking for a topic for her master’s thesis she found the perfect project: Fieldwork at the Geographic Institute of Bolivia. This promised an adventure and new horizons. Goal: Using a sediment core from Lago Rogaguado, a large lake in the Amazon region, to figure out the region’s vegetation history. While evaluating data from this natural environmental archive, the student discovered some amazing findings that were even published in a respected journal. Thanks to the corn pollen she found in the sediment layers, she was able to prove that there had been agriculture in the Amazon region 6,500 years ago already — much earlier than previously thought.
This sparked Sandra Brügger’s interest in research. Definitely. All the more so when she encountered new challenges in the research group of paleoecologist Willy Tinner, from whom she had learned about using pollen as a marker of past environmental and climate changes. It was a large project, financed by the Swiss National Science Foundation and called “Paleo fires from high-alpine ice cores”. The interdisciplinary project wanted to use ice cores to reconstruct the history of forest fires in four regions around the world, plus get a picture of the the vegetation dynamics and early agricultural activities in these areas — the part of the project that Sandra Brügger would end up doing her dissertation on.
Now she was working with glacial ice rather than sediments from the bottom of a tropical lake. Ice cores are considered excellent environmental and climate archives, since the ice layers store elements such as charcoal particles, soot and pollen quite well, thus enabling researchers to date them very precisely. Apart from that, “The pollen grains are beautifully preserved in the ice.”