In Search of Algae on the Other Side of the Globe

In 2010, about 150 junior researchers applied for an Ambizione grant with the Swiss National Science Foundation. Only a third of the research projects made the grade. One of them was by Rixt de Jong, a postdoc researcher at the Oeschger Centre for Climate Change Research. She aims to reconstruct climate in Chile.

The tool Rixt de Jong currently uses to prepare for her new research project may seem unexpected for a climate researcher: Google Earth. She searches for lakes in the South of Chile. Not just any lakes, but those that are suitable for the new research project that received the Ambizione grant. That project aims to reconstruct temperatures over the past thousand years, based on climatic information stored in lake sediments.

The knowledge that one's research is supported for the next three years is encouraging for any researcher. What Rixt de Jong is particularly happy with is the research itself: "At one point a researcher should get the chance to continue a chosen line of research and invest in it."

Scientific New Start

Rixt de Jong switched research topics several times during her career. The young woman from the Netherlands studied physical geography and geology at Utrecht University and was an exchange student at Trinity College in Dublin. She then moved to Sweden to obtain her PhD at Lund University. Tracking and reconstructing long-term climate and land use changes were her new areas of expertise. During the NCCR Climate Summer School in Grindelwald, she met Martin Grosjean, managing director of the Oeschger Centre and professor for geography at the University of Bern. Rixt de Jong was fascinated by just how precise researchers in Bern are aiming to reconstruct climate. "In my thesis, I worked on a time scale of 6,000 years. You use proxy data, but you don't exactly know how well these proxies actually reflect past climates. If you work with age uncertainties of a hundred years, a lot becomes uncertain. For me, my main interest now lies in understanding climatic processes and how climate may be reflected in the proxy-methods we use."

With her dissertation and an EU grant in her pocket, Rixt de Jong joined Martin Grosjeans group for Lake Sediment and Paleolimnology research at the Oeschger Centre. The postdoc admits, with a grin, that it were not only the scientific perspectives that drew her to Bern: the nearby mountains were also particularly appealing to the keen skier and climber from Europe's flattest country. In the laboratory at Erlachstrasse, the 31-year-old once more had to make herself familiar with new research methods. "It has taken me about two years to learn the methodology based on microfossils of the golden brown algae (chrysophyte stomatocysts) as climate indicators."

Bernese Pioneer in Chile

It is no coincidence that Rixt de Jong chose to conduct her research in Chile. Martin Grosjean's group belongs to the pioneers of climate reconstruction in the south-central Andes. The junior researcher will therefore benefit from a local network as well as from previous work by the group. Still, her project is highly ambitious. To obtain accurate temperature reconstructions, Rixt de Jong will analyze sediment cores collected from two or three lakes in the south of Chile. First, however, she must refine the method based on the golden-brown algae. To know which conclusions can be drawn from the fossil algae in the lake sediments, she has to understand how sensitive today's golden algae are to temperature. She therefore plans to take samples in 40 to 50 lakes at different altitudes, from zero to 2,500 meters (8,200 feet) above sea level. She uses so-called sediment traps to collect the algae in each lake, and compares these to measured temperatures to find out their temperature tolerance range and optima.

For the next three years, Rixt de Jong will face many new challenges – for example, she has never yet been to the country where she'll conduct her extensive field studies. And where will she go from there? Will she pursue an academic career? "Yes, I could see myself doing that! In addition to my research, I also enjoy mentoring students and I like teaching; being a professor or lecturer includes all these aspects". Despite her aspirations, Rixt de Jong is not prepared to sacrifice everything for her career. "A permanent move to a different continent, for example", she sais, smiling, "is not really an option."


(Rixt de Jong has left the Oeschger Centre in 2014)