Prøveforelesning og disputas Master of Research in Advanced Biological Sciences Scarlett Zetter

Later, at 12.15 she will defend her thesis entitled:

"Echoes of the Past: Finding the Secrets of Ancient Ecosystems using SedaDNA"

Department leader at the Department at the Arctic University Museum of Norway Geir Rudolfsen will lead the disputation.

Popular Science Summary:
Lake sediments build over time as surrounding materials wash in, preserving a record in chronological order. From these, we can extract and sequence DNA of ancient plants and mammals to reconstruct past ecosystems. While plant DNA could be identified to species level, mammal DNA was harder. We needed to improve existing method by blocking human DNA so we could sequence other mammal DNA. Using these new methods, we sequenced plant and mammal DNA from British sediments dated to 19-15 thousand years ago. We found that the UK was a cold, dry steppe-tundra, home to saxifrages, lemmings and later, mammoths. As temperatures rose, these species retreated to cold refuges, like the Alps. We then applied the same methods to sediments from Alpine lakes covering the last 12,000 years. We found before high-altitude grazing, the climate shaped plant diversity. Cattle grazing then became the main driver, increasing flowering plant richness. Therefore, to preserve alpine diversity, grazing is key.

Evaluation Committee:

• Researcher Dr Vivian Astrup Felde, University of Bergen (1. opponent)
• Associate Professor Johan Pansu, University of Lyon, France (2. opponent)
• Professor Ines Heiland, AMB (internal member and leader of the committee)

Supervisors:

• Professor Inger Greve Alsos, the Arctic University Museum of Norway
• Researcher Dr Peter Heinzman, Stockholm University, Sweden
• Senior researcher Dr Dorothee Ehrich, the Arctic University Museum of Norway
• Associate Professor Andreas Tribsch, University of Salzburg, Austria

Streaming:

Both the defense and the trial lecture will be streamed and recorded from UNIS:

• Trial lecture
• Disputation

Thesis:

The thesis is available through Munin