Department Systems Analysis, Integrated Assessment and Modelling

Critical dynamics in phytoplankton communities?

Phytoplankton consists of photosynthesizing algae and bacteria in oceans and lakes. They form the basis of the aquatic food chain and are responsible for about half of Earth’s total primary production. Even in our local waters, there are hundreds of species of phytoplankton. Many of these species are still unexplored and relatively little is known about their complex interplay. Under certain conditions, individual species can suddenly multiply en masse. Such algal blooms, for which there is no early warning system to this day, can present a danger to humans and animals. A better understanding of biodiversity and dynamics of phytoplankton is needed in order to predict its reaction to human induced environmental changes (global warming, nutrients, environmental toxins).

Content and objective of the research project
The overarching goal of this research project is to better understand the biodiversity and dynamics of phytoplankton in our lakes. Thanks to advanced laser technology, we now have an unprecedented wealth of information on phytoplankton. Automated flow cytometers on our lakes capture length, shape, pigmentation, etc. of millions of plankton particles with high temporal and spatial resolution. These records allow us for the first time to test theories about the composition and dynamics of phytoplankton in detail and thereby improve both our understanding and our ability to predict. In particular, we will use models for systems of interacting particles, which have been developed in physics. Physicists have been using such models for decades to understand collective phenomena in complex interacting particle systems. It turns out that many of these phenomena are remarkably universal and do not depend on details of the interactions.