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Arctic Seminar Series: Dynamics of phytoplankton populations measured by flow cytometry

Dr Gerrit van den Engh from Center for Marine Cytometry presents observations from Hawaii, Barents sea and the coast of Peru

2016.09.07 | Susanna Pakkasmaa

Date Thu 27 Oct
Time 14:00 15:00
Location ARC, Ny Munkegade 114, Building 1540, meeting room 1540-020. Roskilde I0.19

Gerrit van den Engh. Photo Institute for Systems Biology.

Dr Gerrit van den Engh from the Center for Marine Cytometry, Washington, USA, is visiting ARC in October. On Thursday 27 October he will give a seminar about Dynamics of phytoplankton populations measured by flow cytometry – Observations from Hawaii, Barents sea and the Oxygen Minimum Zone off the coast of Peru.

Flow cytometry, a technology originally developed for blood cell analysis, has been proven to be a useful tool for plankton analysis. Flow cytometers detect, inspect and measure every particle in a water sample, thus providing an accurate, quantitative census of its inhabitants.

Application of the technique has led to the discovery of Prochlorococcus, that is now recognized as one of the most abundant organisms in the tropical ocean but had not been detected by microscopy nor by any other technique. With the arrival of single-cell DNA technology, the measurement and separation of individual plankton particles has even become more important. Community-wide predictions of biochemical/ physiological activities in an ecosystem can now be predicted based on an inventory of particles and their expressed genes.

Despite the importance of flow analysis for the study of microbial communities, the instruments that are being used differ little from the versions designed for biomedical research. This, despite the fact that the physical properties of microbes and phytoplankton are very different from those of blood cells.

Ger van den Engh has spent the past 10 years adapting and optimizing flow cytometers for environmental plankton samples and have developed methods for integrating flow cytometry results with other environmental measurements.

Depth profiles generated in this manner show a surprising variation in plankton communities across even very small changes depth. Using examples from studies at a number of sites in the world, I will demonstrate that flow cytometric depth profiles are useful in understanding the factors that determine the composition and dynamics of plankton communities.

Arctic Research Centre