Dr. Susanne Dunker Dr. Susanne Dunker     Dr. Susanne Dunker

Contact


Department for Physiological Diversity
German Center for Integrative Biodiversity Research (iDiv)
Deutscher Platz 5e
04103 Leipzig
Germany

phone: +49 341 9733170
e-mail: susanne.dunker@ufz.de



Orcid

Researchgate




Research interest

My research interests are strongly influenced by the time of my diploma thesis, where I dealt with a hypertrophic lake in Leipzig. In this lake cyanobacterial blooms and fish kill occurred. I am fascinated by the fact that although a lake contains extensive nutrients, during the phase of cyanobacterial blooms, diversity of other phytoplankton species is very low. I want to gain insights into which factors make it possible that diversity is suppressed and reversed, under which circumstances diversity can be supported.


Executive Summary

Phytoplankton organisms are ideal candidates to study diversity due to their fast growth. These organisms are microscopic small but have an enormous impact on the water quality and ecology. Their ability to convert light energy to biomass via photosynthesis determines the extent of primary production. The efficiency of this conversion (numbers of photons needed to assimilate one molecule of carbon) is an important trait for physiological activity and highly varies within taxonomic groups (e.g. cyanobacteria, green algae, dinophytes, cryptophytes and diatoms). This means that the same quantity of light not necessarily leads to the same productivity for different taxa. Until now, it was not possible to investigate the respective energy use efficiency of different taxa in a complex community. The aim of my PhD-thesis was to use cellular characteristics to resolve the energy use efficiency for different species in a mixed culture.

Phytoplankton species can be distinguished due to their different pigmentation patterns by the means of flow cytometry. Flow cytometry delivered the following cellular traits: cell volume, dry weight and chl a-content per cell and also the variability of these traits within a population. These data allowed the quantification of absorbed light energy in relation to assimilated biomass separately for different species in a mixed culture. I could show that energy use efficiency differed between mono-culture- and co-culture-conditions in a species-specific manner. This means that co-cultivation could be less productive in comparison to the mono-cultures because within the co-culture one species had a lower energy-use-efficiency.

With this work I demonstrated, how energy is distributed and converted to biomass in a phytoplankton community. Furthermore, a model system for competition experiments was established (Dunker et al. 2013). Now it is possible to consider aspects like different cell size, the influence of nutrient-concentrations or different defense traits like morphological and chemical defense with regard to the outcome of competition. It is also possible to examine multi-species experiments if the used species differ enough in their pigmentation to guarantee a fast identification by flow cytometry.

Flow cytometric discrimination of four phytoplankton species.
04/2015 - present present Post-Doc at UFZ (Helmholtz centre for environmental research)/ iDiv (German Centre for Integrative Biodiversity Research) Leipzig, Germany
10/2013 - 03/2015 Post-Doc at the University of Leipzig (“Plant Physiology”), Germany
12/2008 - 07/2013 PhD thesis at the University of Leipzig, Germany
Institute of Biology, Department: “Plant Physiology”
Title: “Dynamic of phytoplankton under hypertrophic conditions”
Supervisor: Prof. Dr. C. Wilhelm
10/2003 - 10/2008 Study of Biology (University of Leipzig, Germany)

Index:

2018 (1)
2017 (1)
2016 (1)

You could use our publication index for further requests.

2018 (1)

  • Dunker, S., Wilhelm, C., (2018):
    Cell wall structure of coccoid green algae as an important trade-off between biotic interference mechanisms and multidimensional cell growth
    Front. Microbiol. 9 , art. 719
    full text (url)
to index

2017 (1)

  • Dunker, S., Althammer, J., Pohnert, G., Wilhelm, C., (2017):
    A fateful meeting of two phytoplankton species—Chemical vs. cell-cell-interactions in co-cultures of the green algae Oocystis marsonii and the cyanobacterium Microcystis aeruginosa
    Microb. Ecol. 74 (1), 22 - 32
    full text (url)
to index

2016 (1)

  • Dunker, S., Nadrowski, K., Jakob, T., Kasprzak, P., Becker, A., Langner, U., Kunath, C., Harpole, S., Wilhelm, C., (2016):
    Assessing in situ dominance pattern of phytoplankton classes by dominance analysis as a proxy for realized niches
    Harmful Algae 58 , 74 - 84
    full text (url)
to index


Articles

  • Dunker, S. (2014): The Cell Biology of Cyanobacteria, E. Flores, A. Herrero (Eds.). Caister Academic Press, Norfolk, UK (2014), Book review on: 308 pp., GBP 159.00, USD 319.00, ISBN: 978-1-908230-38-6, Journal of Plant Physiology, Vol. 171 (16): 1453
  • Lentendu, G., Hübschmann T., Müller S., Dunker S., Buscot F., Wilhelm C. (2013) Recovery of soil unicellular eukaryotes: an efficiency and activity analysis on the single cell level. Journal of Microbiological Methods, Vol. 95 (3):463-469
  • Dunker, S., Jakob, T., Wilhelm, C. (2013) Contrasting effects on the growth of two green algae (Oocystis marssonii, Scenedesmus obliquus) during cocultivation with Microcystis aeruginosa revealed by flow cytometry. Freshwater Biology, Vol. 58: 1573-1587
  • Wagner, H., Dunker, S., Liu, Z., Wilhelm, C. (2013) Subcommunity FTIR to determine physiological cell states. Current Opinion in Biotechnology 24 (1): 88-94

Oral Presentations

  • Dunker, S. (2010) „Flow cytometry for phytoplankton analysis with taxonomic resolution“, Meeting of the German Society for Cytometry, Leipzig
  • Dunker, S. (2012) “The influence of interspecific effects on phytoplankton primary production”, Meeting of Plant Physiologists of Saxony, Saxony-Anhalt and Thuringia, Jena
  • Dunker, S. (2012) “Interspecific effects on growth and primary production in mixed culture of the green algae O. marssonii and the cyanobacterium M. aeruginosa”, Meeting of the Phycology Section of the German Botanical Society, Wuppertal
  • Dunker, S.; Jakob, T.; Nadrowski, K., Wilhelm, C. (2013) „Distinctive habitat preferences for major phytoplankton groups in a hypertrophic lake“, Meeting of the German Society for Limnology, Potsdam

Poster

  • Dunker, S., Wilhelm, C. (2009) “Co-cultivation of algae and effects on their growth and physiology”, Meeting of the German Botanical Society Leipzig
  • Dunker, S., Liu, Z., Nadrowski, K., Wilhelm, C. (2011) „Taxonomisch aufgelöste Biomassemodellierung von Phytoplankton“, Meeting of the German Society for Limnology, Freising
  • Dunker, S., Wilhelm, C. (2011) “Comparative study of mono-culture and mixed culture of the green algae Oocystis marssonii and the cyanobacterium Microcystis aeruginosa”, Meeting of the German Botanical Society, Berlin
  • Dunker, S., Jakob, T. Wilhelm, C. (2014) „Quantification of co-cultivation effects on phytoplankton species“, Meeting of the Phycology Section of the German Botanical Society, Stralsund

PhD thesis

  • Dunker, S. (2013) Phytoplankton dynamic under hypertrophic conditions, University of Leipzig, Department of Plant Physiology

Diploma thesis

  • Dunker, S. (2008) “Estimation of Chl a-specific absorption coefficient of phytoplankton on taxon level”, University of Leipzig, Institute of Biology, Department of Plant Physiology

Reviewer activities

  • Aquatic Microbial Ecology
  • Current Microbiology
  • Critical Reviews in Biotechnology
  • Cytometry Part A
  • Ecology
  • Ecology and Evolution
  • Ecotoxicology
  • Freshwater Biology
  • Journal of Applied Ecology
  • Journal of Plant Physiology
  • NSF
  • Scientific Reports
  • WATER

Memberships

  • Member of German Society for Cytometry (DGfZ)
  • Member of German Society for Limnology (DGL)
  • Member of German Society for Phycology


  • PolDiv (Automated high throughput pollen diversity monitoring of air quality and pollination as ecosystem services)
  • Ecometeor platform (https://www.idiv.de/research/platforms_and_networks/ecometeor.html)
  • Biodiversity provisioning resilience along environmental gradients