WP 5

Variability of marine protists in the context of eddy dynamics


Work Package Leaders


Protists are a main pillar in the biological component of the oceanic carbon system.  The aim of WP5 is to investigate the direct influence of eddies on the structure of protist plankton communities (PPGs) and their consequences for the biological carbon budget. The obtained data will then be considered for an overall model of the oceanic carbon budget, which will contribute to a better understanding of eddy-driven coupling of physical, biogeochemical and biological processes. This will help to decipher the role of eddies, in particular with respect to their carbon source/sink function and for the biological carbon pump in coastal upwelling areas. Since coastal upwelling areas are extremely productive (e.g. fisheries) and thus substantially support socioeconomic aspects of neighbouring countries, it is highly relevant to gain a solid understanding of the function and functioning of such habitats. This enables predictions of changes in such habitats and the resulting economic consequences of climate change.


General Questions and Research topics

  • Functional and structural response of protistan plankton communities on eddy-dynamics in an Eastern Boundary Upwelling System
  • High-throughput amplicon sequencing will be used to reveal the structures of protistan plankton communities in cross-sections of different eddy systems in surface waters and in deeper water layers
  • Ship-board grazing experiments will be employed to assess the carbon-transfer from bacteria to protists as major components of the planktonic microbial loop
  • Lab experiments will be conducted to assess the effect of (deep) water-mixing on protistan plankton community structures and their bacterial carbon-uptake
  • With integration of data from other work packages, the carbon budget of the complete microbial loop and its potential for carbon transfer to higher trophic levels will be modeled


Figure 1 A. Fluorescence microscopy image of two heterotrophic ciliates with ingested food tracers (in green). Blue color visualizes the nucleus of the cells (stained with DAPI). Figure 1 B. Fluorescence microscopy image of a mixotrophic ciliate  with ingested food tracers (in green). Red color comes from autofluorescence of chlorophyll of symbiotic algae inside the ciliate, which make the ciliate independent of prey organisms under optimal light conditions. Cells are approx. 150 µm in length. Credit and copyright of both pictures: Sven Katzenmeier, Ecology Group, Technische Universität Kaiserslautern.




Thorsten Stoeck