Research Group Plankton – Competition and Interactions


We are interested, how plankton communities are structured by competition and feeding relationships and how the structure of plankton food webs changes through time in response to external drivers, such as season, global warming, ocean acidification, eutrophication and top-down cascading effects from fisheries.  

Plankton as a model system: We to study widely debated issues of theoretical and general community ecology, such as the roles of bottom-up vs. top-down forcing, the maintenance of biodiversity under competition pressure, the role of biodiversity for ecosystem functioning.

Ecological functions of plankton: We study, how Global Change influences the role of plankton for the nutritional basis of pelagic fish production, the role in carbon and nutrient cycling and in the formation of mid-water low oxygen zones.

In order to achieve our goals, we aim to combine experimental research in the lab and the field, ocean going field research, data mining, and modeling.

The Team

Ulrich Sommer
Helena Hauss
Juan-Carlos Molinero
Evangelia Charalampous
Kriste Makareviciute
  • Prof. Dr. Ulrich Sommer (Full Professor, Group Leader): experimental community ecologist
  • Dr. Helena Hauss (subproject B8 in the SFB 754; experimental and field analysis of the ecosystem function zooplankton in tropical oxygen minimum zone
  • Dr. Juan-Carlos Molinero fish (WP1 in OceanCertain;  analysis of long-term data series of climate, phytoplankton, zooplankton and
  • M.Sc. Evangelia Charalampous (DFG-priority program 1704 “Dynatrait”, subproject 'TraitHist'; role of phytoplankton traits for nutrient cycling, grazing and sedimentation
  • M.Sc. Kriste Makareviciute: (HOSST research school) - 'role of phytoplankton for the resilience of plankton food webs'


  • SFB 754 (Climate-Biogoechemistry Interactions in the Tropical Ocean; is a DFG-funded collaborative research center devoted to the dynamics of tropical oxygen minimum zones. Our subproject B8 studies the response and the impact of zooplankton.
  • OceanCertaim ( is a EU-funded project studying the effects of Global Change on ocean food webs and biogeochemical cycles both from a natural and a social sciences perspective. We lead the WP 1 (data mining) and contribute to WP 1.2 (modeling).
  • DynaTrait ( is a DFG-funded priority program studying the role of trait diversity for community and ecosystem dynamics and function. Our subproject (TraitHist) focusses on the role phytoplankton size for nutrient cycling, grazing and sedimentation.
  • BIOACID ( is a BMBF-funded project to study the effect of ocean acidification on marine ecosystems and organisms. We contribute the WPs 1.9 and 1.10. which analyze the combined effects of CO2 and temperature on phyto- and zooplankton by mesocosm experiments.


See publication lists in the homepages of the team members