Exploring the adaptive within- and between bloom dynamics of heterogenic dinoflagellate population of the toxigenic Alexandrium ostenfeldii in field and laboratory experiments.

• Applicant: Dr. Uwe John
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions ; Ecology and Biodiversity of Plants and Ecosystems ; Organismic Interactions, Chemical Ecology and Microbiomes of Plant Systems
• Term: from 2014 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 257505798

Traits that influence the interaction between species are of prime importance for population stability and species coexistence, because variation within these traits will directly determine species fitness and indirectly influence fitness of the interacting partner. In cases of antagonistic interactions including predation and competition variation of these traits will be selectively maintained. Therefore, any attempt in trying to understand diversity-resilience relationships should incorporate the functional variation of species interaction traits of ecosystem keystone species as a mechanistic basis. Here, we propose to investigate the selective maintenance of diversity in allelochemical production, a widespread trait to reduce competition and grazing during blooms of the dinoflagellate Alexandrium ostenfeldii, in relation to abiotic (nutrient limitation and temperature) and biotic (competition and predation) stressors. We will combine field observations, microcosm and chemostat experiments with cyst bed characterization and experimental evolution to link within bloom to between bloom dynamics. We hypothesize that fluctuating selection on allelochemical production and mutualistic interactions between producer and non-producer strains determines population dynamics and maintains diversity during the bloom. Between blooms the large number of compatible and incompatible mating types will be an efficient mechanism to maintain diversity as well as stability of mutualistic interactions. The link between trait diversity and population dynamics during decisive stages of the life cycle will therefore deepen our understanding of the relationship between biodiversity and ecosystem stability.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1704: Flexibility Matters: Interplay Between Trait Diversity and Ecological Dynamics Using Aquatic Communities as Model Systems (DynaTrait)
• International Connection: Netherlands, Sweden
• Participating Persons: Professorin Dr. Rosa Figueroa; Dr. Dedmer van de Waal; Dr. Mathias Wegner