Intraspecific variation in metal tolerance modulate competition between two marine diatoms

Björn Andersson, Anna Godhe, Helena L. Filipsson, Linda Zetterholm, Lars Edler, Olof Berglund, Karin Rengefors

Research output: Contribution to journalArticlepeer-review


Despite widespread metal pollution of coastal ecosystems, little is known of its effect on marine phytoplankton. We designed a co-cultivation experiment to test if toxic dose–response relationships can be used to predict the competitive outcome of two species under metal stress. Specifically, we took into account intraspecific strain variation and selection. We used 72 h dose–response relationships to model how silver (Ag), cadmium (Cd), and copper (Cu) affect both intraspecific strain selection and competition between taxa in two marine diatoms (Skeletonema marinoi and Thalassiosira baltica). The models were validated against 10-day co-culture experiments, using four strains per species. In the control treatment, we could predict the outcome using strain-specific growth rates, suggesting low levels of competitive interactions between the species. Our models correctly predicted which species would gain a competitive advantage under toxic stress. However, the absolute inhibition levels were confounded by the development of chronic toxic stress, resulting in a higher long-term inhibition by Cd and Cu. We failed to detect species differences in average Cu tolerance, but the model accounting for strain selection accurately predicted a competitive advantage for T. baltica. Our findings demonstrate the importance of incorporating multiple strains when determining traits and when performing microbial competition experiments.

Original languageEnglish
Article number
Pages (from-to)511-520
JournalISME Journal
Publication statusPublished - 2022

Bibliographical note

Funding Information:
This project was funded by the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS) grant number 2016-00594, and the Oscar and Lili Lamm Foundation grant number FO2018-0042.

Subject classification (UKÄ)

  • Ecology

Free keywords

  • plankton
  • metal pollution


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