Maintenance of Intraspecific Diversity in Response to Species Competition and Nutrient Fluctuations

• Published in: Microorganisms (Basel) Vol. 10; no. 1; p. 113
• Main Authors: Hamer, Jorin, Matthiessen, Birte, Pulina, Silvia, Hattich, Giannina S I
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 06.01.2022; MDPI
• Subjects: Biodiversity; Cell size; Climate change; Competition; Emiliania huxleyi; Environmental conditions; Enzyme kinetics; Experiments; Fluctuations; Genetic diversity; Genotype & phenotype; Genotypes; intraspecific diversity; Maintenance; nutrient fluctuations; Nutrients; Phytoplankton; Plankton; Species; Species diversity; trait variability; Velocity; Emiliania huxleyi; genotype coexistence; Vmax; trait variability; phytoplankton; Chaetoceros affinis; competition; intraspecific diversity; cell size; nutrient fluctuations
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms10010113

Intraspecific diversity is a substantial part of biodiversity, yet little is known about its maintenance. Understanding mechanisms of intraspecific diversity shifts provides realistic detail about how phytoplankton communities evolve to new environmental conditions, a process especially important in times of climate change. Here, we aimed to identify factors that maintain genotype diversity and link the observed diversity change to measured phytoplankton morpho-functional traits and cell size of the species and genotypes. In an experimental setup, the two phytoplankton species and , each consisting of nine genotypes, were cultivated separately and together under different fluctuation and nutrient regimes. Their genotype composition was assessed after 49 and 91 days, and Shannon's diversity index was calculated on the genotype level. We found that a higher intraspecific diversity can be maintained in the presence of a competitor, provided it has a substantial proportion to total biovolume. Both fluctuation and nutrient regime showed species-specific effects and especially structured genotype sorting of . While we could relate species sorting with the measured traits, genotype diversity shifts could only be partly explained. The observed context dependency of genotype maintenance suggests that the evolutionary potential could be better understood, if studied in more natural settings including fluctuations and competition.