Multi-trait diversification in marine diatoms in constant and warmed environments

Area of Science:

• Marine biology
• Evolutionary biology
• Microbial ecology

Background:

• Phytoplankton are crucial marine microbes influencing ecosystems and climate.
• Their ecological roles are dictated by functional traits like cell size and chlorophyll content.
• Understanding trait evolution is key to predicting phytoplankton responses to environmental change.

Purpose of the Study:

• To investigate evolutionary patterns in interrelated phytoplankton functional traits.
• To explore how environmental novelty affects multi-trait evolution.
• To visualize trait evolution using a trait-scape approach.

Main Methods:

• Diversified six Thalassiosirid diatom genotypes using population bottlenecks.
• Evolved large populations in two distinct environments.
• Analyzed nine traits and their correlations using reduced axes (trait-scape).

Main Results:

• Evolving populations shifted within the trait-scape, with more frequent shifts in novel environments.
• Evolution of trait relationships was population-specific.
• Greater divergence from ancestral trait correlations correlated with reduced population growth rates.

Conclusions:

• Multi-trait evolution in diatoms is repeatable along a major axis, not driven by a single trait.
• Trait-scapes effectively visualize changes in trait values and relationships.
• This approach offers insights into complex multi-trait evolutionary dynamics.