Evolution of natural algal populations at elevated CO2

Area of Science:

• Environmental microbiology
• Evolutionary biology
• Climate change science

Background:

• Atmospheric carbon dioxide (CO2) levels are projected to double this century.
• Microbial populations, with rapid generation times, are candidates for rapid evolutionary adaptation to environmental changes.
• Investigating microalgal responses to elevated CO2 provides insights into ecosystem adaptation.

Discussion:

• Microalgae from natural high-CO2 springs and laboratory-selected Chlamydomonas strains did not evolve specific adaptations to elevated CO2.
• Both natural and laboratory populations contained strains that grew poorly at ambient CO2 levels.
• Some microalgal lines demonstrated growth rates insensitive to CO2 concentrations, suggesting pre-existing variation.

Key Insights:

• Long-term CO2 enrichment does not necessarily drive specific evolutionary adaptations in microalgae.
• Natural populations in high-CO2 environments may harbor pre-existing genetic variation for CO2 tolerance.
• Laboratory selection experiments can mimic evolutionary outcomes observed in natural CO2-enriched ecosystems.

Outlook:

• Further research is needed to understand the genetic basis of CO2 insensitivity in microalgae.
• Assessing the broader ecological implications of microalgal adaptation to changing CO2 levels is crucial.
• This study highlights the importance of considering natural variation when predicting evolutionary responses to climate change.