Abstracts (first author)

Talk 

Potential and constrains of adaptation to ocean acidification in the globally important marine phytoplankton species Emiliania huxleyi

Author(s): Lohbeck KT, Riebesell U, Collins S, Reusch TBH

Summary:

The biological impacts of climate change and the associated acidification of the surface ocean are intensely studied, with likely consequences for biodiversity and ecosystem functioning emerging as a consensus. However, evolutionary responses have only recently been considered. Marine microbes with short generation times and large population size are good candidates for testing the evolutionary potential to respond to ocean acidification. We used the globally important marine phytoplankton species Emiliania huxleyi for a 1000 generation selection experiment in elevated CO2 and found that adaptive evolution to ocean acidification is possible and likely fast enough to act on time scales relevant to climate change. Replicate populations selected under high CO2 consistently revealed higher fitness than control populations under ocean acidification conditions. To investigate whether such phenotypic convergence involves the same or different mutations, we exposed adapted populations to a novel environment where pleiotropic effects can serve as a proxy for divergent genetic bases of previous adaptation to high CO2. We identified divergent functional genetic bases in replicate high CO2 adapted but not in control populations. This indicates that many evolutionary trajectories to high CO2 adaptation are possible in E. huxleyi but also suggests that pleiotropy may constrain adaptation of natural E. huxleyi populations to ocean acidification. Our results highlight the urgent need to consider evolutionary processes when assessing the responses of marine microbes to future ocean conditions.



Abstracts (coauthor)

Summary:

Ocean acidification, the drop in seawater pH due to the uptake of anthropogenic CO2, is a major threat to marine calcifying organisms. In a long-term evolution experiment, we found that the biogeochemically important unicellular algae Emiliania huxleyi partly restored calcification and growth rates at elevated CO2 owing to adaptive evolution, compared to control lines kept at ambient CO2 levels. In order to unravel the genetic basis of adaptive change we re-sequenced replicated control and adapted populations to a high coverage. We identified SNPs and other polymorphisms that diverged with respect to CO2 selection treatments via mapping to the existing genome of E. huxleyi. We were particularly interested whether or not the same genes or metabolic pathways were affected, and how consistent these changes were across replicates. These data provide first insights into the dynamics and the parallelism of de novo mutations in an ecologically important phytoplankton species.

Contacts

Chairman: Octávio S. Paulo
Tel: 00 351 217500614 direct
Tel: 00 351 217500000 ext22359
Fax: 00 351 217500028
email: mail@eseb2013.com

Address

XIV Congress of the European Society for Evolutionary Biology

Organization Team
Department of Animal Biology (DBA)
Faculty of Sciences of the University of Lisbon
P-1749-016 Lisbon
Portugal

Website

Computational Biology & Population Genomics Group 
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