Understanding how phytoplankton response to elevated CO2 and/or warming through long-term genotypic adaptation is critical for predicting future phytoplankton distribution and community structure. In this study, we conducted a 4.5-year experimental evolution with the model marine diatom Phaeodactylum tricornutum Bohlin under four environmental regimes: ambient conditions, high CO2, warming, and combined high CO2 + warming. Following this long-term adaptation, we exposed the populations to a broad CO2 gradient in a short-term (7-day) experiment, assessing their multi-trait responses. Our results demonstrate that P. tricornutum Bohlin populations adapted to different regimes exhibit significant multi-trait variation across CO2 gradients. Notably, the variability driven by long-term adaptation exceeded that induced by short-term CO2 changes. Furthermore, both long-term adaptation and short-term CO2 exposure altered trait co-variations, highlighting the complex interplay between environmental history and immediate conditions. This study emphasizes the importance to assess long-term genetic changes in marine phytoplankton under global change, as short-term experiments alone may underestimate their capacity for adaptation and the broader implications for marine ecosystems under future climate scenarios.
Peng B., Ye M., Li J., Zhang H., Xu L., Jia Y., Wang Y. P., Huang B., Liu F., Liu P., Lin J., Wu F., Xia J. & Jin P., 2024. Adaptation to warming and high CO2 influences diatom response norms and multi-trait variations across CO2 gradients. Journal of Plant Ecology: rtae116. doi: 10.1093/jpe/rtae116. Article.
