Journal d'océanographie et de recherche marine
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Abstrait

Estimating the Genetic Capability of Different Phytoplankton Organisms to Adapt to Climate Warming

Costas E, Baselga-Cervera B, García-Balboa C and Lopez-Rodas V

Current predictions of temperature increase in sea surface water estimate that extensive regions of the ocean will be warmer than at any time in the past million years as a consequence of the present trend of release the CO2 excess into the atmosphere. Studying the capacity of phytoplankton to adapt to warming has become a relevant issue because phytoplankton represents the basis of the aquatic food web supporting about half of the global primary production. Considering the complexity of the phytoplankton community in both taxonomic level and habitat preferences, different responses to increased temperature are expected.We experimentally estimate the potential of different phytoplanktonic populations of 15 species, belonging to different taxonomic groups (Cyanoprokaryota, Dinophyta, Chlorophyta, Haptophyta, Heterokontophyta) and habitat preferences (e.g. coastal waters, open ocean, coral symbiotic), to genetically adapt in an evolutionary sense to marine warming.Since genetic variance in fitness estimates capability for adaptation of a population (Fisher’s Fundamental Theorem of Natural Selection) we measured the heritability of fitness (i.e. proportion of variance in fitness that has genetic basis) under increasing temperatures, using an experimental quantitative genetic procedure suitable to phytoplankton populations. Our results reveal that there are interspecific differences in phytoplankton capability for adaptation under a gradual warming process and provides experimental evidences for assessing how phytoplanktonic organisms might evolve under climate warming in the near future.