ALKALDIANational ProjectsProject duration: Jun 2020 to May 2023IntroductionIn this project, we investigate how pH and alkalinity gradients in inland waters can be axes of speciation and segregation, using diatoms as model organisms.The colonization of continental aquatic environments by life faced greater chemical variation than in the marine environment. The new ecophysiological challenges were an opportunity for functional and taxonomic diversification, and today this chemical variation remains as a relevant ecological and evolutionary framework. A large part of the chemical variation in inland waters is related to the nature of the rocky substrate and its weathering, resulting in more acidic or more buffered waters. There are several reasons why pH-alkalinity gradients (PAG) can be axes of speciation and segregation: carbon metabolism, particularly for primary producers; pH homeostasis; cellular signalling and regulatory activity related to cations; and rigid body/cell structures. Many groups of freshwater organisms have diversified throughout the PAGs. Diatoms are used in this project as model organisms.ObjectivesThe project aims to:1) determine if there are functional traits in diatoms whose spatial variation reflects the variation of PAGs;2) check if there are biogeographic patterns that relate the diversification of diatom clades with the distribution of PAGs across continents;3) evaluate how regional and long-term variation in PAGs affects metacommunity dynamics within a lake district;4) assess the effects of the rapid increase in atmospheric CO2 levels on the composition and functional traits of diatom communities. Proyecto PID2019-111137GB-C21 financiado por MCIN/ AEI /10.13039/501100011033 Other projects in the same field Behavior, ecology and evolution Cognitive buffer and population persistence under environmental change Evolutionary ecology Regional patterns of genomic and phenotypic trait variability associated with ADAPTation in Taxus baccata L.