Microbial plankton responses to multiple environmental drivers in marine ecosystems with different phosphorus limitation degrees Jabalera Cabrerizo, Marco Medina Sánchez, Juan Manuel Sánchez Gómez, Daniel Carrillo Lechuga, Presentación González Olalla, Juan Manuel Carbon dioxide Metabolic balance Nutrients supply Phytoplankton-bacteria relationship Ultraviolet radiation Warming We thank R/V UCÁDIZ crew, and Eulogio Corral by their help during seawater sampling. Cristina Estevan-Pardo is acknowledged by her collaboration during the experiments, and David Nesbitt for the English proofreading. Comments and suggestions by the Associated Editor Dr. Blasco and three anonymous reviewers are deeply acknowledged. This research was funded by ‘convocatoria de proyectos de jóvenes investigadores CEIMAR 2018’ from Campus de Excelencia Internacional del Mar (MIXOCOST, CEIJ-008 to MJC), and by Ministerio de Economía y Competitividad and Fondo Europeo de Desarrollo regional (FEDER) (METAS, CGL2015-67682-R to PC and JMM-S). MJC was supported by Juan de la Cierva-Formación ( FJCI2017-32318 ) and Incorporación ( IJC2019-040850-I ) grants from Ministerio de Ciencia, Innovación y Universidades . JMG-O was supported by University of Granada through programa de promoción y empleo joven from Junta de Andalucía and FEDER ( PEJ2018-003106-A ), and DS-G by METAS project. Multiple drivers are threatening the functioning of the microbial food webs and trophic interactions. Our understanding about how temperature, CO2, nutrient inputs, and solar ultraviolet radiation (UVR) availability interact to alter ecosystem functioning is scarce because research has focused on single and double interactions. Moreover, the role that the degree of in situ nutrient limitation could play in the outcome of these interactions has been largely neglected, despite it is predominant in marine ecosystems. We address these uncertainties by combining remote-sensing analyses, and a collapsed experimental design with natural microbial communities from Mediterranean Sea and Atlantic Ocean exposed to temperature, nutrients, CO2, and UVR interactions. At the decade scale, we found that more intense and frequent (and longer lasting) Saharan dust inputs (and marine heatwaves) were only coupled with reduced phytoplankton biomass production. When microbial communities were concurrently exposed to future temperature, CO2, nutrient, and UVR conditions (i.e. the drivers studied over long-term scales), we found shifts from net autotrophy [primary production:respiration (PP:R) ratio > 1] towards a metabolic equilibrium (PP:R ratio ~ 1) or even a net heterotrophy (PP:R ratio < 1), as P-limitation degree was higher (i.e. Atlantic Ocean). These changes in the metabolic balance were coupled with a weakened phytoplankton-bacteria interaction (i.e. bacterial carbon demand exceeded phytoplankton carbon supply. Our work reveals that an accentuated in situ P limitation may promote reductions both in carbon uptake and fluxes between trophic levels in microbial plankton communities under global-change conditions. We show that considering long-term series can aid in identifying major local environmental drivers (i.e. temperature and nutrients in our case), easing the design of future global-change studies, but also that the abiotic environment to which microbial plankton communities are acclimated should be taken into account to avoid biased predictions concerning the effects of multiple interacting global-change drivers on marine ecosystems. 2021-11-29T11:05:16Z 2021-11-29T11:05:16Z 2021-11-06 journal article M.J. Cabrerizo, J.M. Medina-Sánchez, J.M. González-Olalla, et al., Microbial plankton responses to multiple environmental drivers in marine ecosystems with different p..., Science of the Total Environment, [https://doi.org/10.1016/j.scitotenv.2021.151491] http://hdl.handle.net/10481/71812 10.1016/j.scitotenv.2021.151491 eng http://creativecommons.org/licenses/by/3.0/es/ open access Atribución 3.0 España Elsevier