biostudies-literatureBustos-Caparros ESpanish Government Ministry for Science and InnovationSpanish Ministry of Science, Innovation and UniversitiesFederation of European Microbiological SocietiesDiSC of University of InnsbruckEuropean Regional Development Fundswrae215https://www.ebi.ac.uk/biostudies/studies/S-EPMC11544370biostudies-literatureUnknown18(1)To understand how extreme halophiles respond to recurrent disturbances, we challenged the communities thriving in salt-saturated (~36% salts) ~230 L brine mesocosms to repeated dilutions down to 13% (D13 mesocosm) or 20% (D20 mesocosm) salts each time mesocosms reached salt saturation due to evaporation (for 10 and 17 cycles, respectively) over 813 days. Depending on the magnitude of dilution, the most prevalent species, Haloquadratum walsbyi and Salinibacter ruber, either increased in dominance by replacing less competitive populations (for D20, moderate stress conditions), or severely decreased in abundance and were eventually replaced by other congeneric species better adapted to the higher osmotic stress (for D13, strong stress conditions). Congeneric species replacement was commonly oThe ISME journalEcological success of extreme halophiles subjected to recurrent osmotic disturbances is primarily driven by congeneric species replacement.PMC11544370PID2021-126114NB-C42PGC2018-096956-B-C41PRE2019-088016FEMS-GO-2020-254Gago JFFuchs BMBosch RHatt JKViver TRodriguez-R LMAmann RKonstantinidis KTRossello-Mora RBustos-Caparros EVenter SNfalseEcological success of extreme halophiles subjected to recurrent osmotic disturbances is primarily driven by congeneric species replacement.To understand how extreme halophiles respond to recurrent disturbances, we challenged the communities thriving in salt-saturated (~36% salts) ~230 L brine mesocosms to repeated dilutions down to 13% (D13 mesocosm) or 20% (D20 mesocosm) salts each time mesocosms reached salt saturation due to evaporation (for 10 and 17 cycles, respectively) over 813 days. Depending on the magnitude of dilution, the most prevalent species, Haloquadratum walsbyi and Salinibacter ruber, either increased in dominance by replacing less competitive populations (for D20, moderate stress conditions), or severely decreased in abundance and were eventually replaced by other congeneric species better adapted to the higher osmotic stress (for D13, strong stress conditions). Congeneric species replacement was commonly o2024-01-01T00:00:00Z2024 Jan2026-07-16T15:05:28.051Z2026-07-10T03:09:38.129ZS-EPMC115443703944198910.1093/ismejo/wrae215