Local Adaptation and Osmoregulatory Mechanisms of the Copepod Acartia tonsa Under Low Salinity Stress.

ABSTRACT: Salinity-an essential factor shaping marine species distributions-is rapidly shifting due to global change, yet the mechanisms of salinity tolerance and adaptation remain poorly understood. We investigated local adaptation in the calanoid copepod Acartia tonsa, a broadly distributed marine species that thrives in the brackish Baltic Sea. Using a common-garden design, we compared physiological and transcriptomic responses to low salinity between populations from the North Sea (> 25 PSU) and the Baltic Sea (< 15 PSU). Baltic copepods exhibited significantly higher survival under low salinity, indicating local adaptation. While both populations shared a core osmoregulatory strategy involving active ion transport and regulation of amino acids, transcriptomic profiles revealed population-specif

SUBMITTER: Hahn A 

PROVIDER: S-EPMC12745923 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature