Diel study reveals increased nighttime bacterial activity and its connection to organic compounds in the ocean.

ABSTRACT: The linkages between dissolved organic matter (DOM) dynamics and bacterial activity (BAct) are key to regulating carbon fluxes in marine food webs. While transcriptional activities have shown diel patterns, the connections between BAct and DOM on the diel timescale remain unclear. This study explored how bacterioplankton transform DOM over diel cycles in the euphotic and upper twilight zones (to 300 m) of the North Atlantic subtropical gyre. BAct peaked at night in the euphotic zone, following daytime maxima in chlorophyll fluorescence, suggesting a delayed bacterial response to photosynthetic activity. Our data show nighttime BAct exceeded daytime rates 34-47% under dark incubations. Total dissolved amino acids (TDAA) concentrations were lowest at night in the upper twilight waters, indic

SUBMITTER: Liu S 

PROVIDER: S-EPMC12658054 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature