Heterotrophic bacterial production and metabolic balance during the VAHINE mesocosm experiment in the New Caledonia lagoon

Heterotrophic bacterial production (BP) was found to be significantly stimulated by nitrogen enrichment, suggesting nitrogen limitation of heterotrophic bacteria throughout the experiment. The study, conducted during the VAHINE mesocosm experiment in New Caledonia's lagoon, revealed that BP was highly correlated with particulate primary production and chlorophyll biomass but only slightly correlated with N2 fixation rates during the second phase (P2). Bacterial growth efficiency, at 27–43%, was notably higher than expected for oligotrophic environments, possibly due to the presence of proteorhodopsin-expressing bacteria. The main fates of gross primary production were respiration (67%) and sedimentation (17%). Diazotroph-derived nitrogen primarily fueled the heterotrophic bacterial community through indirect processes like mortality, lysis, and grazing.

Van Wambeke, F., Pfreundt, U., Barani, A., Berthelot, H., Moutin, T., Rodier, M., Hess, W. R., & Bonnet, S. (2016). Heterotrophic bacterial production and metabolic balance during the VAHINE mesocosm experiment in the New Caledonia lagoon. Biogeosciences, 13(11), 3187–3202. https://doi.org/10.5194/bg-13-3187-2016