Prokaryotic Responses to Ammonium and Organic Carbon Reveal Alternative CO₂ Fixation Pathways and Importance of Alkaline Phosphatase in the Mesopelagic North Atlantic.

ABSTRACT: To decipher the response of mesopelagic prokaryotic communities to input of nutrients, we tracked changes in prokaryotic abundance, extracellular enzymatic activities, heterotrophic production, dark dissolved inorganic carbon (DIC) fixation, community composition (16S rRNA sequencing) and community gene expression (metatranscriptomics) in 3 microcosm experiments with water from the mesopelagic North Atlantic. Responses in 3 different treatments amended with thiosulfate, ammonium or organic matter (i.e., pyruvate plus acetate) were compared to unamended controls. The strongest stimulation was found in the organic matter enrichments, where all measured rates increased >10-fold. Strikingly, in the organic matter treatment, the dark DIC fixation rates-assumed to be related to autotrophic metab

SUBMITTER: Baltar F 

PROVIDER: S-EPMC5073097 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature