Microbial carbon oxidation in seawater below the hypoxic threshold.

ABSTRACT: Global oxygen minimum zones (OMZs) often reach hypoxia but seldom reach anoxia. Recently it was reported that Michaelis Menten constants (K_m) of oxidative enzymes are orders of magnitude higher than respiratory K_m values, and in the Hypoxic Barrier Hypothesis it was proposed that, in ecosystems experiencing falling oxygen, oxygenase enzyme activities become oxygen-limited long before respiration. We conducted a mesocosm experiment with a phytoplankton bloom as an organic carbon source and controlled dissolved oxygen (DO) concentrations in the dark to determine whether hypoxia slows carbon oxidation and oxygen decline. Total oxygen utilization (TOU) in hypoxic treatment (ca. 7.1 µM O₂) was 21.7% lower than the oxic treatment (ca. 245.1 µM O₂) over

SUBMITTER: Wolf S 

PROVIDER: S-EPMC11754627 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature