Microbial carbon oxidation in seawater below the hypoxic threshold.

Fuente: PubMed
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Autores principales: Wolf, Sarah, Jayawickrama, Clare, Carlson, Craig A, Deutsch, Curtis, Davis, Edward W, Daniels, Benjamin N, Chan, Francis, Giovannoni, Stephen J
Formato: Artículo científico
Lenguaje:en
Publicado: Scientific reports 2025
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author Wolf, Sarah
Jayawickrama, Clare
Carlson, Craig A
Deutsch, Curtis
Davis, Edward W
Daniels, Benjamin N
Chan, Francis
Giovannoni, Stephen J
author_facet Wolf, Sarah
Jayawickrama, Clare
Carlson, Craig A
Deutsch, Curtis
Davis, Edward W
Daniels, Benjamin N
Chan, Francis
Giovannoni, Stephen J
Wolf, Sarah
Jayawickrama, Clare
Carlson, Craig A
Deutsch, Curtis
Davis, Edward W
Daniels, Benjamin N
Chan, Francis
Giovannoni, Stephen J
collection PubMed - marine biology
contents Microbial carbon oxidation in seawater below the hypoxic threshold. Wolf, Sarah Jayawickrama, Clare Carlson, Craig A Deutsch, Curtis Davis, Edward W Daniels, Benjamin N Chan, Francis Giovannoni, Stephen J Oxidation-Reduction Carbon Seawater Oxygen Microbiota Bacteria Phytoplankton Global oxygen minimum zones (OMZs) often reach hypoxia but seldom reach anoxia. Recently it was reported that Michaelis Menten constants (K) of oxidative enzymes are orders of magnitude higher than respiratory K 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 O) was 21.7% lower than the oxic treatment (ca. 245.1 µM O) over the first 43 days of the experiment. In addition, following the restoration of fully oxic conditions to the hypoxic treatment, TOU accelerated, demonstrating that oxidative processes are sensitive to DO concentrations found in large volumes of the ocean. Microbial amplicon-based community composition diverged between oxic treatments, indicating a specialized microbiome that included Thioglobaceae (SUP05 Gammaproteobacteria), OM190 (Planctomycetota), ABY1 (Patescibacteria), and SAR86 subclade D2472, thrived in the hypoxic treatment, while the genus Candidatus Actinomarina and SAR11 alphaproteobacteria were sharply inhibited. Our findings support the hypothesis that oxygenase kinetics might slow the progression of ocean deoxygenation in oxygen-poor regions and be a factor in the evolution of microbial taxa adapted to hypoxic environments.
format Artículo científico
id pubmed_39843462
institution PubMed
language en
publishDate 2025
publisher Scientific reports
record_format pubmed
spellingShingle Microbial carbon oxidation in seawater below the hypoxic threshold.
Wolf, Sarah
Jayawickrama, Clare
Carlson, Craig A
Deutsch, Curtis
Davis, Edward W
Daniels, Benjamin N
Chan, Francis
Giovannoni, Stephen J
Oxidation-Reduction
Carbon
Seawater
Oxygen
Microbiota
Bacteria
Phytoplankton
Microbial carbon oxidation in seawater below the hypoxic threshold. Wolf, Sarah Jayawickrama, Clare Carlson, Craig A Deutsch, Curtis Davis, Edward W Daniels, Benjamin N Chan, Francis Giovannoni, Stephen J Oxidation-Reduction Carbon Seawater Oxygen Microbiota Bacteria Phytoplankton Global oxygen minimum zones (OMZs) often reach hypoxia but seldom reach anoxia. Recently it was reported that Michaelis Menten constants (K) of oxidative enzymes are orders of magnitude higher than respiratory K 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 O) was 21.7% lower than the oxic treatment (ca. 245.1 µM O) over the first 43 days of the experiment. In addition, following the restoration of fully oxic conditions to the hypoxic treatment, TOU accelerated, demonstrating that oxidative processes are sensitive to DO concentrations found in large volumes of the ocean. Microbial amplicon-based community composition diverged between oxic treatments, indicating a specialized microbiome that included Thioglobaceae (SUP05 Gammaproteobacteria), OM190 (Planctomycetota), ABY1 (Patescibacteria), and SAR86 subclade D2472, thrived in the hypoxic treatment, while the genus Candidatus Actinomarina and SAR11 alphaproteobacteria were sharply inhibited. Our findings support the hypothesis that oxygenase kinetics might slow the progression of ocean deoxygenation in oxygen-poor regions and be a factor in the evolution of microbial taxa adapted to hypoxic environments.
title Microbial carbon oxidation in seawater below the hypoxic threshold.
topic Oxidation-Reduction
Carbon
Seawater
Oxygen
Microbiota
Bacteria
Phytoplankton
url https://pubmed.ncbi.nlm.nih.gov/39843462/