title: Metaproteomics reveals differential modes of metabolic coupling among ubiquitous oxygen minimum zone microbes.
abstract: Marine oxygen minimum zones (OMZs) are intrinsic water column features arising from respiratory oxygen demand during organic matter degradation in stratified waters. Currently OMZs are expanding due to global climate change with resulting feedback on marine ecosystem function. Here we use metaproteomics to chart spatial and temporal patterns of gene expression along defined redox gradients in a seasonally stratified fjord to better understand microbial community responses to OMZ expansion. The expression of metabolic pathway components for nitrification, anaerobic ammonium oxidation (anammox), denitrification, and inorganic carbon fixation were differentially expressed across the redoxcline and covaried with distribution patterns of ubiquitous OMZ microbes including Thaumarchaeota, Nitrospina, Nitrospira, Planctomycetes, and SUP05/ARCTIC96BD-19 Gammaproteobacteria. Nitrification and inorganic carbon fixation pathways affiliated with Thaumarchaeota dominated dysoxic waters, and denitrification, sulfur oxidation, and inorganic carbon fixation pathways affiliated with the SUP05 group of nitrate-reducing sulfur oxidizers dominated suboxic and anoxic waters. Nitrifier nitrite oxidation and anammox pathways affiliated with Nirospina, Nitrospira, and Planctomycetes, respectively, also exhibited redox partitioning between dysoxic and suboxic waters. The numerical abundance of SUP05 proteins mediating inorganic carbon fixation under anoxic conditions suggests that SUP05 will become increasingly important in global ocean carbon and nutrient cycling as OMZs expand.
authors: Department of Microbiology and Immunology.
authors: Alyse K
authors: AK
authors: Hawley
authors: Biological and Computational Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352.
authors: Heather M
authors: HM
authors: Brewer
authors: Biological and Computational Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352.
authors: Angela D
authors: AD
authors: Norbeck
authors: Biological and Computational Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352.
authors: Ljiljana
authors: L
authors: Paša-Tolić
authors: Department of Microbiology and Immunology,Graduate Program in Bioinformatics, andGenome Sciences and Technology Training Program, University of British Columbia, Vancouver, BC, Canada V6T 1Z3; and shallam@mail.ubc.ca.
authors: Steven J
authors: SJ
authors: Hallam
mesh_terms: D001105:Archaea / Q000235:genetics / Q000378:metabolism*; D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D016000:Cluster Analysis; D017753:Ecosystem; D004734:Energy Metabolism; D020869:Gene Expression Profiling; D019848:Gene Expression Regulation, Archaeal; D015964:Gene Expression Regulation, Bacterial; D019766:Genes, Archaeal; D005798:Genes, Bacterial; D008954:Models, Biological; D009584:Nitrogen / Q000378:metabolism; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D020543:Proteome / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D013455:Sulfur / Q000378:metabolism; D014867:Water / Q000737:chemistry
chemical_list: D020543:Proteome; D014867:Water; D013455:Sulfur; D009584:Nitrogen; D010100:Oxygen