Saanich Inlet Oxygen Minimum Zone Redox-Gradient Community

Community ID CommunityMech:000140

Ecological State PERTURBED

Environment seasonally anoxic marine fjord water column
ENVO:00002149

A natural marine water-column microbial community from Saanich Inlet, a seasonally anoxic fjord on Vancouver Island, Canada that serves as a model oxygen minimum zone. Integrated geochemistry, rate measurements, metagenomics, metatranscriptomics, metaproteomics, and qPCR link community structure to coupled carbon, nitrogen, and sulfur cycling across a redox gradient, including SUP05-driven incomplete sulfide-dependent denitrification, nitrite leakage supporting anammox, and a complementary nitrous oxide reduction niche.

Taxonomy

Taxon	Ontology ID	Functional Roles	Abundance
SUP05 Gammaproteobacteria	NCBITaxon:1236	PRIMARY_PRODUCER CROSS_FEEDER	DOMINANT
PMID:27655888 - SUPPORT (COMPUTATIONAL) "incomplete sulfide-driven denitrification by SUP05 Gammaproteobacteria is predicted to support inorganic carbon fixation and intense nitrogen loss via anaerobic ammonium oxidation." PMID:27655888 - SUPPORT (IN_VIVO) "qPCR-based abundance estimates for SUP05 Gammaproteobacteria-the dominant denitrifiers in Saanich Inlet"
anammox bacteria	NCBITaxon:2	PRIMARY_PRODUCER	N/A
PMID:27655888 - SUPPORT (COMPUTATIONAL) "genes associated with partial denitrification to nitrous oxide, nitrous oxide reduction, and anammox are most abundant in the SNTZ"
unidentified nitrous oxide reducers	NCBITaxon:2	CROSS_FEEDER	N/A
PMID:27655888 - SUPPORT (COMPUTATIONAL) "This coupling creates a metabolic niche for nitrous oxide reduction that completes denitrification by currently unidentified community members."

Ecological Interactions

Taxon

Cross-feeding

Mutualism

Syntrophy

Competition

Commensalism

Niche partitioning

Colonization facilitation

Strain competition

Predation

SUP05 Nitrite Leakage Supports Anammox

CROSS_FEEDING

Source Taxon: SUP05 Gammaproteobacteria

Target Taxon: anammox bacteria

Metabolites: nitrate (CHEBI:17632), nitrite (CHEBI:16301), hydrogen sulfide (CHEBI:16136), ammonium (CHEBI:28938)

Biological Processes:

denitrification (GO:0019333)
oxidation-reduction process (GO:0055114)

Evidence

PMID:27655888 - SUPPORT (COMPUTATIONAL)

"nitrite leakage during incomplete sulfide-driven denitrification by SUP05 Gammaproteobacteria is predicted to support inorganic carbon fixation and intense nitrogen loss via anaerobic ammonium oxidation."
PMID:27655888 - SUPPORT (COMPUTATIONAL)

"incomplete sulfide-driven denitrification can be an important precursor for anammox"

Complementary Nitrous Oxide Reduction Niche

NICHE_PARTITIONING

Source Taxon: SUP05 Gammaproteobacteria

Target Taxon: unidentified nitrous oxide reducers

Metabolites: nitrous oxide (CHEBI:17045), hydrogen sulfide (CHEBI:16136)

Biological Processes:

denitrification (GO:0019333)
oxidation-reduction process (GO:0055114)

Evidence

PMID:27655888 - SUPPORT (COMPUTATIONAL)

"The absence of nosZ from SUP05 suggests that incomplete nitrate reduction by SUP05 and reduction of nitrous oxide by unidentified community members constitute separate and complementary metabolic niches"

Redox-Driven Pathway Partitioning

NICHE_PARTITIONING

Source Taxon: Saanich Inlet redox-gradient microorganisms

Metabolites: dioxygen (CHEBI:15379), nitrate (CHEBI:17632), hydrogen sulfide (CHEBI:16136)

Biological Processes:

nitrification (GO:0019329)
denitrification (GO:0019333)
oxidation-reduction process (GO:0055114)

Evidence

PMID:27655888 - SUPPORT (COMPUTATIONAL)

"the model predicts a redox-driven partitioning of pathways across the water column."

Associated Datasets

Dataset	Type	Repository	Accession
Saanich Inlet 2010 multiomic redox-gradient profiles Supplementary metagenomic, metatranscriptomic, metaproteomic, qPCR, geochemical, and rate data used in the Saanich Inlet gene-centric biogeochemical model.	OTHER	OTHER	PNAS-1602897113-Datasets-S1-S2

Environmental Factors

Factor	Value	Unit
Seasonally anoxic fjord oxygen minimum zone	Saanich Inlet, Vancouver Island, Canada	N/A
PMID:27655888 - SUPPORT (IN_VIVO) "Saanich Inlet, a seasonally anoxic fjord with biogeochemistry analogous to oxygen minimum zones"
Sulfide-nitrate transition zone	model domain between 100 and 200 m at station SI03	N/A
PMID:27655888 - SUPPORT (IN_VIVO) "The model considers depths between 100 and 200 m." PMID:27655888 - SUPPORT (COMPUTATIONAL) "At the SNTZ in Saanich Inlet, the simultaneous availability of nitrate and hydrogen sulfide fuels chemoautotrophic nitrate reduction coupled to sulfide oxidation"