identifier: METPO:1000626 label: stenohaline definition: A halophily preference in which an organism can only tolerate a narrow range of salinity concentrations and cannot survive significant changes in environmental salt levels. definition_source: DOI:10.1186/s40168-024-01817-w trait_category: ENVIRONMENT term_kind: CLASS mapping_status: REVIEWED parent_traits: - METPO:1000629 created_by: Luke Wang evidence: - reference: DOI:10.1186/s40168-024-01817-w snippet: narrow range of salinity notes: Supports stenohaline microorganisms as organisms thriving within a narrow salinity range. causal_graphs: - graph_id: stenohaline_narrow_salinity_tolerance title: Stenohaline narrow-salinity tolerance mechanism description: Evidence-backed causal sketch linking stenohalinity to narrow salinity niches, osmotic imbalance during salinity shifts, and constrained salinity-adaptation capacity. nodes: - node_id: stenohaline_trait label: stenohaline node_type: TRAIT grounding: METPO:1000626 description: Tolerance is limited to a narrow range of salinity concentrations. - node_id: narrow_salinity_range label: narrow salinity range node_type: ENVIRONMENTAL_FACTOR description: Restricted salinity interval that supports growth. - node_id: salinity_shift label: salinity shift node_type: ENVIRONMENTAL_FACTOR description: Environmental increase or decrease in salt concentration. - node_id: osmotic_imbalance label: osmotic imbalance node_type: BIOLOGICAL_PROCESS description: Difference between external and internal osmotic potential. - node_id: water_flux label: water flux across cytoplasmic membrane node_type: BIOLOGICAL_PROCESS description: Osmotically driven water movement across the cell membrane. - node_id: salinity_adaptation_genes label: salinity-adaptation genes node_type: GENE_OR_PROTEIN description: Gene repertoires associated with adaptation along salinity gradients. - node_id: c_di_amp label: cyclic di-AMP node_type: CHEMICAL description: Second messenger nucleotide that regulates osmolyte and K+ transport in bacteria. grounding: CHEBI:71578 - node_id: k_import_systems label: K+ import systems node_type: GENE_OR_PROTEIN description: Potassium uptake transporters (Trk/Ktr/Kup/Kdp-type) mediating salt-in osmoadaptation. - node_id: opua_importer label: compatible-solute importer OpuA node_type: GENE_OR_PROTEIN description: ABC-type transporter importing compatible solutes such as glycine betaine. - node_id: low_c_di_amp_state label: low c-di-AMP state node_type: STATE description: Cellular condition of reduced c-di-AMP, derepressing osmolyte and K+ uptake. - node_id: k_solute_uptake label: K+ and compatible-solute uptake node_type: BIOLOGICAL_PROCESS description: Combined import of potassium and compatible solutes for osmotic adjustment. - node_id: osmotic_upshift label: osmotic upshift node_type: ENVIRONMENTAL_FACTOR description: Increase in external osmolarity, e.g. a rise in environmental salinity. - node_id: rapid_k_import label: rapid K+ import node_type: BIOLOGICAL_PROCESS description: Fast potassium influx mounted as an early osmoadaptation response. - node_id: compatible_solute_accumulation label: compatible-solute accumulation node_type: BIOLOGICAL_PROCESS description: Intracellular buildup of compatible solutes (proline, ectoine, trehalose). - node_id: salt_out_osmoadaptation label: salt-out osmoadaptation node_type: BIOLOGICAL_PROCESS description: Long-term osmoadaptation via synthesis/import of compatible solutes. - node_id: aquaporin_water_channel label: aquaporin water-channel activity node_type: MOLECULAR_FUNCTION description: Channel activity (COG0580 / GO:0015250) enabling facilitated water diffusion. - node_id: facilitated_water_diffusion label: facilitated water diffusion node_type: BIOLOGICAL_PROCESS description: Passive water movement across the membrane through aquaporin channels. edges: - subject: narrow_salinity_range predicate: defines object: stenohaline_trait description: Stenohaline microorganisms thrive within a narrow salinity range. evidence: - reference: DOI:10.1186/s40168-024-01817-w snippet: narrow range of salinity notes: Microbiome study explicitly defines stenohaline microorganisms by a narrow salinity range. predicate_id: METPO:2007500 - subject: salinity_shift predicate: causes object: osmotic_imbalance description: Salinity shifts create osmotic imbalance across the membrane. evidence: - reference: DOI:10.1186/s40168-024-01817-w snippet: In response to osmotic imbalance notes: Supports osmotic imbalance as a response to salinity change. predicate_id: biolink:causes - subject: osmotic_imbalance predicate: regulates object: water_flux description: Osmotic imbalance drives water flux across the membrane. evidence: - reference: DOI:10.1186/s40168-024-01817-w snippet: water immediately rushes into the cell notes: Supports water flux during osmotic imbalance. predicate_id: RO:0002211 - subject: salinity_adaptation_genes predicate: regulates object: stenohaline_trait description: Salinity adaptation gene repertoires help determine salinity niche breadth; limited repertoires can correspond to narrow tolerance. evidence: - reference: DOI:10.1186/s40168-024-01817-w snippet: genes associated with microbial salinity adaptation notes: The constraint direction is inferred from the study's salinity adaptation analysis; kept broad because organism-specific gene sets vary. predicate_id: RO:0002211 - subject: salinity_shift predicate: exceeds tolerance of object: stenohaline_trait description: Large salinity changes can exceed the narrow tolerance range of stenohaline organisms. evidence: - reference: DOI:10.1186/s40168-024-01817-w snippet: Organisms thriving within a narrow range of salinity notes: Supports the ecological interpretation that large salinity excursions exceed stenohaline niche breadth. - subject: c_di_amp predicate: inhibits object: k_import_systems description: c-di-AMP binds RCK-type gating subunits to inhibit potassium influx. evidence: - reference: DOI:10.1128/mmbr.00181-23 notes: c-di-AMP binds RCK-type gating subunits inhibiting potassium influx; broad regulatory principle across c-di-AMP bacteria. predicate_id: RO:0002212 - subject: c_di_amp predicate: inhibits object: opua_importer description: c-di-AMP binds CBS-containing compatible-solute importers and negatively regulates their transport. evidence: - reference: DOI:10.1128/mmbr.00181-23 notes: Binds CBS-containing compatible-solute importers (OpuA, OpuC, OpuD) and negatively regulates transport; general osmoadaptation regulation. predicate_id: RO:0002212 - subject: low_c_di_amp_state predicate: increases object: k_solute_uptake description: Low c-di-AMP increases uptake of K+ and compatible solutes. evidence: - reference: DOI:10.1128/mmbr.00181-23 notes: Low c-di-AMP mutants show increased uptake of K+ and compatible solutes; broad bacterial principle. predicate_id: RO:0002213 - subject: osmotic_upshift predicate: triggers object: rapid_k_import description: Osmotic upshift triggers rapid K+ import as an early osmoadaptation response. evidence: - reference: DOI:10.1093/femsml/uqad020 notes: Many bacteria mount a rapid K+ import upon osmotic upshift; canonical osmoadaptation edge, not specific to stenohaline microbes. - subject: compatible_solute_accumulation predicate: supports object: salt_out_osmoadaptation description: Accumulation of compatible solutes supports the salt-out osmoadaptation strategy. evidence: - reference: DOI:10.1093/femsml/uqad020 notes: Longer-term strategy is salt-out via synthesis/import of compatible solutes (proline, ectoine, trehalose); general mechanistic edge. - subject: aquaporin_water_channel predicate: enables object: facilitated_water_diffusion description: Aquaporin water-channel activity enables facilitated diffusion of water. evidence: - reference: DOI:10.1186/s40168-024-01817-w notes: COG0580 linked to GO:0015250 and described as enabling facilitated diffusion of water; functional edge. predicate_id: RO:0002327 curation_history: - timestamp: '2026-05-05T01:35:46.864123+00:00' curator: seed_from_metpo action: SEEDED_FROM_METPO changes: imported from data/raw/metpo.owl (CLASS) llm_assisted: false - timestamp: '2026-05-11T00:00:00-07:00' curator: codex action: CURATED_WITH_LITERATURE changes: Reviewed stenohaline trait and added DOI-backed causal graph for narrow salinity tolerance, salinity-shift osmotic imbalance, water flux, and constrained salinity-adaptation capacity. llm_assisted: true - timestamp: '2026-05-20T05:49:24Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (biolink:causes×1). llm_assisted: true - timestamp: '2026-05-24T04:13:18Z' curator: claude action: RENAME_PREDICATE_LABELS changes: 'Renamed 1 causal-edge predicate label(s) to align with existing groundings: drives → regulates ×1.' llm_assisted: true - timestamp: '2026-05-24T04:13:21Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (RO:0002211×1). llm_assisted: true - timestamp: '2026-05-24T07:37:39Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (METPO:2007500×1). llm_assisted: true - timestamp: '2026-05-26T05:00:47Z' curator: claude action: RENAME_PREDICATE_LABELS changes: 'Renamed 1 causal-edge predicate label(s) to align with existing groundings: constrains → regulates ×1.' llm_assisted: true - timestamp: '2026-05-26T05:00:50Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (RO:0002211×1). llm_assisted: true - timestamp: '2026-06-17T04:09:43Z' curator: claude action: REMOVE_REDUNDANT_SYNONYM changes: Removed 1 synonym(s) whose text duplicated the label (seeder redundancy; no information lost). llm_assisted: true - timestamp: '2026-06-23T00:00:00Z' curator: claude action: ENRICH_CAUSAL_GRAPH changes: Added 6 evidence-backed generic edges (11 new nodes) from the deep-research report. llm_assisted: true - timestamp: '2026-06-24T17:21:11Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 4 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (RO:0002212×2, RO:0002213×1, RO:0002327×1). llm_assisted: true - timestamp: '2026-06-24T17:23:31Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv (CHEBI:71578×1). llm_assisted: true