HabitatMech

brackish water

ENVO:00002019 ·resolve ·AQUATIC ·EXACT SEEDED

Water which has a higher salinity than fresh water but a lower salinity than marine water. — ENVO

SEEDED workflow status. The source-seeding rules supplied this record; consult its curation history for later attributed changes. This status does not establish human review.

Source attestations

Each upstream vocabulary's own account of this habitat. Assertion counts are per-source units and are not comparable across sources — GOLD counts organisms, BacDive strains, PREGO taxa.

What each upstream vocabulary says about this habitat
SourceLabel / pathAssertionsUnit
ENVIRONMENTS_TABLE water_brackish
Physicochemical parameter bands from kg-microbe's environment table.		 —
MADIN brackish water 64 TAXON
PREGO brackish water 1015 TAXON

Broader habitats

Environmental parameters

Physicochemical parameters
ParameterValueSource
GRADIENTSlowkg-microbe environments.csv (water_brackish)
NUTRIENTSmediumkg-microbe environments.csv (water_brackish)
PHmediumkg-microbe environments.csv (water_brackish)
PRESSURElowkg-microbe environments.csv (water_brackish)
SALINITYmediumkg-microbe environments.csv (water_brackish)
SALINITY_VARIABILITYwidekg-microbe environments.csv (water_brackish)
STRUCTURAL_COMPLEXITYlowkg-microbe environments.csv (water_brackish)
TEMPERATURE_VARIABILITYmediumkg-microbe environments.csv (water_brackish)
WATER_AVAILABILITYhighkg-microbe environments.csv (water_brackish)
WATER_VARIABILITYpermanently wetkg-microbe environments.csv (water_brackish)

Causal graphs

Brackish water salinity-transition osmoregulation

Brackish water forms where freshwater inflow and seawater intrusion create intermediate salinity and tidal salinity variability. These osmotic shifts filter freshwater and marine bacterioplankton, select osmoregulatory transport and compatible-solute strategies, and allow brackish-adapted estuarine populations to establish when growth outpaces hydrologic flushing.

Directed graph · arrows run from subject to object. Focus or hover over a node or arrow for details; the evidence table follows.
Brackish water salinity-transition osmoregulation 16 nodes and 17 directed relationships. Labels and evidence are also available in the adjacent table. brackish water — receives → freshwater inflow; Evidence: PMID:15006771 receives brackish water — receives → seawater intrusion; Evidence: PMID:15006771 receives brackish water — has process → tidal mixing; Evidence: PMID:34544488 has process brackish water — has characteristic → water residence time; Evidence: PMID:15006771 has characteristic tidal mixing — creates → salinity variability; Evidence: PMID:34544488 creates freshwater inflow — mixes with → seawater intrusion; Evidence: PMID:22895159 mixes with brackish water — has characteristic → intermediate salinity; Evidence: PMID:22895159 has characteristic intermediate salinity — imposes → osmotic stress; Evidence: PMID:21663439 imposes salinity variability — intensifies → osmotic stress; Evidence: PMID:34544488 intensifies osmotic stress — selects for → osmoregulatory transport; Evidence: PMID:21663439; DOI:10.1186/s40168-024-01817-w selects for osmoregulatory transport — enables → compatible solute accumulation; Evidence: PMID:21663439; DOI:10.1186/s40168-024-01817-w enables osmoregulatory transport — enables → salt-in ion accumulation; Evidence: DOI:10.1186/s40168-024-01817-w enables osmotic stress — filters → freshwater bacterioplankton; Evidence: PMID:22895159 filters osmotic stress — filters → marine bacterioplankton; Evidence: PMID:15006771 filters intermediate salinity — drives → community turnover; Evidence: PMID:15006771; PMID:22895159 drives bacterial growth — establishes → estuarine bacterioplankton; Evidence: PMID:15006771 establishes water residence time — modulates → estuarine bacterioplankton; Evidence: PMID:15006771 modulates brackish water (HABITAT); brackish_water; ENVO:00002019 HABITAT brackish water freshwater inflow (ENVIRONMENTAL_FACTOR); freshwater_inflow ENVIRONMENTAL_FACTOR freshwater inflow seawater intrusion (ENVIRONMENTAL_FACTOR); seawater_intrusion ENVIRONMENTAL_FACTOR seawater intrusion tidal mixing (ENVIRONMENTAL_FACTOR); tidal_mixing ENVIRONMENTAL_FACTOR tidal mixing intermediate salinity (ENVIRONMENTAL_FACTOR); intermediate_salinity ENVIRONMENTAL_FACTOR intermediate salinity salinity variability (ENVIRONMENTAL_FACTOR); salinity_variability ENVIRONMENTAL_FACTOR salinity variability osmotic stress (ENVIRONMENTAL_FACTOR); osmotic_stress ENVIRONMENTAL_FACTOR osmotic stress osmoregulatory transport (TRAIT); osmoregulatory_transport TRAIT osmoregulatory transport compatible solute accumulation (PATHWAY); compatible_solute_accumulation PATHWAY compatible solute accumulation salt-in ion accumulation (PATHWAY); salt_in_strategy PATHWAY salt-in ion accumulation freshwater bacterioplankton (TAXON); freshwater_bacterioplankton TAXON freshwater bacterioplankton marine bacterioplankton (TAXON); marine_bacterioplankton TAXON marine bacterioplankton estuarine bacterioplankton (TAXON); estuarine_bacterioplankton TAXON estuarine bacterioplankton bacterial growth (COMMUNITY_PROCESS); bacterial_growth COMMUNITY_PROCESS bacterial growth water residence time (ENVIRONMENTAL_FACTOR); water_residence_time ENVIRONMENTAL_FACTOR water residence time community turnover (COMMUNITY_PROCESS); community_turnover COMMUNITY_PROCESS community turnover
brackish_water_salinity_transition_osmoregulation edges
EdgeSubjectPredicateObjectEvidence
brackish_water_receives_freshwater brackish water receives
River and freshwater inputs provide the low-salinity endmember of many brackish-water gradients.		 freshwater inflow PMID:15006771
Crump and colleagues sampled bacterioplankton along an estuary where freshwater and marine populations advected into brackish reaches.
brackish_water_receives_seawater brackish water receives
Marine intrusion supplies salts to freshwater, producing the high-salinity side of brackish transition zones.		 seawater intrusion PMID:15006771
The Parker River and Plum Island Sound study related shifts in bacterioplankton to salinity along a freshwater-to-marine estuary.
brackish_water_has_tidal_mixing brackish water has process
Brackish estuarine water is repeatedly mixed by tidal exchange with more saline marine water.		 tidal mixing PMID:34544488
Tee and colleagues sampled a river-to-sea system where tidal cycles periodically altered local salinity and nutrient conditions.
brackish_water_has_residence_time brackish water has characteristic
Brackish reaches retain water for a finite residence time that controls how long advected bacteria can grow before they are flushed.		 water residence time PMID:15006771
Crump and colleagues related estuarine bacterioplankton patterns to water residence time along the salinity gradient.
tidal_mixing_creates_salinity_variability tidal mixing creates
Tidal exchange periodically changes the local mixture of freshwater and seawater, making brackish-water salinity variable.		 salinity variability PMID:34544488
Tee and colleagues described river-to-sea transects where tidal cycles expose planktonic and benthic communities to fluctuating salinity.
freshwater_seawater_mixing_sets_intermediate_salinity freshwater inflow mixes with
Mixing between freshwater inflow and seawater intrusion sets a salinity range between freshwater and fully marine water.		 seawater intrusion PMID:22895159
Campbell and Kirchman measured bacterial diversity, structure, and potential growth rates across freshwater, brackish, and marine parts of Delaware Bay.
brackish_water_has_intermediate_salinity brackish water has characteristic
The defining physicochemical state of brackish water is salinity that lies between freshwater and marine water.		 intermediate salinity PMID:22895159
The Delaware Bay transect linked measured salinity to bacterial community composition across the freshwater-to-marine transition.
intermediate_salinity_imposes_osmotic_stress intermediate salinity imposes
Brackish salinity changes the osmotic pressure that bacterial cells must counter to retain water and turgor.		 osmotic stress PMID:21663439
Wood reviewed the homeostatic responses bacteria use as external osmolality changes.
salinity_variability_intensifies_osmotic_stress salinity variability intensifies
Fluctuating salinity repeatedly shifts external osmolality, increasing the need for dynamic osmotic adjustment.		 osmotic stress PMID:34544488
Tee and colleagues connected river-to-sea salinity variation with genomic signatures of osmoregulation in aquatic microbial communities.
osmotic_stress_selects_osmoregulatory_transport osmotic stress selects for
Bacteria in brackish gradients need membrane transport systems that import, export, or synthesize osmoprotective solutes as salinity changes.		 osmoregulatory transport PMID:21663439
The osmoregulation review describes uptake, release, and synthesis systems that maintain bacterial cell water balance. DOI:10.1186/s40168-024-01817-w
Wu and colleagues used estuarine metagenomes to identify salinity adaptation strategies across a short-residence-time estuary.
transport_enables_compatible_solutes osmoregulatory transport enables
Compatible-solute import and synthesis let cells counter osmotic stress while preserving cytoplasmic protein function.		 compatible solute accumulation PMID:21663439
Wood reviewed compatible-solute accumulation as a widespread bacterial response to hyperosmotic stress. DOI:10.1186/s40168-024-01817-w
Wu and colleagues reported salt-out adaptation based on compatible solutes along the estuarine salinity gradient.
transport_enables_salt_in_strategy osmoregulatory transport enables
Ion transport can support a salt-in strategy that balances osmotic pressure by accumulating inorganic ions.		 salt-in ion accumulation DOI:10.1186/s40168-024-01817-w
The estuarine metagenomic study contrasted inorganic-ion uptake with compatible-solute-based salt-out responses.
osmotic_stress_filters_freshwater_bacteria osmotic stress filters
Increasing salinity across the brackish transition filters freshwater bacterioplankton whose growth or activity declines in saltier water.		 freshwater bacterioplankton PMID:22895159
Campbell and Kirchman found that potential activity of freshwater taxa declined along the Delaware Bay salinity gradient.
osmotic_stress_filters_marine_bacteria osmotic stress filters
Freshened brackish reaches filter marine bacterioplankton that are adapted to fully saline water.		 marine bacterioplankton PMID:15006771
Crump and colleagues showed that marine and freshwater populations advected into estuarine waters and that distinct intermediate-salinity communities formed seasonally.
salinity_gradient_drives_community_turnover intermediate salinity drives
The estuarine salinity gradient restructures bacterioplankton composition across freshwater, brackish, and marine zones.		 community turnover PMID:15006771
Crump and colleagues related community-composition shifts to salinity, bacterial doubling time, and residence time. PMID:22895159
Campbell and Kirchman observed diversity, evenness, structure, and growth-potential changes along the Delaware Bay salinity gradient.
growth_and_residence_time_establish_estuarine_bacteria bacterial growth establishes
Brackish-adapted estuarine populations can establish when local bacterial growth is faster than hydrologic residence time and flushing.		 estuarine bacterioplankton PMID:15006771
The Parker River and Plum Island Sound study found a unique intermediate-salinity community when average doubling time was much shorter than water residence time.
residence_time_modulates_estuarine_establishment water residence time modulates
Hydrologic residence time modulates whether growing estuarine bacteria are retained or flushed through the brackish reach.		 estuarine bacterioplankton PMID:15006771
Crump and colleagues interpreted community formation as the combined result of growth time relative to estuarine water residence time.

Associated taxa

Taxa reported from this habitat, which is weaker than being characteristic of it. rank is out of pool: a high rank in a pool of thousands of near-tied scores is a weak claim. Entries corroborated by a second, independent source are listed first.

Taxa reported from this habitat
TaxonSourceRankPoolCorroborated
Cloacimonetes bacterium SCGC AAA252-E20 NCBITaxon:1046954 PREGO 1 1015
Cloacimonetes bacterium SCGC AAA252-F02 NCBITaxon:1046955 PREGO 2 1015
Cloacimonetes bacterium SCGC AAA252-G07 NCBITaxon:1046956 PREGO 3 1015
Cloacimonetes bacterium SCGC AAA252-G08 NCBITaxon:1046957 PREGO 4 1015
Cloacimonetes bacterium SCGC AAA252-I11 NCBITaxon:1046958 PREGO 5 1015
Cloacimonetes bacterium SCGC AAA252-I16 NCBITaxon:1046959 PREGO 6 1015
Cloacimonetes bacterium SCGC AAA252-K16 NCBITaxon:1046960 PREGO 7 1015
Cloacimonetes bacterium SCGC AAA252-L05 NCBITaxon:1046961 PREGO 8 1015
Cloacimonetes bacterium SCGC AAA252-L13 NCBITaxon:1046962 PREGO 9 1015
Cloacimonetes bacterium SCGC AAA252-M08 NCBITaxon:1046963 PREGO 10 1015
Cloacimonetes bacterium SCGC AAA252-N05 NCBITaxon:1046964 PREGO 11 1015
Cloacimonetes bacterium SCGC AAA252-N14 NCBITaxon:1046965 PREGO 12 1015
Cloacimonetes bacterium SCGC AAA252-N17 NCBITaxon:1046966 PREGO 13 1015
Cloacimonetes bacterium SCGC AAA252-O02 NCBITaxon:1046967 PREGO 14 1015
Cloacimonetes bacterium SCGC AAA252-O17 NCBITaxon:1046970 PREGO 15 1015
Cloacimonetes bacterium SCGC AAA252-P02 NCBITaxon:1046971 PREGO 16 1015
Cloacimonetes bacterium SCGC AAA252-P10 NCBITaxon:1046972 PREGO 17 1015
Cloacimonetes bacterium SCGC AAA252-P14 NCBITaxon:1046973 PREGO 18 1015
Cloacimonetes bacterium SCGC AAA255-B16 NCBITaxon:1046974 PREGO 19 1015
Cloacimonetes bacterium SCGC AAA255-C20 NCBITaxon:1046975 PREGO 20 1015
Cloacimonetes bacterium SCGC AAA255-L20 NCBITaxon:1046978 PREGO 21 1015
Acetothermia bacterium SCGC AAA255-C06 NCBITaxon:1046991 PREGO 22 1015
Microgenomates bacterium SCGC AAA255-J07 NCBITaxon:1047002 PREGO 23 1015
Omnitrophica bacterium SCGC AAA252-B19 NCBITaxon:1047006 PREGO 24 1015
Aminicenantes bacterium SCGC AAA252-B17 NCBITaxon:1047014 PREGO 25 1015

Showing 25 of 50 kept associations.

Also called

Curation

What a curator decided about this record, and why. A record built from several source concepts can carry one decision per concept.

  1. ADD_CAUSAL_GRAPH 2026-09-04 · codex

    Added a brackish-water salinity-transition osmoregulation graph backed by PMID:15006771, PMID:22895159, PMID:34544488, PMID:21663439, and DOI:10.1186/s40168-024-01817-w.

Provenance

Generated by scripts/seed_from_sources.py from the committed inventories in data/raw/. View the record.