{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.dissolved-organic-carbon","code":"thing-q449096","url":"https://ver.cy/models/thing/q449096/","name":"dissolved organic carbon","alternateNames":[],"kind":"thing","status":"published","version":"0.1.0-research.1","language":"en","classifiers":{"family":"Thing Registry","category":"Physical world and living systems","entryKind":"thing","plane":"PHY","domain":["PHY.MAT"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"Dissolved organic carbon (DOC) is the carbon contained in organic matter in water that passes a specified filter, commonly with a nominal pore size of 0.45 micrometres, making it an operationally defined fraction rather than a single chemical substance.","purpose":"Enable an agent to recognise dissolved organic carbon as an operationally defined carbon fraction, assess whether its measurements are comparable, and judge its potential transport, transformation and treatment behaviour.","scope":{"in":["Operational definition of the dissolved fraction, including filtration and sample preparation","DOC concentration, uncertainty and measurement basis","Organic composition and properties relevant to reactivity","Sources, transport and transformations of DOC","Evidence supporting decisions about DOC monitoring or removal"],"out":["Dissolved inorganic carbon, including carbonate-system modelling","Particulate organic carbon retained by the selected separation procedure","Complete dissolved organic matter composition beyond its carbon-related characterisation","Whole-water ecosystem or catchment models","Treatment equipment design and operating procedures","Identity and hazard classification of individual organic compounds"],"boundaries":[]},"distinguishingFeatures":["The reported quantity concerns organic carbon assigned to an aqueous dissolved fraction; the separation method must accompany that assignment.","DOC expresses carbon mass rather than the total mass of dissolved organic matter.","A DOC result must distinguish organic carbon from dissolved inorganic carbon through the analytical procedure.","DOC and particulate organic carbon are separated operationally; the treatment of colloids depends on the selected procedure.","DOC is a mixture-level fraction rather than a single chemical substance with a universal molecular formula, purity or set of physical constants."],"structure":{"bundles":[{"id":"fraction-identity","name":"Fraction identity","description":"Defines which organic carbon is assigned to DOC and distinguishes it from neighbouring carbon and organic-matter quantities.","layers":[{"id":"dissolved-boundary","name":"Dissolved boundary","description":"Records the separation procedure that establishes membership in the dissolved fraction.","findings":[{"id":"operational-membership","name":"Operational membership","description":"Identify the procedure used to assign carbon-bearing material to the dissolved fraction, including unresolved colloidal membership.","questions":[{"text":"What separation procedure, filter material and nominal pore size define DOC for this observation?","id":"operational-membership-q01","kind":"definition"},{"text":"How does this procedure allocate colloidal organic material between dissolved and retained fractions?","id":"operational-membership-q02","kind":"boundary"}]}]},{"id":"carbon-basis","name":"Carbon basis","description":"Distinguishes DOC from total dissolved organic matter and other carbon fractions.","findings":[{"id":"quantity-distinction","name":"Quantity distinction","description":"Require an explicit carbon basis and a clear relationship to inorganic, particulate and total organic carbon measurements.","questions":[{"text":"Does the reported value express organic carbon mass, total organic matter mass or a proxy signal?","id":"quantity-distinction-q01","kind":"definition"},{"text":"How are dissolved inorganic carbon and particulate organic carbon excluded or accounted for?","id":"quantity-distinction-q02","kind":"boundary"}]}]}]},{"id":"measurement-validity","name":"Measurement validity","description":"Connects a DOC result to its sample history, analytical coverage and uncertainty.","layers":[{"id":"sample-history","name":"Sample history","description":"Captures handling steps that may change the amount or composition of the sampled fraction.","findings":[{"id":"handling-integrity","name":"Handling integrity","description":"Establish whether collection, filtration, storage and preservation support the intended interpretation.","questions":[{"text":"When and how were collection, filtration, preservation and analysis performed?","id":"handling-integrity-q01","kind":"provenance"},{"text":"What blanks or handling checks assess contamination, sorption or alteration during storage?","id":"handling-integrity-q02","kind":"measurement"}]}]},{"id":"analytical-coverage","name":"Analytical coverage","description":"Defines what the carbon analysis measures and how confidently it does so.","findings":[{"id":"result-interpretability","name":"Result interpretability","description":"Associate concentration with the analytical method, carbon-fraction coverage and quality evidence.","questions":[{"text":"Which analytical method was used, and how does it handle inorganic carbon and purgeable organic carbon?","id":"result-interpretability-q01","kind":"measurement"},{"text":"What calibration, recovery, replicate precision, reporting limit and uncertainty support the reported concentration?","id":"result-interpretability-q02","kind":"measurement"},{"text":"Which differences in preparation or analytical coverage prevent direct comparison with another DOC result?","id":"result-interpretability-q03","kind":"boundary"}]}]}]},{"id":"composition-and-reactivity","name":"Composition and reactivity","description":"Characterises properties of the DOC mixture that concentration alone cannot establish.","layers":[{"id":"mixture-characterisation","name":"Mixture characterisation","description":"Links compositional and optical observations to the portion of DOC they actually characterise.","findings":[{"id":"characterisation-coverage","name":"Characterisation coverage","description":"Distinguish whole-fraction carbon measurements from selective signals or recovered subfractions.","questions":[{"text":"Which optical, molecular or fractionation measurements characterise this DOC, and what portion of the mixture do they represent?","id":"characterisation-coverage-q01","kind":"measurement"},{"text":"What evidence supports interpreting these signals as composition indicators in this aqueous matrix?","id":"characterisation-coverage-q02","kind":"boundary"}]}]},{"id":"conditional-reactivity","name":"Conditional reactivity","description":"Records biological and photochemical responses under specified conditions.","findings":[{"id":"reactivity-evidence","name":"Reactivity evidence","description":"Treat lability and persistence as conclusions tied to a test, timescale and environment.","questions":[{"text":"What DOC change was measured under specified incubation or irradiation conditions, duration and controls?","id":"reactivity-evidence-q01","kind":"measurement"},{"text":"How far can the observed response be applied to the intended environment or decision timescale?","id":"reactivity-evidence-q02","kind":"action"}]}]}]},{"id":"origin-transport-and-decisions","name":"Origin, transport and decisions","description":"Relates DOC observations to source hypotheses, movement, transformations and interventions.","layers":[{"id":"sources-and-movement","name":"Sources and movement","description":"Connects source attribution and carbon transport to observations at defined spatial and temporal boundaries.","findings":[{"id":"source-and-flux-evidence","name":"Source and flux evidence","description":"Keep source hypotheses distinct from measured concentrations and quantify transport only with compatible hydrological evidence.","questions":[{"text":"Which candidate sources are supported by tracers, endmember observations or other evidence, and which remain unresolved?","id":"source-and-flux-evidence-q01","kind":"provenance"},{"text":"Are water-flow and DOC measurements sufficiently aligned in time and space to estimate carbon flux across the chosen boundary?","id":"source-and-flux-evidence-q02","kind":"measurement"}]}]},{"id":"change-and-intervention","name":"Change and intervention","description":"Supports interpretation of DOC changes and evaluation of monitoring or removal actions.","findings":[{"id":"change-attribution","name":"Change attribution","description":"Require evidence to distinguish dilution, mineralisation, production and transfer to other fractions.","questions":[{"text":"What accompanying observations distinguish dilution from DOC transformation or transfer to particulate or sorbed material?","id":"change-attribution-q01","kind":"measurement"},{"text":"Where did carbon leaving the measured DOC fraction go, and is that fate measured or inferred?","id":"change-attribution-q02","kind":"boundary"}]},{"id":"decision-specific-evidence","name":"Decision-specific evidence","description":"Tie monitoring and treatment judgments to a stated objective and evidence beyond bulk concentration where needed.","questions":[{"text":"What matrix-specific evidence shows that a proposed action changes DOC in a way relevant to the stated objective?","id":"decision-specific-evidence-q01","kind":"action"},{"text":"Which additional measurements are needed before using DOC as an indicator of treatment performance, oxygen demand or disinfection by-product formation potential?","id":"decision-specific-evidence-q02","kind":"action"}]}]}]},{"id":"evidence-and-external-alignment","name":"Evidence and external alignment","description":"What the world already says about this thing, gathered so the model can be checked against it.","layers":[{"id":"reported-evidence","name":"Reported evidence","description":"Findings from the breadth pass, kept separate from the structural claims.","findings":[{"id":"evidence-confidence-notes","name":"Check these first","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these check these first hold for the sense of dissolved organic carbon this model covers, and on what evidence?","id":"evidence-confidence-notes-q01","kind":"provenance"}]},{"id":"evidence-kinds","name":"Kinds and varieties","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these kinds and varieties hold for the sense of dissolved organic carbon this model covers, and on what evidence?","id":"evidence-kinds-q01","kind":"provenance"}]},{"id":"evidence-standards-and-regulation","name":"Standards and regulation","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these standards and regulation hold for the sense of dissolved organic carbon this model covers, and on what evidence?","id":"evidence-standards-and-regulation-q01","kind":"provenance"}]},{"id":"evidence-real-world-use","name":"Real-world use","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these real-world use hold for the sense of dissolved organic carbon this model covers, and on what evidence?","id":"evidence-real-world-use-q01","kind":"provenance"}]},{"id":"evidence-measurements","name":"Typical measurements","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these typical measurements hold for the sense of dissolved organic carbon this model covers, and on what evidence?","id":"evidence-measurements-q01","kind":"provenance"}]},{"id":"evidence-failure-modes-and-hazards","name":"Failure modes and hazards","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these failure modes and hazards hold for the sense of dissolved organic carbon this model covers, and on what evidence?","id":"evidence-failure-modes-and-hazards-q01","kind":"provenance"}]},{"id":"evidence-regional-variation","name":"Regional variation","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these regional variation hold for the sense of dissolved organic carbon this model covers, and on what evidence?","id":"evidence-regional-variation-q01","kind":"provenance"}]},{"id":"evidence-neighbours","name":"Neighbouring kinds and how to tell them apart","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these neighbouring kinds and how to tell them apart hold for the sense of dissolved organic carbon this model covers, and on what evidence?","id":"evidence-neighbours-q01","kind":"provenance"}]}]}]}]},"agentConduct":{"may":["Measure and report DOC with the filtration method and pore size used.","Explain DOC trends in water bodies from monitoring data."],"mustNot":["Report DOC values without stating the operational method that defines them.","Alter or omit monitoring results to hide pollution or water treatment problems.","Present DOC as a measure of safety for drinking water on its own."],"requiresHuman":["Changing water treatment because of a DOC result."]},"ethics":{"considerations":["High organic carbon can form harmful by-products when drinking water is disinfected.","Monitoring data informs public decisions and must be honest."],"affectedParties":["Drinking water consumers","Aquatic ecosystems","Water utilities"]},"owners":{"steward":"Nobody owns it; water utilities and environmental agencies answer for monitoring.","roles":[],"masterSystems":["Environmental agency water quality databases"]},"relations":[{"target":"Q11770757","type":"parent","note":"registry parent class"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.dissolved-organic-carbon","Wikidata: Q449096 (https://www.wikidata.org/wiki/Q449096)"]},"properties":{"applicability":"required","items":["Aqueous matrix: Freshwater, seawater, groundwater, porewater, wastewater, aqueous extract or other specified matrix","Dissolved-fraction boundary: Separation method; filter material and nominal pore size in µm where applicable","DOC concentration: mg C/L or µmol C/L, with uncertainty and reporting limit","Analytical carbon coverage: Method-defined DOC coverage, including handling of inorganic and purgeable organic carbon","Sample integrity: Documented preservation and holding conditions; verified, compromised or unknown integrity","Optical character: Specified absorbance or fluorescence measurements, with wavelength, units and normalisation","Biodegradable fraction: mg C/L or percentage of initial DOC under a specified incubation protocol","Source attribution: Links to candidate sources, supporting observations and attribution confidence","DOC flux: g C/day or kg C/day across a specified boundary and interval"]},"recognition":{"applicability":"required","items":["Often shows as brown or tea-coloured water, though colour alone does not measure it."]},"capabilities":{"applicability":"required","items":["Determine whether a reported result qualifies as DOC under a documented operational definition.","Compare DOC observations after checking separation methods, analytical coverage, units and sample handling.","Identify additional analyses needed to assess composition, origin or reactivity.","Estimate DOC transport when concentration and compatible water-flow observations are available.","Evaluate observed DOC changes against dilution, transformation and transfer between fractions.","Assess DOC removal or monitoring options using matrix-specific evidence."]},"hazards":{"applicability":"required","items":["Reacts with chlorine to form disinfection by-products.","Different methods give results that are not comparable."]},"interfaces":{"applicability":"required","items":["ISO 8245, Water quality: guidelines for the determination of total organic carbon and dissolved organic carbon, International Organization for Standardization."]},"context":{"applicability":"required","items":["Dissolved organic carbon is measured in rivers, lakes, groundwater, seawater and water treatment systems to characterize organic carbon in the filtered water fraction.","It supports studies of carbon transport, microbial activity and oxygen consumption during organic matter degradation.","Water treatment assessments use it to evaluate organic loading and potential treatment challenges, with comparisons requiring compatible filtration and analytical methods."]}},"sources":[{"title":"Wikidata item Q449096: dissolved organic carbon","url":"https://www.wikidata.org/wiki/Q449096","note":"identity and sense of the item"},{"title":"Wikipedia: Dissolved organic carbon","url":"https://en.wikipedia.org/wiki/Dissolved_organic_carbon","note":"general description of the item"}],"openQuestions":["Which operational definitions and analytical standards should be supported for the intended matrices, particularly their handling of colloids and purgeable organic carbon?","How should aqueous extracts of soils or solids be related to environmental DOC without implying that extraction reproduces an in situ dissolved pool?","Which compositional or optical indicators have sufficiently validated relationships to DOC behaviour in each intended matrix?","What evidence and timescale are required before describing a DOC fraction as biodegradable, persistent or effectively removed?","Which existing Vercy models cover dissolved organic matter, other carbon fractions and aquatic carbon cycling, and where should this model link to them?"],"resources":{"spec":"/models/things/publications/thing-q449096/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q449096/spec.json"],"providers":["Codex"],"researchStatus":"unreviewed","generatedAt":"2026-09-12T09:14:56Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"filled","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-07T10:10:31+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass"},"score":1.0}}