{ "model": { "rank": 8166, "code": "thing-q272467", "model_id": "vr.tr.nitrogen-fixation", "name": "nitrogen fixation", "purpose": "Let an agent explain nitrogen fixation, relay biological, marine and industrial forms and their ecological and agricultural significance from biogeochemistry sources, describe marine nitrogen fixation, and distinguish fixation from nitrification, denitrification, nitrogen assimilation and fertiliser application.", "family": "Thing Registry", "category": "Activities and processes", "status": "research-draft", "kind": "thing", "plane": "ACT", "domain": "ACT.PRC", "industry": "", "version": "", "url": "/models/thing/q272467/", "tier": 2, "score": 52, "payload": { "layer": "wikidata", "aliases": [ "Marine nitrogen fixation" ], "aliasCount": 1, "merged": 1, "knownIn": 52, "facets": null, "markers": [], "lexicalClass": "", "senseRank": null, "alsoRegisteredAs": "vr.tr.nitrogen-fixation", "source": { "dataset": "wikidata", "item": "Q272467", "url": "https://www.wikidata.org/wiki/Q272467", "license": "CC0 1.0" } }, "research": { "vercy": "1.0-draft", "publication": { "status": "research-draft", "adjudicationStatus": "unreviewed", "publishableCanonical": false, "generatedAt": "2026-09-13T18:53:13Z", "providers": [ "Claude" ], "breadth": "written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify", "pass": 2, "wave": 4, "engine": "claude" }, "metaModel": { "id": "THING-Q272467", "registryId": "vr.tr.nitrogen-fixation", "name": "nitrogen fixation", "version": "0.2.0-wave.4", "entryKind": "thing", "family": "Thing Registry", "domain": [ "ACT.PRC" ], "status": "research-draft" }, "canonicalUrl": "https://ver.cy/models/thing/q272467/", "model": { "registry_id": "vr.tr.nitrogen-fixation", "name": "nitrogen fixation", "purpose": "Let an agent explain nitrogen fixation, relay biological, marine and industrial forms and their ecological and agricultural significance from biogeochemistry sources, describe marine nitrogen fixation, and distinguish fixation from nitrification, denitrification, nitrogen assimilation and fertiliser application.", "definition": "The conversion of atmospheric nitrogen gas into ammonia or related compounds usable by living organisms, performed biologically by nitrogen-fixing bacteria and archaea using the nitrogenase enzyme, including symbiotic rhizobia in legume root nodules, free-living soil microbes and marine cyanobacteria such as Trichodesmium in marine nitrogen fixation, and industrially by the Haber-Bosch process, with lightning fixing smaller amounts; nitrogen fixation is a key step in the nitrogen cycle.", "what_it_is_for": "Making nitrogen available to life.", "affordances": [ "explain biological and industrial fixation", "relay significance", "describe marine fixation", "distinguish related processes" ], "distinguishing_features": [ "N2 to ammonia", "Nitrogenase", "Biological and industrial", "Key nutrient input" ], "appearance": "Not a visible object; seen in legume root nodules.", "visual_identification": [ "Conversion of N2 to usable nitrogen", "Symbiotic fixation, free-living fixation, marine nitrogen fixation, Haber-Bosch process", "Nitrification oxidises ammonia; denitrification returns N2 to air; assimilation builds biomolecules; fertiliser is applied nitrogen" ], "physical_properties": [ { "quantity": "enzyme", "typical_range": "nitrogenase", "unit": "note", "note": "" }, { "quantity": "Haber-Bosch output", "typical_range": "about 150", "unit": "million tonnes N per year", "note": "estimates" }, { "quantity": "ATP per N2", "typical_range": "about 16", "unit": "count", "note": "biological fixation" } ], "families_and_kinds": [ "symbiotic fixation in legumes", "free-living soil fixation", "marine nitrogen fixation by cyanobacteria", "industrial Haber-Bosch fixation", "atmospheric fixation by lightning" ], "related_models": [ { "relation": "is a kind of", "target": "nitrogen cycle metabolic process", "why": "in registry terms" }, { "relation": "is catalysed by", "target": "nitrogenase", "why": "" }, { "relation": "is performed by", "target": "Rhizobium", "why": "in legume nodules" }, { "relation": "is industrialised as", "target": "Haber process", "why": "" } ], "identifiers": [ { "scheme": "GO", "value_or_pattern": "GO:0009399", "note": "nitrogen fixation" } ], "standards_and_regulation": [ "Fertiliser and nutrient pollution regulations" ], "failure_modes_and_hazards": [ "Nutrient pollution from industrial fixation", "Confusing fixation with nitrification", "Overstating engineered fixation in crops" ], "in_scope": [], "out_of_scope": [], "characteristics": [] }, "sources": [], "structure": { "bundles": [ { "id": "understand", "name": "Understand", "description": "What nitrogen fixation is.", "rationale": "Science.", "layers": [ { "id": "definition", "name": "Definition", "description": "Definition.", "findings": [ { "id": "definition-finding", "name": "Definition", "description": "Definition.", "questions": [ { "text": "What is nitrogen fixation, and how does it differ from nitrification, denitrification, assimilation and fertilising?", "kind": "definition" }, { "text": "Is the question about biology, oceans, agriculture or industry?", "kind": "boundary" } ] } ] }, { "id": "forms", "name": "Forms", "description": "Forms.", "findings": [ { "id": "forms-finding", "name": "Forms", "description": "Forms.", "questions": [ { "text": "What are symbiotic, free-living, marine, industrial and lightning fixation?", "kind": "definition" }, { "text": "Which entry fits the specific form?", "kind": "action" } ] } ] } ] }, { "id": "biology", "name": "Biology", "description": "Biology.", "rationale": "Science.", "layers": [ { "id": "nitrogenase", "name": "Nitrogenase", "description": "Nitrogenase.", "findings": [ { "id": "nitrogenase-finding", "name": "Nitrogenase", "description": "Nitrogenase.", "questions": [ { "text": "How does nitrogenase work, and why is it oxygen-sensitive?", "kind": "provenance" }, { "text": "Which references are standard?", "kind": "provenance" } ] } ] }, { "id": "symbiosis", "name": "Symbiosis", "description": "Symbiosis.", "findings": [ { "id": "symbiosis-finding", "name": "Symbiosis", "description": "Symbiosis.", "questions": [ { "text": "How do rhizobia and legumes form nodules?", "kind": "provenance" }, { "text": "Which sources are cited?", "kind": "provenance" } ] } ] } ] }, { "id": "earth", "name": "Earth", "description": "Global cycles.", "rationale": "Science.", "layers": [ { "id": "marine", "name": "Marine", "description": "Marine fixation.", "findings": [ { "id": "marine-finding", "name": "Marine", "description": "Marine.", "questions": [ { "text": "How do marine cyanobacteria fix nitrogen, and why does it matter for ocean productivity?", "kind": "provenance" }, { "text": "Which entry fits Trichodesmium?", "kind": "action" } ] } ] }, { "id": "industry", "name": "Industry", "description": "Industrial fixation.", "findings": [ { "id": "industry-finding", "name": "Industry", "description": "Industry.", "questions": [ { "text": "How did Haber-Bosch change agriculture and the nitrogen cycle, with impacts attributed?", "kind": "provenance" }, { "text": "Which entry fits Haber process?", "kind": "action" } ] } ] } ] }, { "id": "context", "name": "Context", "description": "Agriculture and research.", "rationale": "Context.", "layers": [ { "id": "agriculture", "name": "Agriculture", "description": "Agriculture.", "findings": [ { "id": "agriculture-finding", "name": "Agriculture", "description": "Agriculture.", "questions": [ { "text": "How do crop rotations with legumes use fixation?", "kind": "provenance" }, { "text": "Which entry fits crop rotation?", "kind": "action" } ] } ] }, { "id": "research", "name": "Research", "description": "Research.", "findings": [ { "id": "research-finding", "name": "Research", "description": "Research.", "questions": [ { "text": "What efforts aim to engineer fixation into cereals, and what is realistic, as researchers report?", "kind": "provenance" }, { "text": "Which entry fits synthetic biology?", "kind": "action" } ] } ] } ] } ] }, "openQuestions": [ "Should marine nitrogen fixation be a separate primary entry?", "How should biogeochemistry sources be linked?", "How should the Haber-Bosch process be linked?" ], "statistics": { "bundles": 4, "layers": 8, "findings": 8, "questions": 16 } }, "draft": { "generator": "vr.draft.v3", "status": "draft-generated", "researched": false, "archetype": "abstract concept", "method": "Written from the archetype playbook - what this kind of thing needs beyond identity and provenance - and from the structure that recurred across 6,333 models already researched by two engines. Applied to this entry by rule. No source was read for this thing and no claim here is researched. This entry carries no facets of its own, so they were inferred from its domain - a guess about a whole domain applied to one thing.", "facetsInferred": true, "nextPass": "A researcher replaces this draft with a sourced specification. Treat every sentence below as a proposal to argue with.", "purpose": "Give an agent a durable, checkable way to recognise a nitrogen fixation, record what state it is in, and decide what may be done with it.", "whatItIs": "Let an agent explain nitrogen fixation, relay biological, marine and industrial forms and their ecological and agricultural significance from biogeochemistry sources, describe marine nitrogen fixation, and distinguish fixation from nitrification, denitrification, nitrogen assimilation and fertiliser application.", "characteristics": { "substance": "activity", "origin": "conceptual", "agency": "inert" }, "whatYouCanDoWithIt": [ "observed and measured" ], "distinguishingFeatures": [ "Names folded into this entry, which a task may need to split apart again: Marine nitrogen fixation.", "1 finer distinctions are held as aliases rather than separate entries, because telling them apart needs a task that asks for it.", "Described in 52 Wikipedia languages, which is a measure of how widely the thing is known, not of how important it is." ], "openQuestionsForResearch": [ "Which of the bundles below does a real task actually need, and which are ceremony?", "What does this thing have that the facets do not capture at all?", "Which neighbouring kind is most often confused with a nitrogen fixation, and on what evidence are they told apart?" ], "whatItIsMadeOf": "something that happens over time", "physicalCharacter": [ "Does nothing on its own; everything it does, something else did to it.", "These come from the domain this entry sits in rather than from the entry itself, so treat them as a first guess about the whole domain applied to one thing." ], "whatCanBeDoneWithIt": [ "observe it, measure it, record its state" ], "howItIsRecognised": [ "Nothing to see. What is recognised is an instance of it, and which instances count is exactly what is argued about." ], "relatedModels": [ { "relation": "covers", "note": "Finer kinds folded into this entry because telling them apart needs a task that asks for it. Each is a model waiting to be split out when one does.", "targets": [ "Marine nitrogen fixation" ] } ], "standing": "Described in 52 Wikipedia languages, which measures how widely it is written about rather than how important or how common it is. 1 finer distinctions are held inside this entry as names rather than as separate models.", "structure": { "bundles": [ { "id": "identity-and-classification", "name": "Identity, naming and classification", "description": "How an agent tells one nitrogen fixation from another, and a nitrogen fixation from things that resemble it.", "rationale": "Recognition comes before every other claim. Without stable identity nothing else in the model can be trusted to be about the same thing twice.", "layers": [ { "id": "naming-and-identifiers", "name": "Names and identifiers", "description": "The names this thing goes by and the identifiers that survive translation and time.", "findings": [ { "id": "preferred-name-and-aliases", "name": "Preferred name, aliases and local names", "description": "Which name to use, which names mean the same thing, and which merely sound similar.", "questions": [ { "id": "preferred-name-and-aliases-q01", "text": "What identifies and describes the name of a nitrogen fixation, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "preferred-name-and-aliases-q02", "text": "Who or what asserted this about the name of a nitrogen fixation, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "preferred-name-and-aliases-q03", "text": "What may an agent decide or do once the name of a nitrogen fixation is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "stable-identifiers", "name": "Stable identifiers and external keys", "description": "Identifiers that keep pointing at this kind of thing across systems and languages.", "questions": [ { "id": "stable-identifiers-q01", "text": "What identifies and describes an identifier for a nitrogen fixation, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stable-identifiers-q02", "text": "Who or what asserted this about an identifier for a nitrogen fixation, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stable-identifiers-q03", "text": "What may an agent decide or do once an identifier for a nitrogen fixation is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "classification-and-granularity", "name": "Classification and granularity", "description": "Where a nitrogen fixation sits among kinds, and how finely a task needs to cut it.", "findings": [ { "id": "kind-and-parents", "name": "Kind, parents and neighbouring kinds", "description": "The classes this thing belongs to and the ones it is next to.", "questions": [ { "id": "kind-and-parents-q01", "text": "What identifies and describes the kind of a nitrogen fixation, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "kind-and-parents-q02", "text": "Who or what asserted this about the kind of a nitrogen fixation, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "kind-and-parents-q03", "text": "What may an agent decide or do once the kind of a nitrogen fixation is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "distinguishing-features", "name": "Distinguishing features", "description": "What separates a nitrogen fixation from the things most often confused with it.", "questions": [ { "id": "distinguishing-features-q01", "text": "What identifies and describes what distinguishes a nitrogen fixation, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "distinguishing-features-q02", "text": "Who or what asserted this about what distinguishes a nitrogen fixation, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "distinguishing-features-q03", "text": "What may an agent decide or do once what distinguishes a nitrogen fixation is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "state-and-lifecycle", "name": "State and lifecycle", "description": "The states a nitrogen fixation passes through and the events that move it between them.", "rationale": "Most decisions about a thing depend on what state it is in now, which is a claim with a time on it, not a property.", "layers": [ { "id": "lifecycle-stages", "name": "Lifecycle stages", "description": "From coming into existence to ceasing to be one of these.", "findings": [ { "id": "stages-and-transitions", "name": "Stages and transitions", "description": "The stages worth naming and what moves a nitrogen fixation between them.", "questions": [ { "id": "stages-and-transitions-q01", "text": "What identifies and describes the lifecycle of a nitrogen fixation, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stages-and-transitions-q02", "text": "Who or what asserted this about the lifecycle of a nitrogen fixation, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stages-and-transitions-q03", "text": "What may an agent decide or do once the lifecycle of a nitrogen fixation is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "observations-and-status", "name": "Observations and current status", "description": "What is observed about a nitrogen fixation, how often and by whom.", "findings": [ { "id": "observation-record", "name": "Observation record", "description": "How an observation of a nitrogen fixation is recorded so that it can be superseded rather than overwritten.", "questions": [ { "id": "observation-record-q01", "text": "What identifies and describes an observation of a nitrogen fixation, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "observation-record-q02", "text": "Who or what asserted this about an observation of a nitrogen fixation, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "observation-record-q03", "text": "What may an agent decide or do once an observation of a nitrogen fixation is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "process-and-outcome", "name": "Process, inputs and outcome", "description": "How a nitrogen fixation proceeds, what it needs and what it leaves behind.", "rationale": "An activity is known by its steps and its results, and both have to be recordable while it is still running.", "layers": [ { "id": "steps-and-sequence", "name": "Steps and sequence", "description": "The steps of a nitrogen fixation, their order and what may run in parallel.", "findings": [ { "id": "steps-and-preconditions", "name": "Steps, preconditions and completion", "description": "What has to be true before each step of a nitrogen fixation and what marks it done.", "questions": [ { "id": "steps-and-preconditions-q01", "text": "What identifies and describes a step of a nitrogen fixation, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "steps-and-preconditions-q02", "text": "Who or what asserted this about a step of a nitrogen fixation, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "steps-and-preconditions-q03", "text": "What may an agent decide or do once a step of a nitrogen fixation is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "inputs-and-results", "name": "Inputs, resources and results", "description": "What a nitrogen fixation consumes and what it produces.", "findings": [ { "id": "inputs-and-outputs", "name": "Inputs, outputs and side effects", "description": "The resources a nitrogen fixation takes and the results it leaves, wanted or not.", "questions": [ { "id": "inputs-and-outputs-q01", "text": "What identifies and describes the inputs and results of a nitrogen fixation, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "inputs-and-outputs-q02", "text": "Who or what asserted this about the inputs and results of a nitrogen fixation, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "inputs-and-outputs-q03", "text": "What may an agent decide or do once the inputs and results of a nitrogen fixation is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "definitions-in-contest", "name": "Definitions and who holds them", "description": "What nitrogen fixation is taken to mean, and by whom.", "rationale": "When a field disagrees about a concept, the disagreement is the content. A model that picks one definition silently destroys the information.", "layers": [ { "id": "competing-definitions", "name": "Competing definitions", "description": "The main readings and the traditions behind them.", "findings": [ { "id": "definition-map", "name": "Definitions and their holders", "description": "Each definition with the school or body that holds it.", "questions": [ { "id": "definition-map-q01", "text": "Which definitions of nitrogen fixation are in use, and which tradition or body holds each?", "kind": "definition" }, { "id": "definition-map-q02", "text": "What turns on the difference between them in practice?", "kind": "boundary" } ] } ] }, { "id": "operationalisation", "name": "Operationalisation", "description": "How it is measured or applied when it has to be.", "findings": [ { "id": "operational-record", "name": "Measures and proxies", "description": "Instruments and indicators used to stand in for it.", "questions": [ { "id": "operational-record-q01", "text": "How is nitrogen fixation operationalised or measured in practice, and by what instrument?", "kind": "measurement" }, { "id": "operational-record-q02", "text": "What does that operationalisation leave out, and when does that matter?", "kind": "boundary" } ] } ] } ] }, { "id": "instances-and-use", "name": "Instances, use and consequence", "description": "What counts as an instance of nitrogen fixation and what follows from calling something that.", "rationale": "Applying a concept is an act with consequences, so a model must say what the label licenses and what it does not.", "layers": [ { "id": "instances", "name": "What counts as an instance", "description": "Clear cases, borderline cases and non-cases.", "findings": [ { "id": "instance-tests", "name": "Tests for an instance", "description": "What would settle whether something falls under it.", "questions": [ { "id": "instance-tests-q01", "text": "What would settle whether something is an instance of nitrogen fixation?", "kind": "boundary" }, { "id": "instance-tests-q02", "text": "Which borderline cases are argued about, and on what grounds?", "kind": "definition" } ] } ] }, { "id": "consequence", "name": "Consequence of application", "description": "Rights, duties or decisions that follow from the label.", "findings": [ { "id": "consequence-record", "name": "What the label licenses", "description": "What an agent may do once something is classified this way.", "questions": [ { "id": "consequence-record-q01", "text": "What follows practically once something is treated as nitrogen fixation?", "kind": "action" }, { "id": "consequence-record-q02", "text": "What must an agent not infer from the label alone?", "kind": "action" } ] } ] } ] }, { "id": "provenance-and-evidence", "name": "Provenance, evidence and time", "description": "Where every claim about a nitrogen fixation came from and when it held.", "rationale": "A claim without a source and a time cannot be superseded, only overwritten, and an agent that overwrites loses the ability to explain itself.", "layers": [ { "id": "source-and-authority", "name": "Source and authority", "description": "Who said it, on what evidence, and how strongly.", "findings": [ { "id": "claim-provenance", "name": "Claim provenance and confidence", "description": "The authority behind each claim about a nitrogen fixation and how confident it is.", "questions": [ { "id": "claim-provenance-q01", "text": "What identifies and describes a claim about a nitrogen fixation, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "claim-provenance-q02", "text": "Who or what asserted this about a claim about a nitrogen fixation, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "claim-provenance-q03", "text": "What may an agent decide or do once a claim about a nitrogen fixation is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "time-and-versions", "name": "Time, versions and supersession", "description": "When a claim was true, when it was learnt, and what replaced it.", "findings": [ { "id": "validity-and-supersession", "name": "Validity period and supersession", "description": "How an old claim about a nitrogen fixation is retired without being erased.", "questions": [ { "id": "validity-and-supersession-q01", "text": "What identifies and describes the validity of a claim about a nitrogen fixation, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "validity-and-supersession-q02", "text": "Who or what asserted this about the validity of a claim about a nitrogen fixation, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "validity-and-supersession-q03", "text": "What may an agent decide or do once the validity of a claim about a nitrogen fixation is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] } ] }, "statistics": { "bundles": 6, "layers": 12, "findings": 14, "questions": 38 } } } }