Carbon cycle
The movement of carbon between the atmosphere, living things, oceans, and rocks.
At a glance
Key signals
30% cross fields · reaches 9 more
- Biology
- Geography
- Chemistry
- Explanation
- Examples
- Misconception
- Sourced relations 8
- Attribution
Dependencies
What this concept builds on and what it makes possible — derived from the atlas’s dependency, causal and structural relations, not from every related edge.
System context
Carbon cycleis aCycleEstablished
The carbon cycle is a cycle of matter through the Earth system.
Mechanism: Carbon flows from air to plants to animals to soil and back, returning again and again — the same repeating structure as any cycle.
- NOAA — The Carbon Cycle (educational resource) verification pendingmoderate evidence
Biodegradationis part ofCarbon cycleEstablished
biodegradation is part of the carbon cycle.
Mechanism: Biodegradation returns organic carbon to the cycle.
- Wikipedia (English & German editions) verifiedmoderate evidence
- Microbiology (OpenStax) (2016) verification pendingmoderate evidence
Carbon sinkis part ofCarbon cycleEstablished
carbon sink is part of Carbon cycle.
Mechanism: A carbon sink is the storing side of the carbon cycle — a reservoir like the ocean or a forest that absorbs more carbon than it releases.
- Wikidata verifiedmoderate evidence
Cellular respirationis part ofCarbon cycleEstablished
Respiration is part of the carbon cycle.
Mechanism: Respiration is a flow returning carbon to the atmosphere as CO₂.
- NOAA — The Carbon Cycle (educational resource) — demonstrates this case · needs-check · moderate evidence · Respiration returns carbon to the atmosphere, closing the biological loop of the carbon cycle.
Methanogenesisis part ofCarbon cycleEstablished
methanogenesis is part of the carbon cycle.
Mechanism: Methanogenesis is a microbial branch of the carbon cycle.
- Wikipedia (English & German editions) verifiedmoderate evidence
- Microbiology (OpenStax) (2016) verification pendingmoderate evidence
Structural role & consequence
Interpreted from the current atlas graph — what the connections mean, not just how many there are.
Removing this node lengthens the structural route between Methanogenesis and Stock from 2 to 8 steps (they stay connected — alternative routes exist).
structural · Structural removal simulation — not a historical or causal counterfactual.
30% of its relationships cross field boundaries, reaching 9 other disciplines — unusual in a discipline where most concepts stay within their field.
structural · Structural graph analysis — not a claim of importance, causation or history.
Currently dark in the atlas: no verified source · no key date stored · 8 of 10 of its relations lack claim-level evidence.
atlas representation · Describes the current Thinking OS representation, not the state of the world.
Exercises 3 annotated mental models — a concept that connects several thinking patterns.
curated · Curated annotations, not a derived measure.
cross-field
7 within-field, 3 cross-field
Strengths & constraints
Constraints
- Evidence coverage currently thin in the atlas — few of its relationships carry claim-level evidence. atlas representation
- No dated history stored — the atlas records no key date for this concept. atlas representation
Conditions
- Read structurally — most of its relationships carry no external evidence yet, so claims here are graph-derived. structural
Seen through each discipline
How this concept sits in each of its fields — derived from its real connections in the graph, not asserted.
Through this lens it connects to Photosynthesis, Cellular respiration, Nitrogen cycle and Cycle.
Through this lens it connects to Photosynthesis and Cellular respiration.
Through this lens it connects to Carbonate–silicate cycle.
Through this lens it connects to Biodegradation and Carbon capture and storage.
Carbon cycle is studied in this field.
What it looks like
Concrete cases that make this idea recognisable in the real world.
The carbon in your breath
A carbon atom you breathe out today might have been in a blade of grass last summer and could be taken up by a tree next year. The same carbon keeps moving between air, living things and soil.
Where you'll meet it
Journeys that walk you through this idea. You may recognise it from more than one.
Related ideas to explore
Concepts that look related but are not yet connected here — candidates for a connection to reason about, not established links.
This idea also appears in…
The same structure shows up in other disciplines. These are real recurrences drawn from the graph — a starting point for asking “what carries over, and what changes?”
Stocks and flows37 disciplines · 34 concepts
Feedback loop43 disciplines · 46 concepts
Conservation7 disciplines · 8 concepts
Concepts
- Nitrogen cycleEcology
shares a mental model · shares a mental model · explicitly analogous
shares a mental model · shares a mental model
shares a mental model · shares a mental model
shares a mental model · shares a mental model
- Biogeochemical cycleEarth & Space Sciences
shares a mental model · shares a mental model
shares a mental model · crosses a discipline boundary
Curriculum alignment
Austria · AHS Unterstufe (Sekundarstufe I) · Biologie und Umweltbildung
Appears in official curriculum objectives
Understand that materials and energy carriers largely move through closed cycles in ecological systems, and that human activity can alter these cycles. · 1.–4. Klasse (zentrales fachliches Konzept)
Exact wording: „Lebewesen sind an Stoff- und Energieumwandlung gebunden. Organische Verbindungen werden vorwiegend von Pflanzen aufgebaut. In ökologischen Systemen durchlaufen Baustoffe und Energieträger vorwiegend geschlossene Kreisläufe. Menschliche Aktivitäten können solche Kreisläufe verändern.“
How this official objective connects, through canonical knowledge, to what a learner actually does — each link is real data, never a coverage claim.
Canonical concept
- How each concept relates to the objective
- named — The objective's own wording names this concept.
- required — You must grasp this concept to meet the objective.
- supports — Helps meet the objective, but is not strictly required.
Relations & mental models
2 canonical relations connect these concepts
- Photosynthesis is part of Carbon cycle
- Producer (autotroph) depends on Photosynthesis
Mental models these concepts carry: Stocks and flows ×3Energy transformation ×2ConservationFeedback loopNetworksJourney
Journeys that walk concepts relevant to this objective
Activity → Observable evidence
4 activities engage these concepts
identified a missing linkpredicted an effectpredicted a relationshippredicted a what-if outcomeWhat those activities are designed to make observable — designed intent, not proof of learning.
Provenance
- Authority
- BMBWF
- Document
- BGBl. II Nr. 1/2023
- Section
- Anlage A zu Art. 4 · Biologie und Umweltbildung · Zentrale fachliche Konzepte, „Stoff- und Energieumwandlung“ (S. 111)
- Version
- Stammfassung, Kundmachung 2. Jänner 2023
- School type
- AHS Unterstufe (Sekundarstufe I)
- Subject
- Biologie und Umweltbildung
- Stage
- lower-secondary
- Accessed
- 2026-09-17
✓ Source verified
Understand the global carbon cycle, CO₂ input into the atmosphere, and climate change. · 4. Klasse (8. Schulstufe)
Exact wording: „Globaler Kohlenstoffkreislauf, CO₂-Eintrag in die Atmosphäre, Klimawandel“
How this official objective connects, through canonical knowledge, to what a learner actually does — each link is real data, never a coverage claim.
Canonical concept
Carbon cycle namedCarbon dioxide (CO₂) namedAtmosphere namedClimate namedGreenhouse effect requiredFossil fuels required- How each concept relates to the objective
- named — The objective's own wording names this concept.
- required — You must grasp this concept to meet the objective.
Relations & mental models
3 canonical relations connect these concepts
- Carbon dioxide (CO₂) amplifies Greenhouse effect
- Carbon dioxide (CO₂) is part of Atmosphere
- Fossil fuels causes Carbon dioxide (CO₂)
Mental models these concepts carry: Feedback loop ×3Stocks and flows ×3ConservationActivity → Observable evidence
5 activities engage these concepts
explained a relationshiptransferred a patternpredicted a relationshippredicted a what-if outcomeWhat those activities are designed to make observable — designed intent, not proof of learning.
“Greenhouse effect” and “fossil fuels” are not named verbatim in this objective, but are the mechanism required to understand it.
Provenance
- Authority
- BMBWF
- Document
- BGBl. II Nr. 1/2023
- Section
- Anlage A zu Art. 4 · Biologie und Umweltbildung · Anwendungsbereiche, 4. Klasse (S. 113)
- Version
- Stammfassung, Kundmachung 2. Jänner 2023
- School type
- AHS Unterstufe (Sekundarstufe I)
- Subject
- Biologie und Umweltbildung
- Stage
- lower-secondary
- Accessed
- 2026-09-17
✓ Source verified
Analyse ecosystems with their material and energy cycles, environmental factors and succession. · 6. Klasse · 4. Semester (Kompetenzmodul 4)
Exact wording: „Ökosysteme (Stoff- und Energiekreisläufe, Umweltfaktoren, Sukzession, Konvergenzerscheinungen)“
How this official objective connects, through canonical knowledge, to what a learner actually does — each link is real data, never a coverage claim.
Canonical concept
- How each concept relates to the objective
- named — The objective's own wording names this concept.
- supports — Helps meet the objective, but is not strictly required.
Relations & mental models
1 canonical relations connect these concepts
- Food chain depends on Producer (autotroph)
Mental models these concepts carry: Energy transformation ×2Networks ×2Stocks and flows ×2ConservationFeedback loopActivity → Observable evidence
1 activities engage these concepts
predicted a what-if outcomeWhat those activities are designed to make observable — designed intent, not proof of learning.
Provenance
- Authority
- BMBWF
- Document
- Lehrpläne AHS (RIS Gesetzesnummer 10008568, Stammfassung BGBl. Nr. 88/1985)
- Section
- Anlage A · Biologie und Umweltbildung · Oberstufe, 6. Klasse, Kompetenzmodul 4
- Version
- Bundesrecht konsolidiert, Fassung vom 2026-09-17 (zuletzt geändert BGBl. II Nr. 204/2024); Anlage A in Kraft aufsteigend ab 5. Kl. 2024
- School type
- AHS Oberstufe
- Subject
- Biologie und Umweltbildung
- Stage
- upper-secondary
- Accessed
- 2026-09-17
✓ Source verified
Analyse the Earth's geo-ecosystems — explain interactions of climate, relief, soil, water and vegetation and their human transformation. · 5. Klasse (1. und 2. Semester)
Exact wording: „Geoökosysteme der Erde analysieren: Klimadaten in Diagramme umsetzen; Klimagliederungen der Erde vergleichen und hinterfragen; Wechselwirkungen von Klima, Relief, Boden, Wasser und Vegetation analysieren; Geoökosysteme und deren anthropogene Überformung erklären“
How this official objective connects, through canonical knowledge, to what a learner actually does — each link is real data, never a coverage claim.
Canonical concept
- How each concept relates to the objective
- named — The objective's own wording names this concept.
- supports — Helps meet the objective, but is not strictly required.
- context — Enrichment or framing around the objective.
Relations & mental models
Mental models these concepts carry: Feedback loop ×2ConservationStocks and flowsActivity → Observable evidence
2 activities engage these concepts
transferred a patternpredicted a what-if outcomeWhat those activities are designed to make observable — designed intent, not proof of learning.
Provenance
- Authority
- BMBWF
- Document
- Lehrpläne AHS (RIS Gesetzesnummer 10008568, Stammfassung BGBl. Nr. 88/1985)
- Section
- Anlage A · Geographie und wirtschaftliche Bildung · Oberstufe, 5. Klasse (Geoökosysteme)
- Version
- Bundesrecht konsolidiert, Fassung vom 2026-09-17 (zuletzt geändert BGBl. II Nr. 204/2024)
- School type
- AHS Oberstufe
- Subject
- Geographie und wirtschaftliche Bildung
- Stage
- upper-secondary
- Accessed
- 2026-09-17
✓ Source verified
Pilot slice: mapped to selected official objectives, not a coverage claim. Concept identity is canonical and never redefined by a curriculum.
Carbon moves in a cycle: photosynthesis takes CO₂ out of the air, respiration and burning put it back. The balance of these flows shapes how much CO₂ is in the atmosphere.
Mental models at work here
Stocks and flows
A stock is an amount that accumulates; flows are the rates that add to or drain it. The stock changes only when inflow and outflow differ.
Think of a bathtub: the water level (stock) rises or falls depending on the tap (inflow) and the drain (outflow).
Feedback loop
A loop where an effect feeds back to change its own cause. Reinforcing loops amplify change; balancing loops resist it.
Ask: does the result push the system further in the same direction, or pull it back?
Conservation
Some quantity stays constant no matter how a system rearranges — it can move or transform but is never created or destroyed.
Track the conserved quantity like an accountant: whatever leaves here must show up there. A missing amount means you've missed a path.
- Connects 10 other ideas across 6 disciplines.
- A cross-disciplinary bridge — its connections reach into 9 other fields.
- Most of its connections are of the “Kind & structure” kind.
- It exercises 3 reusable thinking patterns.
- It supports 4 curriculum objectives.
- It features in 1 learning journey.
Derived from the graph’s real structure — observations, not a score.
Sources
- NOAA — The Carbon Cycle (educational resource) verification pendingmoderate evidence