Concept · environmental-science
Carbon cycle
10 studies1 discovery
Carbon-cycle studies track how carbon moves through plants, soils, lakes or the atmosphere under environmental change.
It is the biogeochemical core of climate–ecosystem science.
Studies
10
Findings
5
7 supporting · 0 challenging · 0 qualifying citations
Open tensions
1
Currently
What we know
- This library holds 10 empirical papers on carbon cycle with measured outcomes rather than reviews.
- Vascular plants raised peatland respiration 145% vs bare peat; warming increased fluxes 111% on bare and 63% with dwarf-shrubs and shifted 14C toward older carbon where shrubs were present.
- Canopy-applied 15N is recovered aboveground about three times more than soil-applied N.
- At a Swedish subarctic treeline, shrub and birch plots stored far less soil organic carbon than nearby heaths and respired that carbon faster, implying woody expansion can accelerate soil C loss.
- Across a Swedish stream and two lakes, the most water-loving DOM fractions lost 12–25% of DOC in 150 days versus 6–15% for hydrophobic fractions.
Largest unresolved question
A mesocosm, a peat profile or a shrub plot does not close the global carbon budget.
Common misconceptions
More nitrogen always means more stored carbon.
Canopy vs soil uptake, seasonality and vegetation type change the C:N outcome.
Related
Claim ledger
What the evidence shows
Drawn from 10 studies in this library. Mix labels say which citation roles are present; they are not a strength score. Supports means evidence for a finding; Challenges means evidence against a stated position; Qualifies marks scope.
This library holds 10 empirical papers on carbon cycle with measured outcomes rather than reviews.
- Shrubs help warming unlock ancient peat carbon
- Canopy nitrogen and tree carbon uptake
- Shrubs and trees empty subarctic soil carbon
Study Role Design N Population Outcome Shrubs help warming unlock ancient peat carbon Supports OtherFactorial warming × vegetation-removal peatland experiment with 14C-partitioned respiration Treatment-level replicates n=3 for 14C/CO2 sampling; exact plot census not a single primary N in stored text Peatland plots with bare, bryophyte, graminoid, dwarf-shrub, and full vegetation treatments Ecosystem respiration flux and age (14C) under warming and vascular-plant presence Canopy nitrogen and tree carbon uptake Supports Animal / in-vitro15N tracer mesocosm comparing canopy vs soil nitrogen targeting in Sitka spruce Potted Sitka spruce mesocosms; mean aboveground biomass 370 g/tree — exact tree N not primary in stored text Potted Sitka spruce trees Aboveground and wood recovery of canopy-applied vs soil-applied 15N Shrubs and trees empty subarctic soil carbon Supports Cross-sectionalSpace-for-time forest–heath transects comparing SOC and respiration under shrub expansion N=19 · 12 Abisko + 7 Vassijaure forest–heath transects Subarctic treeline heath, shrub, and birch forest plots in northern Sweden Soil organic carbon stocks and respiration rates across vegetation types Vascular plants raised peatland respiration 145% vs bare peat; warming increased fluxes 111% on bare and 63% with dwarf-shrubs and shifted 14C toward older carbon where shrubs were present.
Canopy-applied 15N is recovered aboveground about three times more than soil-applied N.
At a Swedish subarctic treeline, shrub and birch plots stored far less soil organic carbon than nearby heaths and respired that carbon faster, implying woody expansion can accelerate soil C loss.
Across a Swedish stream and two lakes, the most water-loving DOM fractions lost 12–25% of DOC in 150 days versus 6–15% for hydrophobic fractions.
Debates
Tensions and limits
Some items are genuine disagreements on the same question. Others mark different assays, populations, or outcomes.
A mesocosm, a peat profile or a shrub plot does not close the global carbon budget.
A mesocosm, a peat profile or a shrub plot does not close the global carbon budget.
Study Role Design N Population Outcome Shrubs help warming unlock ancient peat carbon Supports OtherFactorial warming × vegetation-removal peatland experiment with 14C-partitioned respiration Treatment-level replicates n=3 for 14C/CO2 sampling; exact plot census not a single primary N in stored text Peatland plots with bare, bryophyte, graminoid, dwarf-shrub, and full vegetation treatments Ecosystem respiration flux and age (14C) under warming and vascular-plant presence Canopy nitrogen and tree carbon uptake Supports Animal / in-vitro15N tracer mesocosm comparing canopy vs soil nitrogen targeting in Sitka spruce Potted Sitka spruce mesocosms; mean aboveground biomass 370 g/tree — exact tree N not primary in stored text Potted Sitka spruce trees Aboveground and wood recovery of canopy-applied vs soil-applied 15N
PaperFren reads this as a limit on how far one study travels — different assays, populations, or outcomes — not a forced fight between papers.
Timeline
How understanding moved
Study years are when the paper was published. Evidence edits are dated changes to this page's claims. Explanations are when PaperFren added a Discovery — not a claim that the science happened that day.
2026
Concept page published
Carbon cycle
- More plant species meant more soil carbon — through microbial biomass, not efficiency
Change log
What changed
Dated edits to this page's evidence: studies added or removed from a claim, claims added or withdrawn, and new explanations tagged here. Coverage edits are distinct from reviewed research changes and corrections. Dates record PaperFren updates; study publication dates appear in the timeline.
- Coverage updated · Concept page published
Papers
10 studies in this library bear on Carbon cycle, ordered by citations.
- Plant diversity builds soil carbon via microbes
Higher plant species richness raises soil organic carbon by boosting microbial growth, biomass, and fungal necromass, not carbon-use efficiency.
- Shrubs and trees empty subarctic soil carbon
At a Swedish subarctic treeline, shrub and birch plots stored far less soil organic carbon than nearby heaths and respired that carbon faster, implying woody expansion can accelerate soil C loss.
- Shrubs help warming unlock ancient peat carbon
Vascular plants raised peatland respiration 145% vs bare peat; warming increased fluxes 111% on bare and 63% with dwarf-shrubs and shifted 14C toward older carbon where shrubs were present.
- Hydrophilic freshwater DOM biodegrades fastest
Across a Swedish stream and two lakes, the most water-loving DOM fractions lost 12–25% of DOC in 150 days versus 6–15% for hydrophobic fractions.
- Arctic food-web carbon is going isotopically light
Across 17 Arctic regions, water-column POC δ13C fell 0.149‰ per year—far faster than DIC/CO2 (0.011‰/yr)—and seal and whale tissues tracked the decline.
- Canopy nitrogen and tree carbon uptake
Canopy-applied 15N is recovered aboveground about three times more than soil-applied N.
- As acid rain fades, climate steers water browning
DOC rose at 383 of 426 northern sites since 1990; early increases tracked falling sulfate, while later increases are nearly half climate-driven.
- Dark lakes change how microbes eat land carbon
In a dark Ontario lake, more aromatic terrestrial organic matter lowered bacterial production and slightly raised CO2.
Show 2 more studiesShow fewer studies
- Warm soils change microbes, not Q10 of respiration
Along a >31°C geothermal gradient in New Zealand, bacterial and fungal communities shifted but MMRT temperature-sensitivity of soil respiration showed no thermal adaptation.
- Amazon forest carbon is highly seasonal
An Amazon forest stored about four times more carbon in the dry season than the wet season.
Compare studies
Select 2–10 studies. Design and N are labels, not a ranking.
Nothing selected yet.
Questions
What is still open
A mesocosm, a peat profile or a shrub plot does not close the global carbon budget.
Ask PaperFren about Carbon cycle
Study this conceptflashcards and short-answer questions
What does carbon cycle mean in this library?
Carbon-cycle studies track how carbon moves through plants, soils, lakes or the atmosphere under environmental change.
Name one empirical finding from the carbon cycle papers.
Vascular plants raised peatland respiration 145% vs bare peat; warming increased fluxes 111% on bare and 63% with dwarf-shrubs and shifted 14C toward older carbon where shrubs were present.
What is a limit of carbon cycle evidence here?
A mesocosm, a peat profile or a shrub plot does not close the global carbon budget.