Concept · environmental-science
Ocean acidification
6 studies
Ocean acidification is the drop in seawater pH and carbonate saturation as CO2 dissolves, tested on calcifiers, reefs or coastal chemistry.
It is the marine half of the carbon problem undergraduates meet in environmental science.
Studies
6
Findings
5
7 supporting · 0 challenging · 0 qualifying citations
Open tensions
1
Currently
What we know
- This library holds 6 empirical papers on ocean acidification with measured outcomes rather than reviews.
- After 6 days at pH ~7.7 and 32°C, Galaxea and Acropora RNA-based symbionts shifted and virulence/stress genes rose, changes that often persisted 9 days after stressors ended.
- A 0.2-unit drop in seawater pH over 100 days thins calcareous tube worms and algae while sponges and some sea squirts increase.
- Six weeks of ocean acidification on crustose coralline algae halved Acropora settlement, but larvae still settled on ambient-conditioned CCA even at low pH.
- Selectively bred Saccostrea glomerata keep more ordered calcite and can use different DIC pathways than wild-type oysters in acidified Australian estuaries.
Largest unresolved question
Lab pH treatments and coastal variability are not the same as open-ocean century-scale change.
Common misconceptions
Ocean acidification dissolves every shell equally.
Sensitivity depends on taxon, life stage and the rate of pH change.
Related
Claim ledger
What the evidence shows
Drawn from 6 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 6 empirical papers on ocean acidification with measured outcomes rather than reviews.
- OA and heat push coral microbes toward pathogens
- Lower pH kills spirorbids but favors sponges
- Acidified algae, not larvae, block coral settlement
Study Role Design N Population Outcome OA and heat push coral microbes toward pathogens Supports Animal / in-vitroFactorial aquarium acidification and heat stress on Galaxea and Acropora with RNA-based symbiont profiling N=51 · 51 16S libraries; replicate fragments n=10 per experimental tank condition South China Sea Galaxea fascicularis and Acropora valida coral fragments Active prokaryotic symbiont communities and stress/virulence gene expression under OA and warming Lower pH kills spirorbids but favors sponges Supports Animal / in-vitro100-day flow-through aquarium experiment comparing biofouling at pH 7.9 vs 7.7 N=50 · Spirorbid counts analysed with n=50 quadrats/surfaces; algal scores n=11 Ria Formosa biofouling communities on pipes, HDPE, limestone, and tank walls Live spirorbid density, mortality, and shifts toward sponges/ascidians under acidification Acidified algae, not larvae, block coral settlement Supports Animal / in-vitroCCA pretreated 42 days at reduced pH, then offered to Acropora larvae versus ambient-conditioned CCA and extracts N=6 · n = 6 containers per treatment; 31–39 larvae in acute OA assays Crustose coralline algae and Acropora coral larvae Ocean acidification on CCA halved coral settlement, but larvae still settled on ambient-conditioned CCA even at low pH After 6 days at pH ~7.7 and 32°C, Galaxea and Acropora RNA-based symbionts shifted and virulence/stress genes rose, changes that often persisted 9 days after stressors ended.
A 0.2-unit drop in seawater pH over 100 days thins calcareous tube worms and algae while sponges and some sea squirts increase.
Six weeks of ocean acidification on crustose coralline algae halved Acropora settlement, but larvae still settled on ambient-conditioned CCA even at low pH.
Selectively bred Saccostrea glomerata keep more ordered calcite and can use different DIC pathways than wild-type oysters in acidified Australian estuaries.
Debates
Tensions and limits
Some items are genuine disagreements on the same question. Others mark different assays, populations, or outcomes.
Lab pH treatments and coastal variability are not the same as open-ocean century-scale change.
Lab pH treatments and coastal variability are not the same as open-ocean century-scale change.
Study Role Design N Population Outcome OA and heat push coral microbes toward pathogens Supports Animal / in-vitroFactorial aquarium acidification and heat stress on Galaxea and Acropora with RNA-based symbiont profiling N=51 · 51 16S libraries; replicate fragments n=10 per experimental tank condition South China Sea Galaxea fascicularis and Acropora valida coral fragments Active prokaryotic symbiont communities and stress/virulence gene expression under OA and warming Lower pH kills spirorbids but favors sponges Supports Animal / in-vitro100-day flow-through aquarium experiment comparing biofouling at pH 7.9 vs 7.7 N=50 · Spirorbid counts analysed with n=50 quadrats/surfaces; algal scores n=11 Ria Formosa biofouling communities on pipes, HDPE, limestone, and tank walls Live spirorbid density, mortality, and shifts toward sponges/ascidians under acidification
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
Ocean acidification
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
6 studies in this library bear on Ocean acidification, ordered by citations.
- Acidified algae, not larvae, block coral settlement
Six weeks of ocean acidification on crustose coralline algae halved Acropora settlement, but larvae still settled on ambient-conditioned CCA even at low pH.
- Fast pH drops damage coralline algae more than slow OA
Red coralline algae coped with a gradual drop to pH 7.7 but showed more skeletal dissolution when pH fell abruptly.
- Warming and acidification squeeze coral habitat
Modeled coral-reef suitability falls about 27–30% in shallow water by 2070, worst in the Western Pacific Warm Pool.
- Lower pH kills spirorbids but favors sponges
A 0.2-unit drop in seawater pH over 100 days thins calcareous tube worms and algae while sponges and some sea squirts increase.
- Bred oysters switch shell carbon under acidification
Selectively bred Saccostrea glomerata keep more ordered calcite and can use different DIC pathways than wild-type oysters in acidified Australian estuaries.
- OA and heat push coral microbes toward pathogens
After 6 days at pH ~7.7 and 32°C, Galaxea and Acropora RNA-based symbionts shifted and virulence/stress genes rose, changes that often persisted 9 days after stressors ended.
Compare studies
Select 2–10 studies. Design and N are labels, not a ranking.
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Questions
What is still open
Lab pH treatments and coastal variability are not the same as open-ocean century-scale change.
Ask PaperFren about Ocean acidification
Study this conceptflashcards and short-answer questions
What does ocean acidification mean in this library?
Ocean acidification is the drop in seawater pH and carbonate saturation as CO2 dissolves, tested on calcifiers, reefs or coastal chemistry.
Name one empirical finding from the ocean acidification papers.
After 6 days at pH ~7.7 and 32°C, Galaxea and Acropora RNA-based symbionts shifted and virulence/stress genes rose, changes that often persisted 9 days after stressors ended.
What is a limit of ocean acidification evidence here?
Lab pH treatments and coastal variability are not the same as open-ocean century-scale change.