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.
Source
Selectively bred oysters can alter their biomineralization pathways, promoting resilience to environmental acidification
What they did
Families bred for QX resistance or fast growth plus wild-type oysters were sampled from control (~pH 8.1–8.2) and acidified (~pH 7.4–7.5) leases; shells were mapped by EBSD and δ13C was measured in seawater, shell, tissue, and extrapallial fluid.
What they found
Acidified seawater was isotopically lighter. Wild-type shells showed more crystallographic disorder. Under acidification shell δ13C went negative, consistent with a switch from HCO3− toward CO32− as the carbon source; selected families already used the CO32−-like signature at control sites.
The limits
What it doesn't show
Small n (12 oysters, 3 per SEM/isotope analysis) and covarying salinity, temperature, and food mean acidification is not isolated; commercial breeding is not a reef-restoration trial.
Key terms
- Coastal acidification
- Low pH in estuaries driven by land runoff and acid sulfate soils, not only atmospheric CO2.
- δ13C
- Carbon-isotope ratio used to infer whether shell carbon comes from HCO3− or CO32− pools.
- EBSD
- Electron backscatter diffraction mapping of calcite crystal orientation.
- Saccostrea glomerata
- Sydney rock oyster farmed in NSW estuaries.
- Extrapallial fluid
- Fluid between mantle and shell where calcification occurs.
Flashcards
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Quiz yourself
Acidified lease pH was about:
Common questions
What pH did acidified leases reach?
About pH 7.4–7.5 versus control 8.1–8.2.
Which shells were more disordered?
Wild-type (F31) calcite vs selected F15/F30.
What happens to shell δ13C under acidification?
It becomes significantly lighter (negative).
Why does that matter?
It implies a shift in inorganic carbon source used for biomineralization.
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