Dynamic changes in phycosphere carbonate chemistry reveal rapid modulation of carbon uptake in single diatom cells.

ABSTRACT: Diatoms use multiple mechanisms of dissolved inorganic carbon (DIC) uptake to maintain CO₂ supply to RuBisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase), but how these different pathways are coordinated in response to rapid changes in their environment remains unclear. By measuring the dynamic changes in phycosphere carbonate chemistry around single diatom cells, we show that DIC uptake is rapidly modulated. We find that external carbonic anhydrase (eCA) plays a major role in DIC uptake in large centric diatoms at ambient seawater CO₂, but there is a strong switch to direct HCO₃^- uptake under low CO₂. Inhibition of eCA leads to rapid activation of HCO₃^- uptake, which can compensate for the loss of eCA activi

SUBMITTER: Keys M 

PROVIDER: S-EPMC12758531 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature