AB - Vol. 23 No.2 - Feature article

Cells of the marine diatom Skeletonema costatum subjected to acute changes in pH. Photo: Anonymous

Zheng Y, Giordano M, Gao K

 

Photochemical responses of the diatom Skeletonema costatum grown under elevated CO2 concentrations to short-term changes in pH

 

Most studies on ocean acidification have concerned the acclimation of organisms to different pCO2 concentrations. To test whether such acclimation modifies responses to pH, Zheng and co-workers investigated the impact of abrupt changes in pH on cells of the diatom Skeletonema costatum acclimated to 390 and 1000 µatm CO2. They found that cells acclimated to high CO2 levels had a higher photosynthetic efficiency than cells acclimated to low pCO2. An abrupt pH decrease from 8.2 to 7.6 did not affect the photosynthetic quantum yield of cells cultured at high CO2 concentrations, whereas quantum yield decreased dramatically in cells grown at low CO2. Acclimation to high CO2 levels thus mitigates the effects of short-term acidification on the photophysiology of S. costatum.

 

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