Ecophysiology matters: linking inorganic carbon acquisition to ecological preference in four species of microalgae (Chlorophyceae).
The effect of CO2supply is likely to play an important role in algal ecology. Since inorganic carbon (Ci) acquisition strategies are very diverse among microalgae and Ciavailability varies greatly within and among habitats, we hypothesized that Ciacquisition depends on the pH of their preferred natural environment (adaptation) and that the efficiency of Ciuptake is affected by CO2availability (acclimation). To test this, four species of green algae originating from different habitats were studied. The pH-drift and Ciuptake kinetic experiments were used to characterize Ciacquisition strategies and their ability to acclimate to high and low CO2conditions and high and low pH was evaluated. Results from pH drift experiments revealed that the acidophile and acidotolerant Chlamydomonas species were mainly restricted to CO2, whereas the two neutrophiles were efficient bicarbonate users. CO2compensation points in low CO2-acclimated cultures ranged between 0.6 and 1.4 μM CO2and acclimation to different culture pH and CO2conditions suggested that CO2concentrating mechanisms were present in most species. High CO2acclimated cultures adapted rapidly to low CO2condition during pH-drifts. Ciuptake kinetics at different pH values showed that the affinity for Ciwas largely influenced by external pH, being highest under conditions where CO2dominated the Cipool. In conclusion, Ciacquisition was highly variable among four species of green algae and linked to growth pH preference, suggesting that there is a connection between Ciacquisition and ecological distribution.
Universität Potsdam, Am Neuen Palais 10, 14469, Potsdam, Germany.
Sabrina C
SC
Lachmann
Lake Ecosystems Group, Centre for Ecology & Hydrology, Lancaster Environment Centre, Library Avenue, Lancaster, LA1 4AP, UK.
Stephen C
SC
Maberly
Universität Potsdam, Am Neuen Palais 10, 14469, Potsdam, Germany.
Elly
E
Spijkerman
D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism*; D002696:Chlamydomonas / Q000502:physiology*; D017753:Ecosystem; D006863:Hydrogen-Ion Concentration; D058086:Microalgae / Q000502:physiology*; D044444:Scenedesmus / Q000502:physiology*
D002245:Carbon Dioxide; D002244:Carbon

CCM
; 
Chlamydomonas
; 
Chlorella
; 
Scenedesmus
; CO2 supply; acidophile; carbon acquisition; extremophile; inorganic carbon uptake kinetics; pH-drift