THE EFFECT OF pH ON THE DIVISION RATE OF THE COCCOLITHOPHORID CRICOSPHAERA ELONGATA(1)

Area of Science:

• Marine biology
• Microbiology
• Biochemistry

Background:

• Cricosphaera elongata is a marine coccolithophorid crucial to oceanic carbon cycles.
• Understanding its cell division is key to predicting its response to environmental changes.
• Coccolith formation is influenced by seawater chemistry, including pH and carbonate availability.

Purpose of the Study:

• To determine the optimal pH for Cricosphaera elongata cell division.
• To investigate the effect of varying carbon dioxide (CO2) partial pressures on division rate.
• To assess the impact of bicarbonate and carbonate concentrations on cell division.

Main Methods:

• Culturing Cricosphaera elongata in a controlled laboratory setting.
• Buffering the culture medium using the CO2-bicarbonate-carbonate system.
• Measuring cell division rates across a range of pH values and chemical conditions.

Main Results:

• The optimal pH for Cricosphaera elongata cell division was identified as 7.8.
• Division rates remained unaffected by changes in CO2 partial pressure (0.03% to 5%).
• Bicarbonate (0.1-6.0 mM) and carbonate (0.007-0.1 mM) concentrations did not influence division rates between pH 6.4 and 7.8.

Conclusions:

• Cricosphaera elongata exhibits a specific pH optimum for cell division, around 7.8.
• The organism's division rate is robust to variations in CO2 partial pressure and common ranges of bicarbonate and carbonate concentrations.
• Environmental factors like pH significantly influence C. elongata motility and morphology, affecting its ecological behavior.