Turnover rates of photosynthesis determined by fluorescence kinetic analysis.

Maximum photosynthesis turnover rates vary from 80 to 800 s^-1 across different marine environments, reflecting temperature and nutrient influences on phytoplankton.

• Why it matters: Understanding these rates is crucial because they set the upper limit on global primary production, yet current estimation methods are slow and uncertain, hindering accurate ecosystem modeling.
• What they did: A new fluorescence kinetic analysis method was developed, using instantaneous measurements under saturating light to determine maximum turnover rates in model algae and diatoms across diverse conditions.
• The result: The study found a strong linear correlation between turnover rates and cell growth, enabling a practical tool to assess nutrient effects on phytoplankton productivity and improve oceanic biogeochemical models.