Manipulation of Seawater Carbonate Chemistry

Abstract

Different culture methods to grow microalgae could lead to different physical (light) and chemical environments in culture vessels. Photosynthetic carbon sequestration by the algae in light and their respiratory CO₂ release in darkness, can affect stability of carbonate systems (pH, various forms of inorganic carbon, total alkalinity) in culture systems. Usually, pH could increase during light period with active photosynthesis, and decrease during dark period. Such changes in pH and associated carbonate chemistry depend on culture methods and cell biomass or densities of microalgae in water body. The greater the amount of carbon fixation in the water, the greater the changes of the carbonate system. In experiments on the influence of other environmental factors on algae, controlling pH and other carbonate system parameters within known stable ranges is one of the keys to obtain reliable data. This section introduces the seawater carbonate system, compares the existing several kinds of carbonate system control methods, and provides basic suggestions for ocean acidification simulation experiments on marine organisms.

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