Ecological implications of microalgal and cyanobacterial CO2 concentrating mechanisms, and their regulation

The capacity of algae to express CO2 concentrating mechanisms (CCMs) is regulated by environmental factors. Some of these factors, especially photon flux, can influence the instantaneous activity of a CCM without necessarily affecting gene expression or the capacity of the cell to transport inorganic carbon. Other environmental parameters, especially those causing changes in the availability of CO2 dissolved in the surrounding medium, act at a transcriptional level. In this review, the complex interactions between environmental factors in controlling CCM activity will be discussed, as will the ecological consequences of CCMs as they relate to the growth and ecological performance of algal cells in nature. We also consider the consequences of global climate change for the performance of algae with and without CCMs.