Changes in pH and dissolved inorganic carbon in water affect the growth, saxitoxins production and toxicity of the cyanobacterium Raphidiopsis raciborskii ITEP-A1

•Responses of R. raciborskii to different pH/CO2 scenarios were tested;.•Bicarbonate availability governed growth and saxitoxin production in the cyanobacterium;.•R. raciborskii ITEP-A1 is a bicarbonate-user (potentially expresses the BicA transporter);.•Dissolved inorganic carbon and pH influenced saxitoxins production and toxicity in R. raciborskii ITEP-A1.