Gene expression in Balanus improvisus
Salinity- and CO2-induced expression changes were studied in the eurohaline barnacle Balanus improvisus (= Amphibalanus improvisus).  Cyprid larvae were subjected to two salinities (33 PSU or 6 PSU) combined with two pCO2 levels (380 ppm or 970 ppm). Salinity levels were based on the salinity that the barnacles were collected from and long-termed reared in (30-33 PSU), as well as the salinity of the central parts of the Baltic Sea (6 PSU) (also a habitat for B. improvisus). pCO2 levels were based on current ambient CO2 concentrations (380 ppm) as well as predictions by the Intergovernmental Panel on Climate Change (IPCC) climate models for year 2100 (970 ppm). The low salinity treatment was obtained by mixing 33 PSU of sterile filtered seawater with water filtered by reverse osmosis. The control CO2 treatment was determined by bubbling ambient air (with approx. 380ppm pCO2) in 5 L bottles of seawater of both 33 and 6 PSU until saturation was reached and pH was stabilized. The same procedure was performed for the high CO2 concentration using a gas cylinder with pre-mixed air with pCO2 levels of 970 ppm (AGA). The combination of the two different salinities and two saturating pCO2 levels resulted in four different pH levels. pH computers (Aqua Medic pH computer, Aqua Medic AB GmbH) were used to control the mixture of air and CO2 coming into the system to keep the pH stable at these four levels throughout the experiment. Measured pH: Norm CO2/High salt (ctrl) pH=8.14; Norm CO2/Low salt pH=7.65; High CO2/High salt pH=7.80; High CO2/Low salt pH=7.37.  Additional and associated data can be found at 10.17044/scilifelab.25472605