Seawater carbonate chemistry and blood and endolymph acid-base parameters in control and OA-exposed rockfish

• Main Authors: Kwan, Garfield Tsz, Tresguerres, Martin
• Format: Dataset
• Language: English
• Published: PANGAEA 2022
• Subjects: Acid-base regulation; Alkalinity; total; standard error; Animalia; Aragonite saturation state; Bicarbonate; Bicarbonate ion; Bottles or small containers/Aquaria (<20 L); Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; partial pressure; Chordata; Coast and continental shelf; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Hydrogen ion concentration; Laboratory experiment; Nekton; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.945127; https://doi.org/10.1594/PANGAEA.945127

Over a decade ago, ocean acidification (OA) exposure was reported to induce otolith overgrowth in teleost fish. This phenomenon was subsequently confirmed in multiple species; however, the underlying physiological causes remain unknown. Here, we report that splitnose rockfish (Sebastes diploproa) exposed to 1600 μatm pCO2 (pH 7.5) were able to fully regulated the pH of both blood and endolymph (the fluid that surrounds the otolith within the inner ear). However, while blood was regulated around pH 7.80, the endolymph was regulated around pH 8.30. These different pH setpoints result in increased pCO2 diffusion into the endolymph, which in turn leads to proportional increases in endolymph [HCO3−] and [CO32−]. Endolymph pH regulation despite the increased pCO2 suggests enhanced H+ removal. However, a lack of differences in inner ear bulk and cell-specific Na+/K+-ATPase and vacuolar type H+-ATPase protein abundance localization pointed out to activation of preexisting ATPases, non-bicarbonate pH buffering, or both, as the mechanism for endolymph pH-regulation. These results provide the first direct evidence showcasing the acid-base chemistry of the endolymph of OA-exposed fish favors otolith overgrowth, and suggests that this phenomenon will be more pronounced in species that count with more robust blood and endolymph pH regulatory mechanisms.