Ocean acidificationphysiological response from fish to cell

Resumen

The atmospheric concentrations of CO2 have increased at an unusually rapid rate, from pre-industrial levels of 280 μatm to current levels of 414 μatm. The oceans, one of the largest CO2 reservoirs, continuously absorb the atmospheric CO2, resulting in a decline of ocean pH and a decrease in carbonate saturation state. The study of the physiological effects induced by the predicted rise of seawater pCO2 levels will elucidate the capacity of marine fish to adapt or acclimate to future climate change scenarios. In this context, the marine fish intestine has an important role in the acclimatisation mechanisms to environmental stressors. Therefore, this Ph.D. thesis aimed to provide new insights into the intestinal response to a simulated predicted ocean acidification scenario at the functional and molecular level. Using the European sea bass (Dicentrarchus labrax) as an animal model, the present study’s main focus was on the effects of high pCO2 levels in the intestinal bicarbonate handling cascade. Additionally, the characterization of the basal HCO3- secretion as ion/water transport mechanisms unveiled the region-dependent organization of the fish intestine. The marine fish physiological phenotype under a high pCO2 environment was established by a comprehensive analysis not only at the intestinal level but also at the whole-body level. Moreover, the intestinal transcriptome was analysed to gain insights into the underlying cellular and molecular mechanisms present in the observed phenotype. RNA-Seq analysis identified novel gene markers involved in the intestinal response to high pCO2 levels. Overall, this study provided new insights into marine/euryhaline fish intestinal response, which contributed to a better understanding of the physiological adaptations and the regulatory mechanisms involved.