Impacts of CO2-induced seawater acidification on coastal Mediterranean bivalves and interactions with other climatic stressors

Physiological energetics of the thick shell mussel Mytilus coruscus exposed to seawater acidification and thermal stress

“…Liu and He (2012) reported that the excretion rates were significantly lower at pH 7.4 than pH 7.8 for three bivalve species. These results did not agree with some authors who explained the increase in ammonia excretion by the animals exposed to high pCO 2 levels as a result of the enhancement of protein metabolism which contributed to intracellular pH regulation (Michaelidis et al, 2005;Fernández-Reiriz et al, 2005, 2011Thomsen and Melzner, 2010;Range et al, 2014). In bivalves, most ammonia excreted is a product of the catabolism of amino acids from the metabolic reserve as from diet (Saucedo et al, 2004;Mao et al, 2006).…”

“…Michaelidis et al (2005), working on the mussel M. galloprovincialis, suggested that a reduction in RR is associated with seawater acidification. Reduced metabolic rates were also found in the clam R. decussates (Fernández-Reiriz et al, 2011;Range et al, 2014) and the mussel M. chilensis (Navarro et al, 2013) under reduced pH. Liu and He (2012) found that pH 7.4 significantly reduced the RR of C. nobilis.…”

“…Thus, medium and long-term experiments avoid misinterpretations due to the initial acclimatization ability of a species to high levels of seawater acidification. The effects of seawater acidification on CR were also studied on three coastal bivalve species in different regions: the mussel M. galloprovincialis and the clams Chamelea gallina and R. decussates (Range et al, 2014). Reduced clearances were observed for R. decussatus under reduced pH.…”

Comparison of the alkalinity and calcium anomaly techniques to estimate rates of net calcification

“…The same observations were made by Fernandez-Reiriz et al (2012) and for M. galloprovincialis from the European Atlantic coast. In contrast, Range et al (2014) showed that while shell thickness and integrity of M. galloprovincialis from the Adriatic Sea decreased at low pH, suggesting lower calcification rates, excretion did not appear to be as sensitive. Since there is no clear consensus on the effect of ocean acidification on N excretion of shelled mollusks (Gazeau et al 2013) and in order to avoid any misinterpretations, we strongly recommend systematically measuring changes in NH 4 + while estimating calcification rates based on A T variations.…”

CO2-induced pH reduction increases physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus

“…Gran titration was applied to measure total alkalinity (TA) with a total alkalinity titrator system68. The pH and TA were used to calculate other carbonate system parameters, i.e., partial pressure of CO 2 (pCO 2 ) and dissolved inorganic carbon (DIC), and the saturation state of omega calcite and aragonite using CO 2 SYS software as described previously37.…”