Tolerance of juvenile Mytilus galloprovincialis to experimental seawater acidification

Abstract

Coastal ocean acidification is expected to interfere with the physiology of marine bivalves. In this work, the effects of acidification on the physiology of juvenile mussels Mytilus galloprovincialis were tested by means of controlled CO 2 perturbation experiments. The carbonate chemistry of natural (control) seawater was manipulated by injecting CO 2 to attain 2 reduced pH levels: −0.3 and −0.6 pH units as compared with the control seawater. After 78 d of exposure, we found that the absorption efficiency and ammonium excretion rate of juveniles were inversely related to pH. Significant differences among treatments were not observed in clearance, ingestion and respiration rates. Coherently, the maximal scope for growth and tissue dry weight were observed in mussels exposed to the pH reduction ΔpH = −0.6, suggesting that M. galloprovincialis could be tolerant to CO 2 acidification, at least in the highly alkaline coastal waters of Ria Formosa (SW Portugal).KEY WORDS: Ocean acidification · Blue mussels · Feeding behaviour · Physiological energetics · Absorption bivalves · Metabolism Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 454: [65][66][67][68][69][70][71][72][73][74] 2012 lidis et al. 2005), others seem to be surprisingly tolerant (e.g. Gutowska et al. 2008). Naturally acidified habitats allow to investigate organisms and communities under high pCO 2 conditions in general (e.g. Hall-Spencer et al. 2008, Fabricius et al. 2011) and mussels in particular , RodolfoMetalpa et al. 2011. Multi-generation experiments can also contribute important evidence about the sensitivity and adaptation potential of a given species. Considering the scarcity of that type of study, an alternative approach is to look at indicators for animal performance during long-term CO 2 perturbation experiments (Melzner et al 2009).Bivalves dominate the macrofauna of many estuaries and coastal embayments. Understanding their physiological behaviour is crucial for determining their productivity and energy flows. Changes in environmental variables can affect physiological processes in bivalves, modifying their influence on the ecosystem. These effects need to be evaluated in an integrated way, given the important role these organisms play in terms of ecological structure and their value as economic resources for fisheries and aquaculture in many coastal areas. The potential of significant ecological and economic consequences arising from the effects of ocean acidification on bivalves and the need for further research on commercially important species has been explicitly recognized (Kleypas et al. 2006, Fabry et al. 2008, Cooley & Doney 2009.Scientific research on the effects of seawater acidification on bivalves has been increasing rapidly in recent years. Most previous studies have focused on growth and calcification of the shell (Berge et al. 2006, Gazeau et al. 2007, Miller et al. 2009, Gazeau et al. 2010, Thomsen & Melzner 2010, feeding behaviour, reproduction and metabolism (Mi...

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

“…For instance, Thomsen & Melzner (2010) reported that shell growth of Mytilus edulis from the Baltic Sea decreased linearly with increasing pCO 2 , while NH 4 + excretion increased linearly. 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.…”

Impact of ocean acidification on thermal tolerance and acid–base regulation of Mytilus edulis (L.) from the North Sea

“…Over a similar time period moderate hypercapnia of~2000 μatm caused a significant reduction of oxygen consumption, clearance and ingestion rates in clams Ruditapes decussatus (Fernández-Reiriz et al, 2011). Further studies found no effect of CO 2 levels projected by 2100 (≤2000 μatm) on oxygen consumption rates of bivalves (Lannig et al, 2010;Fernández-Reiriz et al, 2012;Liu and He, 2012;Schalkhausser et al, 2012). In M. edulis from the Baltic (Kiel Fjord) no reduction in oxygen consumption was found even at 2500 μatm .…”

Impacts of ocean acidification on marine shelled molluscs

“…Like a number of shelled mollusc species, however, compensation of pHe occurred from the accumulation of HCO 3 -, derived primarily from shell dissolution, as evidenced by an increase in extracellular [Ca 2? ]. In contrast, in the mussel M. galloprovincialis, exposure to moderately elevated CO 2 (-0.3-unit pH reduction) had no effect on the SMR, somatic growth, clearance, ingestion and excretion rates (Fernandez-Reiriz et al 2012). While other processes such as shell growth, acid-base status and immune response were not investigated, this species seems somewhat resilient to moderate elevations in pCO 2 (but see Michaelidis et al 2005 earlier in this section for lower pH conditions).…”

“…In the limpet Patella vulgata (Marchant et al 2010), mussels Perna viridis (Liu and He 2012) and M. galloprovincialis (Fernandez-Reiriz et al 2012) and oyster Pinctada fucata (Liu and He 2012), there was no observable change in SMR during exposure to elevated CO 2 (see Fig. 4).…”