The proteomic response of larvae of the Sydney rock oyster, Saccostrea glomerata to elevatedpCO₂

Abstract

Acidification of oceans is predicted to fundamentally alter marine ecosystems. It is anticipated that by 2100, the concentration of CO 2 may double preindustrial levels and reach >750ppm, and lead to changes in seawater chemistry including a reduction in pH of 0.4 units (Calderia and Wickett 2003). This change in pH will directly affect marine organisms that construct their shells and skeletons from calcium carbonate (CaCO 3), and will pose significant challenges to aquaculture

The Impact of Ocean Acidification on Reproduction, Early Development and Settlement of Marine Organisms

“…There was also down regulation of biomineralization, skeletogenesis and energy metabolism genes, whilst some acid-base and ion regulation genes were up-regulated in larvae of the sea urchin Lytechinus pictus which were significantly smaller and had more triangular skeletons and shorter arms than controls [80]. In contrast, decreased pH also had no effect on expression of two shell mineralisation genes ap24 or engrailed at any developmental stage in the abalone Haliotis rufescens [74], but up and down regulation of proteins was found in Saccostrea glomerata, although these are yet to be identified [46]. Up and down regulation of genes associated with various pathways during exposure to ocean acidification suggests an organisms effort to compensate for the effects of elevated pCO 2 [81].…”

“…If we are to move forward we need chronic experiments which allow the potential for species to acclimate over long term perturbations a measure of variability in responses of organisms within and between populations and an assessment of adaptive capacity associated environmentally induced plasticity [117] and focus on identifying the underlying mechanisms [43,44,46,77]. Current models remain constrained by acute experiments where in a period of days there is a sudden drop in pH of 0.4 units which does not mimic well the longer time frame over which this will occur (0.0044 pH/yr [15]).…”

“…Current models remain constrained by acute experiments where in a period of days there is a sudden drop in pH of 0.4 units which does not mimic well the longer time frame over which this will occur (0.0044 pH/yr [15]). Negative results from short term studies on larvae make it difficult to extrapolate to long term impacts on marine environments absolutely, especially when these potentially could couple with positive effects on adults (increased production and robustness of propagules, [15]) and greater capacity to acclimate [42,43,46] giving further support for an entire life cycle environmental approach to measuring the impact of ocean acidification. Extrapolation is also difficult because results from the laboratory are not necessarily replicable in the field and caution is needed with translating between these two contexts because of unforeseen consequences [38,118,119].…”

“…Similarly, calcification rate differed between source populations of Mercenaria spp. signifying possible genotypic variation [44], while maternal provisioning may safe guard larvae from a high CO 2 world and lead to differences in evolutionary responses between species including molluscs and echinoderms [46,75].…”

“…Most recently the neutral or negative response of larvae to ocean acidification in marine organisms has been questioned [32] with suggestions that lecithotrophic larvae, produced by approximately 10% of marine benthic invertebrates, may be better competitors and less affected than approximately 60-90% of marine organisms which produce planktotrophic larvae and feed on exogenous sources. It may well be that lower pH impacts planktotrophic larvae by reducing feeding rate or efficiency [43,46].…”