Bivalve shell formation in a naturally CO2-enriched habitat: Unraveling the resilience mechanisms from elemental signatures. (July 2018)

• Record Type: Journal Article
• Authors: Zhao, Liqiang; Milano, Stefania; Walliser, Eric O.; Schöne, Bernd R.
• Is Part Of: Chemosphere. Volume 203(2018)
• Page Start: 132
• Page End: 138
• Publication Date: 2018-07
• Subjects: Ocean acidification -- Shell growth rate -- Geochemical tracers -- Acclimation and adaption -- Marine bivalve mollusks; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2018.03.180
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Marine bivalves inhabiting naturally p CO2 -enriched habitats can likely tolerate high levels of acidification. Consequently, elucidating the mechanisms behind such resilience can help to predict the fate of this economically and ecologically important group under near-future scenarios of CO2 -driven ocean acidification. Here, we assess the effects of four environmentally realistic p CO2 levels (900, 1500, 2900 and 6600 μatm) on the shell production rate of Mya arenaria juveniles originating from a periodically p CO2 -enriched habitat (Kiel Fjord, Western Baltic Sea). We find a significant decline in the rate of shell growth as p CO2 increases, but also observe unchanged shell formation rates at moderate p CO2 levels of 1500 and 2900 μatm, the latter illustrating the capacity of the juveniles to partially mitigate the impact of high p CO2 . Using recently developed geochemical tracers we show that M. arenaria exposed to a natural p CO2 gradient from 900 to 2900 μatm can likely concentrate HCO3 − in the calcifying fluid through the exchange of HCO3 − /Cl − and simultaneously maintain the pH homeostasis through active removal of protons, thereby being able to sustain the rate of shell formation to a certain extent. However, with increasing p CO2 beyond natural maximum the bivalves may have limited capacity to compensate for changes in the calcifying fluid chemistry, showing significant shell growth reduction. Findings of the present study may pave the way for elucidating the underlying mechanisms by which marine bivalves acclimate and adapt to high seawater p CO2 . Highlights: Mya arenaria juveniles from Kiel Fjord can partially alleviate the impact of high p CO2 . Changes in the calcifying fluid chemistry can be inferred from shell elemental signatures. Cl/Cashell reflects the import of HCO3 − in the calcifying fluid. U/Cashell indicates the pH in the calcifying fluid. Our work provides new evidence of how marine bivalves respond to high p CO2 .