Ocean acidification reduces the crystallographic control in juvenile mussel shells

Abstract

Please cite this article as: Fitzer, S.C., Cusack, M., Phoenix, V.R., Kamenos, N.A., Ocean acidification reduces the crystallographic control in juvenile mussel shells, Journal of Structural Biology (2014), doi: http://dx.doi.org/ 10. 1016/j.jsb.2014.08.007 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Keywords: biomineralisation, ocean acidification, temperature, mussels, CO 2 , multiple stressors AbstractGlobal climate change threatens the oceans as anthropogenic carbon dioxide causes ocean acidification and reduced carbonate saturation. Future projections indicate under saturation of aragonite, and potentially calcite, in the oceans by 2100. Calcifying organisms are those most at risk from such ocean acidification, as carbonate is vital in the biomineralisation of their calcium carbonate protective shells. This study highlights the importance of multi-generational studies to investigate how marine organisms can potentially adapt to future projected global climate change. Mytilus edulis is an economically important marine calcifier vulnerable to decreasing carbonate saturation as their shells comprise two calcium carbonate polymorphs: aragonite and calcite. M. edulis specimens were cultured under current and projected pCO 2 (380, 550, 750 and 1000 µatm), following 6 months of experimental culture, adults produced second generation juvenile mussels. Juvenile mussel shells were examined for structural and crystallographic orientation of aragonite and calcite. At 1000 µatm pCO 2 , juvenile mussels spawned and grown under this high pCO 2 do not produce aragonite which is more vulnerable to carbonate undersaturation than calcite. Calcite and aragonite were produced at 380, 550 and 750 µatm pCO 2 .Electron back scatter diffraction analyses reveal less constraint in crystallographic orientation with increased pCO 2 . Shell formation is maintained, although the nacre crystals appear corroded and crystals are not so closely layered together. The differences in ultrastructure and crystallography in shells formed by juveniles spawned from adults in high pCO 2 conditions may prove instrumental in their ability to survive ocean acidification.

Ocean acidification and temperature increase impact mussel shell shape and thickness: problematic for protection?

“…This is reflected in calcite (Ω Ca) and aragonite (Ω Ar) saturation states, which are similar to other ocean acidification studies examining brackish water environments (Thomsen and Melzner 2010) and the natural variability present at the collection site (Fitzer et al. 2014a,b, 2015). Seawater salinity, temperature, and dissolved oxygen (DO) were checked daily and recorded once a week (YSI Pro2030).…”

“…2007) combined with spectrometric analysis using bromocresol indicator (Yao and Byrne 1998) following methods of Fitzer et al. (2014a) and dissolved inorganic carbon (DIC) using an Automated Infra Red Inorganic Carbon Analyzer (AIRICA, Marianda instruments). Certified seawater reference materials for oceanic CO 2 (Batch 137, Scripps Institution of Oceanography, University of California, San Diego) were used as standards to quantify the error of analysis (measured TA μ mol kg −1 , DIC μ mol kg −1 , CRM values TA, and DIC μ mol kg −1 ) (Dickson et al.…”

The effects of environment on <i>Arctica islandica</i> shell formation and architecture

“…So far, variations of the crystallographic properties of bivalve biominerals have been exclusively investigated as a response to hypercapnic (acidified) conditions. Mytilus galloprovincialis and Mytilus edulis showed a significant change in the orientation of the prisms forming shell calcitic layer when subjected to hypercapnia (Hahn et al, 2012;Fitzer et al, 2014a). Altered crystallographic organization may derive from the animal exposure to suboptimal conditions.…”

Marine projections of warming and ocean acidification in the Australasian region

“…Other important calcifying organisms such as benthic forams, may become extinct by the end of this century under high emissions (Uthicke et al, 2013). Other species of calcifying organisms show weakened calcified structures and reduced rates of calcification repair under high emissions (Coleman et al, 2014;Fitzer et al, 2014) potentially making these organisms more vulnerable to other environmental stressors.…”