Fitzer Susan C, Cusack Maggie, Phoenix Vernon R, Kamenos Nicholas A
School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
J Struct Biol. 2014 Oct;188(1):39-45. doi: 10.1016/j.jsb.2014.08.007. Epub 2014 Aug 30.
Global 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 pCO2 (380, 550, 750 and 1000μatm), following 6months of experimental culture, adults produced second generation juvenile mussels. Juvenile mussel shells were examined for structural and crystallographic orientation of aragonite and calcite. At 1000μatm pCO2, juvenile mussels spawned and grown under this high pCO2 do not produce aragonite which is more vulnerable to carbonate under-saturation than calcite. Calcite and aragonite were produced at 380, 550 and 750μatm pCO2. Electron back scatter diffraction analyses reveal less constraint in crystallographic orientation with increased pCO2. 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 pCO2 conditions may prove instrumental in their ability to survive ocean acidification.
全球气候变化威胁着海洋，因为人为排放的二氧化碳导致海洋酸化并降低了碳酸盐饱和度。未来预测表明，到2100年海洋中的文石，甚至可能还有方解石，将处于不饱和状态。钙化生物是受这种海洋酸化影响最大的生物，因为碳酸盐在它们碳酸钙保护壳的生物矿化过程中至关重要。这项研究强调了多代研究的重要性，以调查海洋生物如何可能适应未来预测的全球气候变化。紫贻贝是一种具有重要经济价值的海洋钙化生物，由于其外壳由两种碳酸钙多晶型物：文石和方解石组成，因此容易受到碳酸盐饱和度下降的影响。将紫贻贝标本在当前和预测的pCO2（380、550、750和1000μatm）条件下培养，经过6个月的实验培养后，成年个体产生了第二代幼体贻贝。对幼体贻贝的外壳进行了文石和方解石的结构和晶体取向检查。在1000μatm pCO2条件下，在这种高pCO2环境中产卵和生长的幼体贻贝不会产生文石，文石比方解石更容易受到碳酸盐不饱和状态的影响。在380、550和750μatm pCO2条件下产生了方解石和文石。电子背散射衍射分析表明，随着pCO2的增加，晶体取向的约束减少。外壳形成得以维持，尽管珍珠层晶体似乎受到腐蚀，并且晶体没有如此紧密地层叠在一起。在高pCO2条件下由成年个体产生的幼体形成的外壳在超微结构和晶体学上的差异，可能对它们在海洋酸化环境中生存的能力起到重要作用。
