Kamenos Nicholas A, Burdett Heidi L, Aloisio Elena, Findlay Helen S, Martin Sophie, Longbone Charlotte, Dunn Jonathan, Widdicombe Stephen, Calosi Piero
School of Geographical and Earth Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
Glob Chang Biol. 2013 Dec;19(12):3621-8. doi: 10.1111/gcb.12351. Epub 2013 Oct 8.
Marine pCO2 enrichment via ocean acidification (OA), upwelling and release from carbon capture and storage (CCS) facilities is projected to have devastating impacts on marine biomineralisers and the services they provide. However, empirical studies using stable endpoint pCO2 concentrations find species exhibit variable biological and geochemical responses rather than the expected negative patterns. In addition, the carbonate chemistry of many marine systems is now being observed to be more variable than previously thought. To underpin more robust projections of future OA impacts on marine biomineralisers and their role in ecosystem service provision, we investigate coralline algal responses to realistically variable scenarios of marine pCO2 enrichment. Coralline algae are important in ecosystem function; providing habitats and nursery areas, hosting high biodiversity, stabilizing reef structures and contributing to the carbon cycle. Red coralline marine algae were exposed for 80 days to one of three pH treatments: (i) current pH (control); (ii) low pH (7.7) representing OA change; and (iii) an abrupt drop to low pH (7.7) representing the higher rates of pH change observed at natural vent systems, in areas of upwelling and during CCS releases. We demonstrate that red coralline algae respond differently to the rate and the magnitude of pH change induced by pCO2 enrichment. At low pH, coralline algae survived by increasing their calcification rates. However, when the change to low pH occurred at a fast rate we detected, using Raman spectroscopy, weaknesses in the calcite skeleton, with evidence of dissolution and molecular positional disorder. This suggests that, while coralline algae will continue to calcify, they may be structurally weakened, putting at risk the ecosystem services they provide. Notwithstanding evolutionary adaptation, the ability of coralline algae to cope with OA may thus be determined primarily by the rate, rather than magnitude, at which pCO2 enrichment occurs.
通过海洋酸化（OA）、上升流以及碳捕获与封存（CCS）设施释放来增加海洋二氧化碳分压（pCO₂），预计会对海洋生物矿化者及其提供的服务产生毁灭性影响。然而，使用稳定的终点pCO₂浓度进行的实证研究发现，物种表现出可变的生物学和地球化学响应，而非预期的负面模式。此外，现在观察到许多海洋系统的碳酸盐化学变化比以前认为的更大。为了更可靠地预测未来海洋酸化对海洋生物矿化者的影响及其在生态系统服务提供中的作用，我们研究了珊瑚藻对实际可变的海洋pCO₂富集情景的响应。珊瑚藻在生态系统功能中很重要；提供栖息地和育苗区，拥有高生物多样性，稳定珊瑚礁结构并促进碳循环。红色珊瑚藻暴露于三种pH处理之一80天：（i）当前pH（对照）；（ii）代表海洋酸化变化的低pH（7.7）；（iii）突然降至低pH（7.7），代表在自然通风系统、上升流区域和CCS释放期间观察到的更高pH变化速率。我们证明，红色珊瑚藻对pCO₂富集引起的pH变化速率和幅度有不同的反应。在低pH条件下，珊瑚藻通过提高钙化速率得以存活。然而，当快速转变为低pH时，我们使用拉曼光谱检测到方解石骨架存在弱点，有溶解和分子位置无序的迹象。这表明，虽然珊瑚藻将继续钙化，但它们的结构可能会变弱，从而使其提供的生态系统服务面临风险。尽管存在进化适应，珊瑚藻应对海洋酸化的能力可能主要取决于pCO₂富集发生的速率，而非幅度。
