The rhodolith-forming coralline red algal species Lithothamnion glaciale is the key ecosystem engineer of rhodolith beds on the coast of Svalbard. Because it significantly increases local biodiversity in this high-Arctic environment, we investigate the potential impact of changing environmental parameters on its calcite skeleton. Using energy-dispersive X-ray spectroscopy and environmental data from the Norwegian government’s environmental monitoring, we show that the magnesium concentration within an analysed algal calcite skeleton decreases linearly and significantly over a 40-year time span (R2 = 0.267, pperm < 0.001). Mg/Ca ratios show the most significant correlation with atmospheric CO2 concentrations (R2 = 0.614, p < 0.001), and lower correlations to sea ice cover and seawater temperature. This raises the question of whether the Mg/Ca in the rhodolith skeleton is reflecting an increase in aqueous pCO2 that drives ongoing ocean acidification. Since such a change in geochemistry may alter the stability of the calcite skeleton, our results could imply an impact on the future role of the rhodoliths as ecosystem engineers and consequently on Arctic biodiversity.

中文翻译：

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北极红石的骨骼镁/钙比率是否反映了大气 CO2 浓度？

形成红石的珊瑚红藻物种 Lithothamnion glaciale 是斯瓦尔巴群岛海岸红石床的关键生态系统工程师。因为它在这个高北极环境中显着增加了当地的生物多样性，我们调查了环境参数变化对其方解石骨架的潜在影响。使用能量色散 X 射线光谱和来自挪威政府环境监测的环境数据，我们表明分析的藻类方解石骨架中的镁浓度在 40 年的时间跨度内呈线性显着下降（R2 = 0.267，perm < 0.001） . Mg/Ca 比率显示与大气 CO2 浓度最显着的相关性 (R2 = 0.614, p < 0.001)，与海冰覆盖和海水温度的相关性较低。这就提出了一个问题，即红石骨架中的 Mg/Ca 是否反映了 pCO2 水溶液的增加，从而推动了持续的海洋酸化。由于地球化学的这种变化可能会改变方解石骨架的稳定性，我们的结果可能意味着对红石作为生态系统工程师的未来角色的影响，从而对北极生物多样性产生影响。