Scales of pH variability on Pacific coral reefs reconstructed from skeletal boron and boron isotopes

珊瑚礁生态系统的活力下降常常被认为是与海洋逐渐吸收化石燃料二氧化碳和随之而来的海洋酸化有关的最突出的代价之一。然而，尽管突出的问题，目前尚不清楚是否以及如何区域海洋学引起的pH值变化实际上是在珊瑚钙化的网站上表现出来。这种不确定性要求对不同的珊瑚礁系统进行全面监测。 作为对现场监测装置的一种补充办法，斯克里普斯海洋学研究所的一个研究小组将利用世纪后期太平洋/大气变化的已知变化，作为一种回顾性监测系统。实际上，从这个有针对性的珊瑚样本网络的测量系统将提供一个直接的比较，以事后预测的预期的pH值变化所迫使的海洋变化。该项目的这些结果将允许直接评估在多大程度上大规模的珊瑚在各种海洋环境中实际上是敏感的区域pH值的历史变化。该项目将作为一个学生的博士研究谁扩大了严重代表性不足的群体的参与。该项目还将通过SIO Birch Aquarium展览作为公共宣传平台。研究小组将测量现有珊瑚岩心中的珊瑚骨骼化学，这些岩心来自代表历史上太平洋海盆变化的非常不同的地理极点的地点。具体来说，他们将应用硼同位素替代pH值，结合一套可能对海水碳化学扰动敏感的其他骨骼示踪剂，以生成季节性分辨的环境变化记录。其中两个研究地点，帕尔米拉和莫雷阿，具有持续多年的原位pH传感器安装。因此，研究小组将收集和分析这些地点最近的珊瑚生长情况，这将为实地校准骨骼代用品提供最佳手段。一般而言，评估钙化地点pH值变化的规模，特别是其与海洋扰动的关系，对于正确预测未来人类活动对珊瑚礁碳化学的影响至关重要。

The decreased vitality of coral reef ecosystems is often cited as one of the most prominent costs associated with the progressive oceanic uptake of fossil fuel carbon dioxide and the consequent ocean acidification. Yet, despite the prominent concerns, it is presently unknown whether and how regional oceanographically-induced pH variability is actually manifested at the site of coral calcification. This uncertainty requires comprehensive monitoring of diverse reef systems. As a complementary approach to in situ monitoring installations, a research team from the Scripps Institution of Oceanography will make use of the known changes in Pacific ocean/atmosphere variability of the late 20th century as a retrospective monitoring system. In effect, the system of measurements from this targeted network of coral samples will provide a direct comparison to hindcast expectations of the pH variability forced by oceanographic change. These results of this project will allow a direct assessment of the extent to which massive corals in various oceanographic settings were actually sensitive to historical changes in regional pH. The project will serve as the doctoral research of a student who broadens participation of severely underrepresented groups. The project will also be used as a platform for public outreach through SIO Birch Aquarium exhibits. The research team will measure coral skeletal chemistry in existing coral cores from locations that represent very different geographic poles of historical Pacific basin-wide changes. Specifically, they will apply the boron isotopic proxy for pH, in conjunction with a suite of other skeletal tracers that might be sensitive to perturbations in seawater carbon chemistry, to generate seasonally-resolved records of environmental changes. Two of the study sites, Palmyra and Moorea, feature on going, multi-year in situ pH sensor installations. Accordingly, the research team will collect and analyze the most recent coral growth at these locations, which will provide the best available means for field calibration of the skeletal proxies. In general, the assessment of the scale of pH variability manifested at the site of calcification--and, especially, its relationship with oceanographic perturbations--is essential for establishing the proper perspective for projections of future anthropogenic effects on reef carbon chemistry.