Ocean Acidification - Category 1: Calibration and application of the boron isotope seawater-pH indicator in deep-water corals

人为的二氧化碳从高纬度地区进入海洋，从那里扩散到深海内部。由于深海中较大水深处的碳酸盐离子饱和度通常会降低，因此深海珊瑚可能特别容易受到海洋酸化的影响。需要努力确定海水化学变化对这些生态系统的影响，特别是这些珊瑚所经历的过去ph变化的重建可能有助于实施深海珊瑚礁的长期管理计划。该项目将为研究海水碳酸盐化学变化和人为海洋酸化对深海珊瑚礁的影响提供新的见解。研究人员将在几种现代和人工养殖的深海珊瑚中校准硼同位素和B/Ca古ph值。由此产生的代理校准将用于解释收集的活珊瑚和化石深海珊瑚的硼同位素组成与过去海洋pH变化的关系。从北大西洋和南大洋收集的活珊瑚将提供中等深度人为CO2入侵的超高分辨率时间记录。来自同一地点的辐射测定年代的珊瑚将被用来记录上次冰川消退期间深海pH值的变化。将古ph值与已经确定的珊瑚物种组成变化进行比较，将有助于解释珊瑚对海洋酸化的敏感性。该项目还将通过交叉校准硼同位素分析的主要技术来改善古ph重建。资助一名年轻女研究员和一名女研究生，并为本科生参与研究提供机会。

Anthropogenic CO2 enters the ocean in the high latitudes, from where it spreads into the deep ocean interior. Because carbonate ion saturation at greater water depth is generally reduced in the deep ocean, deep-sea corals may be particularly vulnerable to ocean acidification. Efforts are needed to determine the effects of changing seawater chemistry on these ecosystems, and in particular reconstructions of past pH-variations experienced by these corals may help to implement long-term management plans for deep-sea coral reefs. This project will provide new insight into the effect of changing seawater carbonate chemistry and anthropogenic ocean acidification on deep-sea coral reefs. The researchers will calibrate the boron isotope and B/Ca paleo-pH proxies in several species of modern and cultured deep-sea corals. The resulting proxy calibrations will be used to interpret the boron isotope composition of live collected and fossil deep-sea corals with regard to past ocean pH changes. Live collected corals from the North Atlantic and Southern Ocean will provide ultra-high resolution temporal records of anthropogenic CO2 invasion at intermediate depths. Radiometrically dated corals from the same locations will be used to document pH changes in the deep ocean over the last deglaciation. Comparison of paleo-pH with already established changes in coral species composition will allow interpretation of coral sensitivity to ocean acidification. The project will also improve paleo-pH reconstructions by cross- calibrating the principal techniques of boron isotope analysis. Funding supports a young female researcher and a female graduate student, and provides opportunities for undergraduate involvement in research.