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

人为产生的二氧化碳在高纬度地区进入海洋，并从那里扩散到深海内部。由于深海中水深较大的碳酸盐离子饱和度一般会降低，深海珊瑚可能特别容易受到海洋酸化的影响。需要努力确定不断变化的海水化学对这些生态系统的影响，特别是重建这些珊瑚过去经历的pH值变化可能有助于实施深海珊瑚礁的长期管理计划。该项目将提供新的视角，以了解不断变化的海水碳酸盐化学和人为海洋酸化对深海珊瑚礁的影响。研究人员将校准几种现代和养殖深海珊瑚中的硼同位素和B/Ca古pH值代理。由此产生的替代校准将用于解释有关过去海洋pH值变化的活采集和化石深海珊瑚的硼同位素组成。从北大西洋和南大洋收集的活体珊瑚将提供中等深度人为二氧化碳入侵的超高分辨率时间记录。来自同一地点的放射性测定年代的珊瑚将用于记录最后一次冰消期深海的pH值变化。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值重建。资金支持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.