A Coral Skeleton P/Ca Proxy for Surface Ocean Phosphate: Testing and calibration

直接记录表层海洋过去的营养物质浓度将大大增加我们对海洋环流、气候和海气碳通量之间的联系的了解，以及沿海水域将能够重建上升流和富营养化历史。单个珊瑚群体的碳酸钙骨架可以提供数百年来海洋表面状况的连续记录，包括磷酸盐浓度。为此，罗格斯大学的一名研究人员计划开发、校准和应用一种新的珊瑚替代表层海洋磷酸盐，其基础是来自巴拿马湾珊瑚的有希望的初步数据，该数据表明骨骼P/Ca定量记录了季节性上升流情况下地表水磷酸盐的变化。本项目将侧重于根据现场时间序列地表水化学数据对P/Ca替代指标进行校准，以检验以下假设：(1)最近珊瑚中的骨骼P/Ca定量反映了记录在案的相对较高(巴拿马湾：0.2-0.8M)和较低(埃拉特湾，红海：0.01-0.1M)海水磷酸盐的时间序列变化；(2)P/Ca地表水磷酸盐替代物可应用于Pavona和Porite，群体间和群体内的复制将有助于重建地表水磷酸盐的季节性变化；(3)珊瑚磷以无机和有机物种的组合形式并入，使总P/Ca能够抵抗成岩作用，从而允许P/Ca应用于长岩心和珊瑚化石；以及(4)骨骼磷的有机成分主要是分布在亚微米尺度的生物文石中的磷脂，并为研究并入机制提供了一个窗口。至于更广泛的影响，这位科学家将与罗格斯大学COSEE-MA办公室合作开发珊瑚和古海洋学教材。作为该项目的一部分，一名研究生将得到支持和培训。

A direct record of past nutrient concentrations in the surface ocean would add considerably to our understanding of the links between ocean circulation, climate, and air-sea carbon fluxes, and in coastal waters would allow reconstructions of upwelling and eutrophication histories. The calcium carbonate skeleton of a single colony of coral can provide a continuous record of ocean surface conditions, including phosphate concentrations, over hundreds of years. For this reason, an investigator from Rutgers University plans to develop, calibrate, and apply a new coral proxy for surface ocean phosphate based on promising preliminary data from a Gulf of Panama coral indicating skeletal P/Ca quantitatively record variations in surface water phosphate in a seasonal upwelling regime. This project will focus on calibration of the P/Ca proxy against in situ time-series surface water chemistry data, to test the following hypotheses based on findings from the preliminary data: (1) skeletal P/Ca in recent corals quantitatively reflects documented time-series surface water phosphate variations at relatively high (Panama Bay: 0.2-0.8 M) and low (Gulf of Eilat, Red Sea: 0.01-0.1M) seawater phosphate values; (2) the P/Ca surface water phosphate proxy can be applied in Pavona and Porites, and inter- and intra-colony replication would allow reconstruction of seasonal scale surface water phosphate variations; (3) coralline phosphorous is incorporated as a combination of inorganic and organic species that allow total P/Ca to be resistant to diagenetic alteration, permitting application of P/Ca to long cores and fossil corals; and (4) the organic component of skeletal phosphorous largely comprises phospholipids distributed at the sub-micron scale in biogenic aragonite and provide a window into incorporation mechanism. As regards broader impacts, the scientist would collaborate with the COSEE-MA office at Rutgers University to develop coral and paleoceanography teaching materials. One graduate student would be supported and trained as part of this project.