Biomineralization in Deep-sea Corals: Empirical Tracer Calibration Coupled to a Mechanistic Model of Skeletal Growth

深海珊瑚的生物矿化：经验示踪剂校准与骨骼生长机制模型相结合

• 批准号: 1737404
• 负责人: Jess Adkins
• 金额: $ 43.67万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1737404&HistoricalAwards=false
• 关键词: Biomineralization; Deep; sea; Corals; Empirical

Our direct record of how the climate has changed is limited to the relatively recent period of time where calibrated instruments (thermometers, hygrometers, wind vanes, etc.) have been deployed. This instrumental record covers the last 100-150 years. If we want to exploit the large changes in past climate to better understand how the system works, we need archives capable of recording 'proxies' of the variables we care about. Far and away the most successful archive of past climate from the oceans comes from the shells of calcium carbonate secreting organisms. Shells from open ocean dwellers like foraminifera and coccoliths make up a large percentage of the seafloor sediments. Archives also include the annually banded skeletons of corals and mollusks. However, all of these incorporate proxies for past climate (Mg/Ca as a thermometer for instance) through the filter of biomineralization. These organisms modify the chemistry of their skeletons in only partially known ways, and these 'vital effects' hinder our ability to decode how climate has changed in the past. This project aims to better understand this biomineralization process through a combination of well-posed observations and a newly successful model of the calcification process. This project will focus on deep-sea corals because these animals live in an environment today that does not change very much. This makes them a good 'lab rat' since we can study a modern organism in the wild and still have controlled experiments. The broader impacts of this project include support for a graduate student to work directly on the research and outreach through public lectures and videos to reach a wide range of audiences.The deep-sea coral D. dianthus has a regular banding pattern and correlated geochemical tracer values that follow the banding. These patterns, and the ubiquity and usefulness of the archive, make this species an ideal target for further tracer development. Growing in near constant conditions, variations in stable isotopes and Me/Ca ratios within this coral's skeleton can only be due to 'vital effects'. This project will develop better thermometers and carbonate system proxies in D. dianthus using a two-pronged approach. The existing modern sample collection contains 41 individuals from a wide range of temperature, carbonate and phosphate concentrations. Bulk measurements of Li, B, Mg, Ca, Sr, Ba, and U using a multi-element ICP-MS method will give the empirical relationship between skeleton and seawater. Microanalysis of individual skeletons using SIMS and NanoSIMS will elucidate the internal structure of the geochemistry and add del11B. A new model of the biomineralization process in the coral's Extracellular Calcifying Fluid shows that it can correctly predict the linear relationship between del18O and del13C seen in D. dianthus and a wide array of marine calcifiers. This project will expand this model to include Me/Ca ratios and to test it against the SIMS and bulk analysis observations. The goal of the project is to create better tracers through improved characterization of the biomineralization process. While the model is already showing its worth, the plan to collect an empirical modern sample calibration dataset ensures that it can also improve modern calibrations.

我们关于气候如何变化的直接记录仅限于相对较近的时期，在该期限中，已经部署了经过校准的仪器（温度计，水计，风叶片等）。 该乐器记录涵盖了过去的100 - 50年。 如果我们想利用过去气候中的巨大变化以更好地了解系统的工作原理，则需要能够记录我们关心的变量的“代理”的档案。 从海洋中，过去气候中最成功的档案库来自碳酸钙分泌生物的壳。 来自开放海洋居民（如有孔虫和可可石）的贝壳占海底沉积物的很大一部分。 档案还包括每年带珊瑚和软体动物的骨架。 但是，所有这些都通过生物矿化过滤器结合了过去气候的代理（例如，作为温度计）。 这些生物只以部分已知的方式改变其骨骼的化学反应，而这些“重要效应”阻碍了我们解释过去气候如何变化的能力。 该项目旨在通过结合良好的观察结果和新成功的钙化过程模型来更好地理解这种生物矿化过程。 该项目将重点放在深海珊瑚上，因为这些动物生活在当今没有太大变化的环境中。 这使它们成为一个很好的“实验室大鼠”，因为我们可以在野外研究现代生物，并且仍然进行了控制的实验。 该项目的更广泛影响包括支持研究生直接通过公共讲座和视频进行研究，以吸引广泛的观众。深海Coral D. Dianthus具有常规的乐队乐队模式，并关联了遵循乐队的地球化学示踪剂。 这些模式以及档案的无处不在和实用性，使该物种成为进一步示踪剂发展的理想目标。 在几乎恒定的条件下生长，该珊瑚骨骼内稳定的同位素和ME/CA比的变化只能是由于“重要效应”。 该项目将使用两管齐下的方法在D. Dianthus中开发更好的温度计和碳酸盐系统代理。 现有的现代样品收集包含来自温度，碳酸盐和磷酸盐浓度的41个个体。 LI，B，MG，CA，SR，BA和U使用多元素ICP-MS方法的批量测量将使骨骼与海水之间的经验关系。 使用SIMS和Nanosims对单个骨骼进行微分析将阐明地球化学的内部结构并添加Del11b。 珊瑚细胞外钙化流体中生物矿化过程的新模型表明，它可以正确预测D. Dianthus和广泛的海洋钙化器中Del18O和Del13c之间的线性关系。 该项目将扩大此模型，以包括ME/CA比率，并根据SIMS和批量分析观察进行测试。 该项目的目的是通过改善生物矿化过程的表征来创建更好的示踪剂。 尽管该模型已经显示出其价值，但收集经验现代样品校准数据集的计划可确保它也可以改善现代校准。

项目成果

Carbonic anhydrase, coral calcification and a new model of stable isotope vital effects

• DOI: 10.1016/j.gca.2018.02.032
• 发表时间: 2018-09-01
• 期刊: GEOCHIMICA ET COSMOCHIMICA ACTA
• 影响因子: 5
• 作者: Chen, Sang;Gagnon, Alexander C.;Adkins, Jess F.
• 通讯作者: Adkins, Jess F.

A Cenozoic record of seawater uranium in fossil corals

珊瑚化石中海水铀的新生代记录

• DOI: 10.1016/j.gca.2019.01.039
• 发表时间: 2019
• 期刊: Geochimica et Cosmochimica Acta
• 影响因子: 5
• 作者: Gothmann, Anne M.;Higgins, John A.;Adkins, Jess F.;Broecker, Wally;Farley, Kenneth A.;McKeon, Ryan;Stolarski, Jarosław;Planavsky, Noah;Wang, Xiangli;Bender, Michael L.
• 通讯作者: Bender, Michael L.