Validation of the B/Ca proxy for surface seawater pH and application to measure anthropogenic ocean acidification

表层海水 pH 值的 B/Ca 代理验证及其在测量人为海洋酸化中的应用

• 批准号: 0751764
• 负责人: Baerbel Hoenisch
• 金额: $ 33.77万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-03-15 至 2014-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0751764&HistoricalAwards=false
• 关键词: Validation; Ca; proxy; surface; seawater

Arguably, a better knowledge of past natural fluctuations in the earth?s climate and its relation to greenhouse gases will enhance the ability to constrain future impacts on ocean and atmospheric chemistry, and thus global climate change related to anthropogenic additions of CO2. Particular concern exists regarding the potential impact of ocean acidification on marine calcifiers such as corals, pteropods, foraminifers and calcareous algae. The actual extent of ocean acidification since the industrial revolution is still poorly quantified. In this project, researchers at the Lamont Doherty Earth Observatory of Columbia University will study the robustness of a proposed B/Ca paleoproxy through a combination of experimental laboratory cultures and a high-resolution sediment core from the Gulf of Mexico. A pilot study has shown that this proxy has the potential to reflect glacial/interglacial changes of surface seawater pH and atmospheric pCO2. However, the incorporation of boron into planktonic foraminifer shells also seems to be affected by temperature, and salinity variations change the seawater boron concentration. Because pH, temperature and salinity change in unison in the ocean, quantification of the respective effects on B/Ca can only be quantified in the laboratory, were parameters can be singled out. The first step of the proposed research is therefore the proxy validation under controlled conditions in the laboratory. If the quality of the B/Ca proxy is confirmed in laboratory culture and effects can be quantified, B/Ca could have several advantages over the boron isotope/paleo-pH proxy: B/Ca analyses are much faster, require less sample material, and the proxy may not be affected by dissolution in the sediment. In terms of broader impacts, it is clear that the acid-base state of seawater is of fundamental importance to all subdisciplines of oceanography and to a wide variety of global environmental research disciplines. The project will feature multiple inter-institutional collaborations and will provide for the training and support of a graduate student.

可以说，更好地了解地球过去的自然波动？海洋的气候及其与温室气体的关系将增强限制未来对海洋和大气化学的影响的能力，从而限制与人为增加CO2有关的全球气候变化。海洋酸化对珊瑚、翼足类动物、有孔虫和石灰藻类等海洋钙化生物的潜在影响尤其令人关切。自工业革命以来海洋酸化的实际程度仍然很难量化。在该项目中，哥伦比亚大学拉蒙多尔蒂地球观测站的研究人员将通过实验室培养和墨西哥湾高分辨率沉积物岩心的结合，研究拟议的B/Ca古代用品的稳健性。 一项试点研究表明，这一代用指标有可能反映表层海水pH值和大气pCO 2的冰期/间冰期变化。然而，硼的掺入到浮游有孔虫壳似乎也受到温度的影响，盐度的变化改变海水硼浓度。由于pH值、温度和盐度在海洋中一致变化，因此只能在实验室中量化对B/Ca的各自影响，其中参数可以单独列出。因此，拟议研究的第一步是在实验室受控条件下进行代理验证。如果B/Ca代用品的质量在实验室培养中得到证实，并且效果可以量化，则B/Ca可能比硼同位素/古pH代用品具有几个优点：B/Ca分析快得多，需要的样品材料少，并且代用品可能不受沉积物中溶解的影响。就更广泛的影响而言，海水的酸碱状态显然对海洋学的所有分支学科和各种各样的全球环境研究学科都具有根本的重要性。 该项目将以多个机构间合作为特色，并将为一名研究生提供培训和支持。