Multicentury records of ENSO and rainfall in corals from northern Australia

ENSO 和澳大利亚北部珊瑚降雨的多世纪记录

• 批准号: 1851587
• 负责人: Julia Cole
• 金额: $ 19.06万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1851587&HistoricalAwards=false
• 关键词: Multicentury; records; ENSO; rainfall; corals

This project integrates two fundamental issues of global environmental change, tropical climate variations and coral reef vitality. By developing linked histories of reef climate and coral growth on the remote northern Great Barrier Reef, this research will illustrate how the region's climate has changed over the past 200+ years and how coral growth has varied in response. Corals in this region can survive for centuries, and a core from the top to the bottom of a long-lived coral colony reveals annual banding that documents the rate of coral growth over that time. The coral's skeletal chemistry tracks the environmental conditions (temperature, salinity, sedimentation) under which the coral grew. Because the corals grow at a rate of a centimeter or more each year, cores can be sampled at a scale of weeks to months to determine short-term (seasonal) as well as long-term (century) trends in growth and environment. The project takes advantage of cores already recovered from northern Australia, where temperature and salinity are closely tied to the state of the El Niño system. El Niño influences climate around the world. This research will help climate scientists understand how El Niño is changing as the world warms and whether recent strong El Niño events are unusual or within the range of natural behavior. By linking the climate record to a history of coral growth from the same core, this project will help coral ecologists to see the connections between climate variations and coral growth rates from seasonal to century time scales. The research includes collaboration with the Australian Institute of Marine Sciences (AIMS), which advises the Australian government on reef management and conservation. By spending a summer at AIMS, a graduate student will receive high-level experience in issues of coral health, growth, and conservation that are critical for managing reefs here in the US as well as abroad. Project participants will engage in interdisciplinary climate research at the University of Arizona, including climate model analysis, the global impacts of El Niño, and communicating their work to a broader audience through public presentations at Biosphere-2. The specific goals of this project include the following:- Use multicentury, subseasonal measurements of coral δ18O and Sr/Ca to define the natural variability of temperature and salinity in this region, and their relationship to regional climate; - Extract seasonally specific histories of El Niño and Australian monsoon rainfall to compare with other records and evaluate for long-term variability; - Compare geochemical histories with luminescent and growth band properties to evaluate agreement and sensitivity as proxies for environmental change; - Use the multivariate information from corals to assess relationships among environmental variations (SST, SSS, and sedimentation) and coral growth (extension, calcification); - Incorporate records into broader analyses of tropical variability, e.g. long-term variations and trends, large-scale patterns, multiproxy syntheses, and comparisons to GCM simulations. This project represents a major advance in climate and coral studies. Despite the long history of coral paleoclimatology, this will be the first integration of geochemical and growth-band characteristics at a subseasonal, multicentury scale. Multiple paleoclimate proxies will yield broadly useful reconstructions of El Niño and monsoon rainfall and reveal how environmental changes influence coral growth. These results will be incorporated into large-scale syntheses to improve understanding of long-term tropical variability. All results will be publically shared with reef managers and other stakeholders, as part of the AIMS mission of science-based conservation, and presented in Arizona to the thousands of visitors that pass through the University of Arizona's Biosphere-2.

该项目综合了全球环境变化、热带气候变化和珊瑚礁生命力这两个基本问题。通过发展偏远的北方大堡礁的珊瑚礁气候和珊瑚生长的相关历史，这项研究将说明该地区的气候在过去200多年来是如何变化的，以及珊瑚生长是如何变化的。这一地区的珊瑚可以存活几个世纪，从一个长寿的珊瑚群落的顶部到底部的核心显示了每年的条带，记录了那段时间珊瑚的生长速度。珊瑚的骨骼化学物质追踪珊瑚生长的环境条件（温度，盐度，沉积）。由于珊瑚每年以一厘米或更高的速度生长，因此可以以几周到几个月的规模对核心进行采样，以确定生长和环境的短期（季节性）和长期（世纪）趋势。该项目利用了已经从澳大利亚北方采集的岩心，那里的温度和盐度与厄尔尼诺系统的状态密切相关。厄尔尼诺现象影响着全球气候。这项研究将帮助气候科学家了解厄尔尼诺现象如何随着世界变暖而变化，以及最近的强厄尔尼诺事件是否不寻常或在自然行为范围内。通过将气候记录与同一岩心的珊瑚生长历史联系起来，该项目将帮助珊瑚生态学家了解从季节到世纪时间尺度的气候变化与珊瑚生长率之间的联系。该研究包括与澳大利亚海洋科学研究所（AIMS）的合作，该研究所为澳大利亚政府提供珊瑚礁管理和保护方面的建议。通过在AIMS度过一个夏天，研究生将获得珊瑚健康，生长和保护问题的高级经验，这些问题对于管理美国和国外的珊瑚礁至关重要。项目参与者将在亚利桑那大学从事跨学科气候研究，包括气候模型分析、厄尔尼诺现象的全球影响，并通过在生物圈二号的公开演讲向更广泛的受众宣传他们的工作。 该项目的具体目标包括&：- 提取厄尔尼诺和澳大利亚季风降雨的季节性特定历史，与其他记录进行比较，并评估长期变化;-将地球化学历史与发光和生长带特性进行比较，以评估作为环境变化代理的一致性和敏感性;- 利用珊瑚的多元信息评估环境变化（SST、SSS和沉积）与珊瑚生长（扩展、钙化）之间的关系; -将记录纳入更广泛的热带变化分析，例如长期变化和趋势、大规模模式、多代理综合以及与GCM模拟的比较。该项目代表了气候和珊瑚研究的重大进展。尽管珊瑚古气候学有着悠久的历史，但这将是第一次在亚季节，多世纪尺度上整合地球化学和生长带特征。多个古气候代理将产生广泛有用的厄尔尼诺和季风降雨的重建，并揭示环境变化如何影响珊瑚生长。这些结果将被纳入大规模的合成，以提高长期的热带变化的理解。所有结果都将作为科学保护的AIMS使命的一部分，与珊瑚礁管理人员和其他利益相关者分享，并在亚利桑那州向通过亚利桑那大学生物圈2号的数千名游客展示。