Collaborative Research: Multi-proxy sea-level reconstructions and projections in the middle Pacific Ocean

合作研究：中太平洋多代理海平面重建和预测

• 批准号: 1831450
• 负责人: Robert Kopp
• 金额: $ 8.27万
• 依托单位: Rutgers University New Brunswick
• 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: 2018-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1831450&HistoricalAwards=false
• 关键词: Collaborative; Research; Multi; proxy; sea

Reconstructions of relative sea-level from geological archives such as coastal sediment offer insight into sea-level changes on a range of geographic (local, regional, and global) and time (years to millennia) scales. These reconstructions can be leveraged to constrain the long-term, pre anthropogenic components of sea-level change, which must be quantified to produce projections of future sea-level rise needed to build resilience in coastal communities. Observational records are too short to perform this task and existing reconstructions spanning the past ~5000 years are primarily located at sites around the North Atlantic Ocean. There is a scarcity of records from the tropical Pacific Ocean, in part due to a lack of sites with suitable coastal sediment. Confounding the lack of data in the tropical Pacific Ocean is the heightened vulnerability of small island nations to the consequences of sea level rise. This project will produce near-continuous reconstructions of relative sea-level change during the past ~5000 years using sediment that was deposited in mangrove swamps in the Federated States of Micronesia (FSM; Chuuk, Pohnpei, Kosrae). Incorporation of the results into a statistical framework will allow regional-scale projections of relative sea level change in FSM during the 21st and 22nd centuries to be developed. These projections will be shared with stakeholders in FSM (e.g., federal and state government agencies and non-governmental organizations) to help plan for future sea level rise. Multi-disciplinary training will also be provided to undergraduate and graduate students and a postdoctoral scientist.Mangrove swamps have a systematic and quantifiable relationship to tidal elevation, as do micro-organisms such as foraminifera that live on the sediment surface in mangroves and leave a fossil record. This ecological preference for specific elevations makes mangrove sediment and foraminifera valuable sea-level proxies. As relative sea level rises, mangrove swamps accumulate sediment to preserve their elevation in the tidal frame. Over 100s to 1000s of years, multi-meter sequences of sediment are deposited that can be collected and studied to reconstruct relative sea level. In much of the tropics, however, long-term sea-level fall prohibits the accumulation of sediment. Crucially, long-term tectonic subsidence in FSM has resulted in near-continuous accumulation of mangrove peat over the past ~5000 years. This project will recover sediment cores in FSM and establish a history of sediment accumulation through radiocarbon dating and recognition of pollution and land-use changes of known age in downcore elemental and isotopic profiles. Foraminifera preserved within the buried sediment will be used to estimate the height of former sea-level through quantitative comparison of fossil assemblages with modern analogs. The new reconstructions will be combined with an existing (and updated) database of late Holocene relative sea-level reconstructions to estimate global mean sea-level trends using an existing spatio-temporal model. This model will also facilitate partitioning of the relative sea level signal into its constituent parts to better understand the causes of local, regional, and global trends on short (decadal) and long (multi century) timescales. Using a statistical framework that incorporates multiple sources of uncertainty and accounts for simultaneous and co varying contributions from regional scale processes (e.g., meltwater fingerprints and/or ocean dynamics), this research will produce relative sea-level projections for FSM that will be shared directly with key local stakeholders.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

从沿海沉积物等地质档案中的相对海平面的重建提供了对一系列地理（本地，区域和全球）以及时间（千年）尺度的海平面变化的见解。可以利用这些重建来限制海平面变化的长期人为成分，必须量化这些变化，以产生未来海平面上升的预测，以建立沿海社区的弹性。观察记录太短了，无法执行这项任务，并且过去约5000年的现有重建主要位于北大西洋周围的地点。热带太平洋的记录稀缺，部分原因是缺乏适当的沿海沉积物的地点。在热带太平洋中缺乏数据的困惑是小岛国家对海平面上升后果的脆弱性。该项目将在过去的5000年中使用沉积物沉积在密克罗尼西亚联邦（FSM; Chuuk，pohnpei，kosrae）中的红树林沼泽中，对过去约5000年进行相对海平面变化的重建。将结果纳入统计框架将允许开发21和22世纪FSM相对海平面变化的区域尺度预测。这些预测将与FSM（例如联邦和州政府机构和非政府组织）的利益相关者共享，以帮助计划未来的海平面上升。还将向本科生和研究生和博士后科学家提供多学科培训。Mangrove沼泽与潮汐高程有系统的，可量化的关系，微生物（如有孔虫）也是如此记录。 这种对特定海拔的生态偏好使红树林沉积物和有孔虫有价值的海平面代理。随着相对海平面的上升，红树林沼泽会积聚沉积物，以保留其在潮汐框架中的海拔。在超过100至1000年的时间里，可以沉积多米的沉积物序列，可以收集并研究以重建相对海平面。然而，在许多热带地区，长期的海平面下降禁止沉积物的积累。至关重要的是，FSM中的长期构造沉降导致过去约5000年的红树林泥炭几乎连续积累。该项目将在FSM中恢复沉积物核心，并通过放射性碳年代测定以及对下侧元素和同位素剖面中已知年龄的污染和土地利用变化的认识来建立沉积物积累的历史。保存在埋藏的沉积物中的有孔虫将通过定量比较现代类似物的化石组合来估计以前海平面的高度。新的重建将与现有（且更新的）相对海平面重建的现有（且更新的）数据库结合使用，以使用现有的时空模型来估计全球平均海平面趋势。该模型还将促进将相对海平面信号分配到其组成部分中，以更好地理解短（十年）和长（多世纪）时标的本地，区域和全球趋势的原因。使用一个统计框架，该框架结合了多种不确定性来源，并说明了区域尺度流程（例如，融化融合指纹和/或海洋动力学）的同时和共同贡献，这项研究将为FSM产生相对的海平面投影，这些预测将直接共享该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和更广泛的影响标准来评估值得支持的。

项目成果

A statistical framework for integrating nonparametric proxy distributions into geological reconstructions of relative sea level

将非参数代理分布整合到相对海平面地质重建中的统计框架

• DOI: 10.5194/ascmo-8-1-2022
• 发表时间: 2022
• 期刊: Meteorology and Oceanography
• 作者: Ashe, Erica L.;Khan, Nicole S.;Toth, Lauren T.;Dutton, Andrea;Kopp, Robert E.
• 通讯作者: Kopp, Robert E.