COLLABORATIVE RESEARCH: SEA-LEVEL RISE AND SALT-MARSH RESPONSE: A PALEO PERSPECTIVE

合作研究：海平面上升和盐沼响应：古视角

• 批准号: 1322918
• 负责人: Benjamin Horton
• 金额: $ 11.35万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1322918&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; SEA; LEVEL; RISE

Accurate projections of future relative sea-level (RSL) rise are crucial for effective management of coastal populations, infrastructure, and ecosystems including salt marshes. Sea-level reconstructions from the last 4000 years provide a context for understanding modern and projected rates of sea-level rise because Earth's climate system is relatively unchanged. We will develop two new proxy RSL reconstructions from North Carolina to identify positive and negative departures from the perceived stability of sea level during the last 4000 years and support development of new predictive models in which the sea level-climate relationship can vary through time. The reconstructions will test the widely held assumption that sea-level rise from melting of large ice sheets was negligible during the last 2000 years and will help constrain rates of vertical land level movement. Data generated for the reconstructions will be used to further develop a model of salt-marsh response to sea-level rise that will provide a valuable service and tool to the coastal management community for informing policy decisions. While there are compilations of global and regional proxy temperature data for the late Holocene, little is known about sea-level variability during this period and the response of sea level to known climate deviations such as the Medieval Climate Anomaly, Little Ice Age, and 20th century warming is unknown. Using foraminifera preserved in North Carolina salt-marsh sediments, we will produce the first continuous, high resolution (decadal and decimeter) RSL reconstruction spanning the last ~4000 years. The sea-level reconstructions will calibrate new predictive models of sea-level rise to improve the accuracy and regional validity of projections. The new record will extend existing reconstructions to test the following hypotheses that are vital for understanding the climate sea-level relationship: (1) regional RSL was stable before AD 1000; and (2) the contribution from melting of large ice sheets sea-level rise ended 2000 years ago. Reconstructions derived from salt marsh sediment also provide a paleo perspective for predicting the ecological effects of future sea-level rise. The proxy sea-level record will validate, for the first time, the Marsh Equilibrium Model (MEM). The MEM describes the regulation of salt-marsh vegetation by changes in sea level. If sea-level rise is faster than the rate of salt-marsh sediment accretion, the productivity of salt-marsh vegetation will decline, resulting in the degradation or loss of these important coastal ecosystems. The proxy sea level record will test a central premise of the MEM that (3) Stable sediment organic matter (SOM) concentration varies inversely with the reconstructed rate of RSL-rise.

准确预测未来相对海平面 (RSL) 上升对于有效管理沿海人口、基础设施和包括盐沼在内的生态系统至关重要。过去 4000 年的海平面重建为了解现代和预计的海平面上升速度提供了背景，因为地球的气候系统相对没有变化。 我们将开发来自北卡罗来纳州的两个新的代理 RSL 重建，以识别过去 4000 年中与海平面感知稳定性的正偏差和负偏差，并支持开发新的预测模型，其中海平面与气候关系可以随时间变化。重建工作将检验人们普遍持有的假设，即过去 2000 年中大冰盖融化导致的海平面上升可以忽略不计，并将有助于限制陆地平面垂直移动的速度。重建产生的数据将用于进一步开发盐沼对海平面上升的响应模型，该模型将为沿海管理界提供宝贵的服务和工具，为政策决策提供信息。 虽然有全新世晚期全球和区域代理温度数据的汇编，但人们对这一时期的海平面变化以及海平面对已知气候偏差（例如中世纪气候异常、小冰河时代和20世纪气候偏差）的响应知之甚少。世纪变暖是未知的。利用北卡罗来纳州盐沼沉积物中保存的有孔虫，我们将进行首次连续、高分辨率（十年和分米）RSL 重建，跨越过去约 4000 年。海平面重建将校准新的海平面上升预测模型，以提高预测的准确性和区域有效性。新记录将扩展现有的重建，以检验以下对于理解气候海平面关系至关重要的假设：（1）区域RSL在公元1000年之前是稳定的； (2)大冰盖融化对海平面上升的贡献在2000年前就结束了。来自盐沼沉积物的重建也为预测未来海平面上升的生态影响提供了古视角。代理海平面记录将首次验证马什均衡模型（MEM）。 MEM 描述了海平面变化对盐沼植被的调节。如果海平面上升速度快于盐沼沉积物增加的速度，盐沼植被的生产力就会下降，导致这些重要的沿海生态系统的退化或丧失。代理海平面记录将检验 MEM 的一个中心前提：(3) 稳定沉积物有机质 (SOM) 浓度与 RSL 上升的重建速率成反比变化。