RAPID: Galapagos lake chemistry and plankton assemblage during the 2015-16 El Nino

RAPID：2015-16 厄尔尼诺期间加拉帕戈斯湖化学和浮游生物组合

• 批准号: 1608241
• 负责人: Julian Sachs
• 金额: $ 7.5万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-12-15 至 2017-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1608241&HistoricalAwards=false
• 关键词: RAPID; Galapagos; lake; chemistry; plankton

Robust reconstructions of tropical Pacific climate are critically important for understanding past climate change due to the unique ability of this region to influence climate on a global scale. The El Niño-Southern Oscillation (ENSO) affects precipitation and temperature patterns across more than half of the globe every 3-7 years. Impacts associated with ENSO include drought, flooding, crop failure, disease, and changes in ocean productivity. Importantly, large uncertainties exist regarding how ENSO has changed in the past and how it is likely to change in a higher CO2 world. Improving ENSO reconstructions from the vastly under-sampled eastern equatorial Pacific will help elucidate the response of ENSO to large-scale changes in the climate system and thus poses tremendous benefit to society. Freshwater and coastal saline lake sediments in the Galápagos Islands provide invaluable long continuous reconstructions of rainfall from the eastern equatorial Pacific, where annual rainfall is strongly correlated to El Niño sea surface temperatures. To date, however, such reconstructions have been hampered by large uncertainties owing to the lack of direct measurements of the response of Galápagos lakes to El Niño conditions.This project seeks to leverage the 2015-2016 strong El Niño event that is currently underway to improve constraints on these and future rainfall reconstructions from the tropical Pacific. Towards this end, a comprehensive set of meteorological and lake measurements will be taken at El Junco Lake (San Cristobal Island) and Poza del Diablo and Poza Verde (Isabela Island) during the onset, peak, and decay phase of the El Niño event in collaboration with Equadorian scientists and the Charles Darwin Research Station. Measurements will include hydrologic fluxes (precipitation, evaporation) and their isotopic composition (d2Hrain), as well as physical, chemical, and biological properties of the lakes (d2Hlake, temperature, salinity, nutrients, pH, phytoplankton assemblage, depth, and d2H of plant and algal biomarkers). These data will enable the relationship between modern climate and the paleoclimate proxies to be explicitly evaluated through the course of a rare strong El Niño event (the last of which occurred 18 years ago). This dataset would be the most comprehensive characterization of the influence of El Niño events on these lake systems to date and would greatly advance ongoing efforts to construct quantitative paleo-ENSO records from this region. The work is supported by Marine Geology and Geophysics, Earth Sciences Global Change, and the Office of International Science and Engineering.

热带太平洋气候的可靠重建对于了解过去的气候变化至关重要，因为该区域具有在全球范围内影响气候的独特能力。厄尔尼诺Niño-Southern涛动（ENSO）每3-7年影响全球一半以上地区的降水和温度模式。与ENSO相关的影响包括干旱、洪水、作物歉收、疾病和海洋生产力的变化。重要的是，关于ENSO在过去是如何变化的，以及在二氧化碳含量更高的世界中它可能会如何变化，存在很大的不确定性。改进赤道东太平洋极低采样的ENSO重建将有助于阐明ENSO对气候系统大尺度变化的响应，从而为社会带来巨大的利益。Galápagos岛屿上的淡水和沿海盐湖沉积物提供了宝贵的赤道东太平洋降雨的长期连续重建，那里的年降雨量与El Niño海面温度密切相关。然而，迄今为止，由于缺乏对Galápagos湖泊对El Niño条件的反应的直接测量，这种重建受到了很大的不确定性的阻碍。该项目旨在利用目前正在进行的2015-2016年强厄尔尼诺Niño事件来改善这些和未来热带太平洋降雨重建的限制。为此目的，将与赤道科学家和查尔斯·达尔文研究站合作，在El Junco湖（圣克里斯托瓦尔岛）、Poza del Diablo和Poza Verde（伊莎贝拉岛）在El Niño事件的开始、高峰和衰减阶段进行一套全面的气象和湖泊测量。测量将包括水文通量（降水、蒸发）及其同位素组成（d2rain），以及湖泊的物理、化学和生物特性（d2lake、温度、盐度、营养物质、pH、浮游植物组合、深度以及植物和藻类生物标志物的d2H）。这些数据将使现代气候和古气候代用物之间的关系能够通过一次罕见的强厄尔尼诺Niño事件（最后一次发生在18年前）的过程得到明确的评估。该数据集将是迄今为止厄尔Niño事件对这些湖泊系统影响的最全面表征，并将极大地推进正在进行的从该地区构建定量古enso记录的工作。这项工作得到了海洋地质与地球物理、地球科学全球变化和国际科学与工程办公室的支持。