Terrestrial Organics since The Oligocene (TOTO): The Rains Down in Africa

渐新世以来的陆地有机物（TOTO）：非洲的降雨今天，近1亿人依赖萨赫勒地区的土地，该地区对洪水，干旱和野火高度敏感，使食物和其他资源处于危险之中。非洲也有丰富的人类进化史，包括早期人类化石遗址，多次从非洲扩散的证据，以及最早的石器创新。尽管该地区对了解气候变化和人类进化具有重要意义，但人们对热带非洲缺乏长期的了解。为此，研究人员将生成过去2500万年来西非降雨、植被和火灾的新记录，以研究萨赫勒生态系统的变化，该生态系统自东向西横跨撒哈拉沙漠以南的非洲，并量化自然周期的影响地球轨道以及全球和区域条件的长期变化对生态系统变化和人类进化的影响。研究人员将召开一次新的非洲气候会议，以促进知识共享，网络活动和拉蒙的实验室图尔斯参观，通过形成深入持久的合作，直接打击西方科学排斥非洲研究人员的长期历史。热带地区占地球表面的一半，是全球水文泵，并含有世界上最大的甲烷潜在来源，然而，对新生代的热带气候缺乏数据和了解。特别是热带非洲，历史上一直研究不足，尽管它的重要性，了解人类进化，热带水文气候，陆地生态系统对气候变化的反应。对未来气候情景的预测需要量化过去对轨道强迫和边界条件的气候响应（即，区域冰量、冰量、全球温度）。研究人员将使用保存在海洋沉积物核心中的生物标志物生成新的长期和高分辨率的降水，植被和火灾重建，这些生物标志物捕获了过去2500万年的热带西非气候。统计和时间序列分析将通过时间来评估水文气候、生态系统和火灾代理之间的振幅、周期性、平均值和关系，以解释研究窗口中变化振幅的差异，从而表征各种边界条件下的敏感性。该项目将为我们最早祖先的进化提供关键的环境背景，并将为这个高度敏感地区未来陆地对全球变暖的反应模型提供信息。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Terrestrial Organics since The Oligocene (TOTO): The Rains Down in AfricaToday, nearly 100 million people depend on the lands in the Sahel region, which is highly sensitive to flooding, droughts, and wildfires, putting food and other resources at risk. Africa is also rich in human evolutionary history, including early human fossil sites, evidence for multiple dispersals out of Africa, and the earliest stone tool innovations. Despite the region’s importance for understanding climate change and human evolution, there is a lack of understanding of tropical Africa over long intervals. To that end, the investigators will generate new West African records of rain, vegetation, and fire over the last 25 million years to study changes in the Sahel ecosystem, which runs east-west across Africa south of the Sahara desert, and to quantify the effects of natural cycles in Earth’s orbit and long-term changes in global and regional conditions on ecosystem change and human evolution. The investigators will convene a new African Climate Conference to facilitate knowledge sharing, networking events, and laboratory tours at Lamont to directly combat the long history of the exclusion of African researchers in Western science by forming deep, lasting collaborations.The Tropics comprise half of Earth’s surface, serve as the global hydrological pump, and contain the world’s largest potential source of methane, yet there is a dearth of data and understanding of tropical climate over the Cenozoic. Tropical Africa, in particular, has been historically under-studied, despite its importance for understanding human evolution, tropical hydroclimate, and terrestrial ecosystem responses to climate change. Projections of future climate scenarios require quantification of past climatic responses to orbital forcings and boundary conditions (i.e., regional albedo, ice volume, global temperature). The investigators will generate new long-term and high-resolution precipitation, vegetation, and fire reconstructions using biomarkers preserved in a marine sediment core that capture the last 25 million years of tropical West African climate. Statistical and time series analyses will evaluate the amplitudes, periodicities, means, and relationships between hydroclimate, ecosystem, and fire proxies through time to decipher the differences in the amplitude of variability in the study windows to characterize sensitivity in the context of various boundary conditions. This project will provide crucial environmental context for the evolution of our earliest ancestors and will inform models of future terrestrial responses to global warming in this highly sensitive region.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.