P2C2: Long-term Environmental Changes and Anthropogenic Impacts on Tropical African Landscapes

非技术摘要本奖项授予格鲁吉亚州立大学，将研究气候变化、植被变化和人类对非洲热带环境影响的长期历史。研究人员将分析东非湖泊和沼泽沉积物核心中的碳和氮同位素、花粉化石、硅藻、真菌孢子和木炭。了解东非的气候和植被变化具有重要意义，因为它为研究热带气候系统的变异性打开了一扇窗户。该项目将以必要的时间分辨率和足够的精确度重建东非的环境，以揭示过去10，000年气候变化背后的因果机制。该项目的一个重要科学目标是调查过去在塑造东非环境方面人为影响与气候变化模式的相互作用。具体而言，该研究旨在回答以下问题：在过去10，000年中，人类对环境造成影响的证据出现在记录中的时间点是什么？太阳活动周期和长距离气候事件的变化在多大程度上解释了东非气候和环境随时间的变化？最后，在过去的4,500年里，人类对环境的影响是否取代了东非的自然气候变化趋势？该项目有望提供重要的数据，更广泛地了解环境变化及其与气候的关系，并为更好地了解人类与气候的相互作用提供背景。该项目更广泛的影响包括支持研究生，促进肯尼亚当地的能力建设，并通过合作研究和联合出版物与肯尼亚的科学家进行国际合作。技术摘要识别人类与气候相互作用的动态仍然是人类悬而未决的问题之一。该项目的目的是研究气候变化的历史，植被的变化，和人类对非洲热带环境的影响，在全新世通过检查的岩石地层学，化石花粉，硅藻，真菌孢子和微观木炭在湖泊沉积物芯的多代理记录。湖泊和沼泽环境中保存的地球化学、生物和沉积记录为过去气候变化和人为影响所造成的环境变化提供了极好的档案，这些档案可以揭示自然环境如何应对未来与人类有关的气候变化。了解东非的气候和植被变化意义重大，因为它为研究热带气候系统及其因果机制的变异性打开了一扇窗户，迄今为止，这些变异性在很大程度上仍未得到解决。该项目将采用多代用指标方法，以必要的时间分辨率和足够的精度重建东非的古环境，通过分析肯尼亚西部Kanyaboli湖（维多利亚湖的卫星湖）和Saiwa沼泽的岩芯，揭示全新世晚期气候变化背后的因果机制。 该项目的重要目标包括：根据对从湖泊和沼泽环境中收集的沉积物岩心的分析，制作东非地区全新世晚期高时间分辨率多代用古环境记录;了解东非环境变化时空变异的控制机制及其与太阳活动和遥相关事件的可能联系;通过采用涉及地球化学物种、花粉、真菌学数据、硅藻和微观木炭的多代理方法，将东非景观中人类引起的变化与气候变化引起的变化隔离开来;确定人类活动对环境的影响并确定其发生时间，探索其与非洲热带地区环境变化的关系，将调查的科学问题是跨学科性质的，将涉及对了解人类活动对地球物理过程和古环境变化的影响至关重要的问题。这项研究有望提供重要的数据和更广泛地了解环境变化及其与气候的关系，并为更好地了解人类与气候的相互作用提供背景。 该项目更广泛的影响包括支持研究生，促进肯尼亚当地的能力建设，以及通过合作研究和联合出版物与肯尼亚科学家进行国际合作。

Non-Technical AbstractThis award to Georgia State University will study the long-term history of climate change, vegetational changes and human impacts on tropical African environments. The investigator will analyze carbon and nitrogen isotopes, fossil pollen, diatoms, fungal spores, and charcoal in lake and swamp-sediment cores from East Africa. Understanding climate and vegetational change in East Africa is significant because it opens a window for studying the variability of tropical climate systems. This project will reconstruct East Africa's environment with the necessary time resolution and sufficient precision to reveal the causal mechanisms behind the climate changes during the last 10,000 years. An important scientific goal of the project is to investigate the interaction of human-induced impacts and the pattern of climate change in shaping East Africa's environment in the past. Specifically, the study seeks to answer the following questions: At what point during the the last 10,000 years does the evidence of human-induced impacts on the environment appear in the record? To what extent does variability in the solar cycle and long-distance climate events explain changes in East Africa's climate and environment through time? And lastly, does the human-induced imprint on the environment supplant natural climatic change trend in East Africa during the last 4,500 years? The project holds the promise of providing important data and a broader understanding of environmental change and its relation to climate, and provides a context for better understanding the interplay of humans and climate. The broader impacts of the project include supporting graduate students, contributing to local capacity building in Kenya, and international collaboration with scientists in Kenya through collaborative research and joint publications.Technical AbstractDiscerning the dynamics of human-climate interaction remains one of humanity's eminent unanswered questions. This project aims to study the history of climate change, vegetational changes, and human impacts on tropical African environments during the Holocene through the examination of a multi-proxy record of the lithostratigraphy, fossil pollen, diatoms, fungal spores, and microscopic charcoal in lake-sediment cores. Geochemical, biological, and sedimentary records preserved in lacustrine and palustrine environments provide an excellent archive of past changes in the environment resulting from both climate changes and anthropogenic impacts which could reveal how the natural environment may respond to human-related climate change in the future. Understanding climate and vegetational change in East Africa is significant because it opens a window for studying variability in tropical climate systems and their causal mechanisms which, to date, remain largely unresolved. This project will use a multi-proxy approach to reconstruct East Africa's paleoenvironment with the necessary time resolution and sufficient precision to reveal the causal mechanisms behind the climate changes during the late Holocene through analysis of cores from Lake Kanyaboli (a satellite of Lake Victoria) and Saiwa Swamp in western Kenya. The important goals of the project include: producing a high-temporal-resolution multi-proxy paleoenvironmental record of the late Holocene for the East African region based on analysis of sediment cores collected from lacustrine and palustrine environments; understanding the control mechanisms for the spatial and temporal variability of environmental changes in East Africa and their possible linkage to solar activity and teleconnection events; isolating human-induced changes in the East African landscapes from the changes due to climate variations by employing the multi-proxy approach involving geochemical species, pollen, mycological data, diatoms, and microscopic charcoal; and identifying and dating the onset of anthropogenic impacts on the environment and exploring their relationship with environmental changes in the tropical African region.The scientific issues that will be investigated are interdisciplinary in nature and will address questions which are important to understanding the impacts of human activities on geophysical processes and paleoenvironmental change. The research holds the promise of providing important data and a broader understanding of environmental change and its relation to climate, and provides a context for better understanding the interplay of humans and climate. The broader impacts of the project include supporting graduate students, contributing to local capacity building in Kenya, and international collaboration with scientists in Kenya through collaborative research and joint publications.