The Burning Question: How did fire shape Eastern Africa’s paleo-ecosystem?

这个项目的范围是探索火灾在塑造东非生态系统动态中的基础作用。为此，该项目使用了埃塞俄比亚Chew Bahir湖280米长的复合沉积序列，该序列跨越了约62万年。分析框架检查和量化化石宏观和微观木炭颗粒，从而深入了解从轨道到次千年尺度的火灾严重程度和频率。木炭颗粒的形态计量学分析将进一步使我们能够深入了解与Chew Bahir接壤的地区的植被组成。由于湖泊记录中花粉保存较差，这将是一个重大的进步。此外，我们将在木炭颗粒上应用新的显微镜下FTIR光谱技术，实现火灾温度的重建。木炭丰度和植被记录将使我们能够破译火灾发生、植被组成和潜在的人为相互作用之间的关系，从而全面了解生态恢复机制和早期人类适应。使用统计技术将使我们能够全面调查木炭记录与潜在气候强迫（例如，二氧化碳或日照变化）之间的关系。我们进一步探索可能存在的非线性关系，这可能表明该地区人类活动的增加。将此与现有的东非木炭记录相结合，将提供对该地区历史火灾动态的全面时空理解。为了进一步推进火灾温度重建的新技术，我们将在Chew Bahir地区的野外工作中收集有代表性的植被样本，生成一个参考数据库。收集的标本将在受控条件下燃烧，随后作为重建整个记录的火灾温度的基准。了解火灾温度对于重建过去的野火制度至关重要(例如，“冷”阴燃火灾与“热”森林火灾)，为了解历史火灾的强度和行为及其对生态系统和气候变化的潜在影响提供了见解。总而言之，该项目将提供东非热带地区最长和时间分辨率最高的陆地木炭记录及其首个火灾温度记录。通过研究全球火灾历史的先进方法，该项目将为火灾对生态系统的生态影响提供新的见解，这与未来预测的变化和我们物种的发展有关。

This project's scope is to explore the foundational role of fire in shaping Eastern Africa's ecosystem dynamics. For this purpose, the project uses the 280-meter-long composite sedimentary sequence of Chew Bahir Lake (Ethiopia), spanning c. 620,000 years. The analytical framework examines and quantifies fossil macro and micro-charcoal particles, enabling insights into fire severity and frequency across orbital to sub-millennial scales. Morphometric analyses of the charcoal particles will further allow us to gain insights into the vegetational composition of the region bordering Chew Bahir. This would be a significant advancement due to the poor pollen preservation in the lake record. Additionally, we will apply the novel technique of microscope-enabled FTIR spectroscopy on charcoal particles, enabling the reconstruction of fire temperature.The charcoal abundance and vegetation records will allow us to decipher the relationships between fire occurrences, vegetal compositions, and potential anthropogenic interactions, thus yielding a comprehensive understanding of ecological resilience mechanisms and early human adaptations. Using statistical techniques will enable us to comprehensively investigate the relationship between charcoal records and potential climate forcings (e.g., CO2 or insolation changes). We further aim to explore the possible presence of non-linear relationships that might indicate increasing human activities within the region. Combining this with existing East African charcoal records will provide a comprehensive spatiotemporal understanding of the historical fire dynamics in the area.To further advance the novel technique of fire temperature reconstruction, we will generate a reference database of representative vegetation samples collected during a fieldwork campaign in the region of Chew Bahir. The collected specimens will be combusted under controlled conditions and subsequently serve as a benchmark for reconstructing fire temperatures across the entire record. Understanding fire temperatures is crucial for reconstructing past wildfire regimes (e.g., "cold" smoldering fires vs. "hot" forest fires), providing insights into the intensity and behavior of historical fires and their potential impact on ecosystems and climate change.In summary, this project will provide the longest and temporally highest-resolved terrestrial charcoal records from tropical Eastern Africa and its first fire temperature record. By advancing methodologies for examining fire histories globally, this project will offer novel insights into the ecological impact of fire on ecosystems over time, relevant to future projected changes and the development of our species.