Dissertation Research: The El Nino Southern Oscillation and Glacial Juniperus Physiology

厄尔尼诺南方涛动(ENSO)是热带太平洋大气压力和海面温度变化引起的一种气候模式。虽然ENSO气候模式只直接影响热带地区，但对温度和降水的间接影响遍及全球。在理解目前的ENSO活动方面已经取得了重大进展，但ENSO在改变的环境条件下(过去和未来)的行为和影响尚不清楚。在加利福尼亚州南部，厄尔尼诺现象产生了一个更温暖、更潮湿的生长季节，导致刺柏生长加速，年轮中沉积的木材化学成分发生了变化。这项研究将分析保存在拉布里亚焦油坑中的刺柏年轮的宽度和化学特征，以确定过去50,000年来厄尔尼诺现象的强度和频率。此外，还将分析厄尔尼诺和非厄尔尼诺年份冰川时代和现代树木的生长模式，以评估这些气候模式是如何影响树木生长的。通过扩大对ENSO事件在更长时间段内的频率、强度和影响的理解，这项研究将为理解气候波动的生态反应提供更好的背景。该项目将整合到堪萨斯大学和附近的约翰逊县社区学院(JCCC)之间的现有合作中。项目资助为JCCC学生提供研究经验，包括样本收集、准备、数据分析和传播。学生还将在一个专业会议上介绍这项研究，这将为建立网络和接触科学研究和教育机会提供充足的机会。

The El Niño Southern Oscillation (ENSO) is a climatic pattern resulting from changes in air pressure and sea surface temperatures in the tropical Pacific Ocean. Though the ENSO climate pattern directly affects only the tropics, indirect effects on temperature and precipitation are experienced throughout the globe. Significant progress has been made in understanding current ENSO activity, but the behavior and effects of ENSO under altered environmental conditions (both past and future) are not known. In southern California, El Niño conditions produce a warmer and wetter growing season, resulting in increased growth of juniper trees and altered chemical make up of wood deposited in annual rings. This study will analyze the width and chemical signature of rings from juniper trees preserved in the La Brea tar pits to determine the strength and frequency of El Niño years throughout the last 50,000 years. Additionally, growth patterns of glacial-aged and modern trees in El Niño and non-El Niño years will be analyzed to assess how these climatic patterns affected tree growth.By extending understanding of the frequency, strength, and effects of ENSO events over a much longer time period this study will provide an improved context for understanding ecological responses to climatic fluctuations. This project will be integrated into an existing collaboration between Kansas University and nearby Johnson County Community College (JCCC). Project funding provides research experience for a JCCC student, including sample collection, preparation, data analysis and dissemination. The student will also present the research at a professional conference, which will provide ample opportunities for networking and exposure to opportunities in science research and education.