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

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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.