In: Diatoms: Ecology and Life Cycle ISBN: 978-1-61761-979-3 Editors: James C. Compton ©2011 Nova Science Publishers, Inc. Chapter 8 PROBLEMS AND POTENTIALITIES OF USING DIATOMS AS P ALEOCLIMATIC INDICATORS IN CENTRAL ARGENTINA Gabriela S. Hassan*, Eleonor Tietze, Claudio G. De Francesco and Paula A. Cristini CONICET - Instituto de Geología de Costas y del Cuaternario, Universidad Nacional de Mar del Plata. Mar del Plata, Buenos Aires, Argentina. ABSTRACT Paleoclimatologists advocate learning from the past to know the natural and anthropogenically induced climatic shifts that occurred in the history of the Earth, and to estimate future changes in ecological systems related to the projected range of temperature increases. Framed within this context, current rates of global warming are unprecedented based on the last 10,000 years of paleoclimatological evidence. Diatom analysis has played a major role in the reconstruction of these past climate changes, bringing evidences of water and air temperature fluctuations, as well as of climatically driven variations in water chemistry variables. Most of these evidences came from North American and European records, while the number of studies in South America has been considerably lower. Hence, many questions regarding the natural climatic cycles and the strength of human induced changes remain unanswered for vast regions of South America. In Central Argentina, the occurrence of many shallow lakes with sedimentary records encompassing the last 10,000 years, as well as outcropping alluvial sequences of Late Pleistocene and Holocene origin, provide good opportunities for studying these topics. Moreover, the diverse ranges of temperature and precipitation that characterize this region would allow studying the patterns of distribution of modern diatom assemblages against climatically driven environmental variables, as well as to assess the potential application of these modern datasets to the quantitative reconstruction of past climates. In this chapter, we analyze the problems and potentialities regarding to the application of the modern diatom data to assess past climate changes in central Argentina. The main objective is to identify particular lines of research that need to be addressed in * Corresponding author: E-mail: ghassan@conicet.gov.ar