RESUMO
Fossil diatoms from a sediment core of Lake Yambo, a lake in an endorheic, desert region of the Ecuadorian Andes, provide a record of precipitation events that can be linked to the ENSO phenomenon. Abnormally high precipitation in the region during the 1982-83 El Niño caused a substantial drop in the lake's conductivity. The diatom flora in the lake changed from a community dominated by the halophilic species Craticula halophila, to one dominated by a fresh water species Aulacoseira distans. Similar shifts in dominance can be seen at various points throughout the core. There also appears to be an increase in sediment deposition at these points. This paper provides tha first evidence that the use of fossil diatoms from lake cores can be a valuable tool in reconstructing histories of El Niño events (AU)