Nutrient cycling studies have proven valuable in explaining the presence, abundance, and seasonal variation of elements in stream water. The long term objectives of this project are to understand mineral cycling and stream water chemistry of forested watersheds in New Mexico as influenced by vegetational communities, climatic conditions, weathering of soil minerals, and man. Studies to date show water quality changes over elevation, with the lowest concentrations of elements occurring at the highest elevations. This trend is consistent throughout the year; however, actual concentration values vary due to the source of water and seasonal patterns of biological activity. Variation in concentration is greatest at lower elevations. The reasons for the higher concentrations at lower elevations are increased evapotranspiration and a combination of biological controls and bedrock weathering differences. (Modified author abstract)