This study is one of the first true ecosystem studies in that it is designed to study the succession of biological stream colonization. A multi-disciplined approach is being taken to study every aspect of stream colonization. Glacier Bay National Park and Preserve (GBNPP), Alaska, provides an ideal living laboratory because, due to rapid glacial recession, there are a number of similar-sized streams in the area of varying ages. This serves as a surrogate for time. The basic experimental design, then is to measure a wide variety of physical and biological variables at a number of streams representing different successional stages. By measuring numerous characteristics, we can detect interactions between different ecosystem components and determine the critical stages of succession.