30 YEARS OF DIATOM STUDIES ON THE GREAT-LAKES AT THE UNIVERSITY-OF-MICHIGAN

Long-term records of biotic populations have proven very important to understanding ecosystem change and its causes. Despite their importanc e, few such records are available, especially for microscopic organism s, and most especially for populations in large lake systems. Circumst ances during the past 30 years allowed development of interpretatively useful information concerning diatom (Bacillariophyta) populations in the Great Lakes system. Here the circumstances, both infrastructure a nd intellectual, which allowed this to take place are reviewed some of the more important insights gained and the evident problems remaining .