The International Decade for the East African Lakes (IDEAL) has completed its first phase of field studies, and has assembled in this volume its findings, ranging from seismic reflections to historical drought chronologies, geochemistry, and modern food web processes. Multidisciplinary IDEAL investigations are summarized and integrated, revealing that modern changes in the East African lakes share a continuity with past variations in climate and environmental conditions. Results from an array of disciplinary perspectives and evidentiary lines point to the causative role of modern climate variation in the deterioration of Lake Victoria, one of the most prominent lakes on the planet. The ancient conditions of Victoria and other East African lakes are reconstructed with forensic tools that permit measurements of paleomagnetism, pollen and algal fossils, biogenic minerals, depositional carbonates, and bulk geochemistry. Oral traditions, explorer's journals, and records of the ancient Nile provide human testimonies that parallel the physical record. Studies of biological production, nutrient dynamics, and lower food web processes reveal how the lake communities function at the trophic levels that leave sedimentary evidence in the form of organic matter, minerals, and fossils. Comparisons of weather records and lake properties demonstrate a striking change in climate conditions during the present century with causal links to lake conditions. The collected scientific perspective makes a compelling case for the worth of integrated studies across a spectrum of traditional specialties when they are focused on complex environmental issues.

The idea for this book was born at the June 1996 meeting of the IDEAL Steering Committee in Milwaukee, Wisconsin. We had just completed a successful and stimulating special symposium during the annual meeting of the American Society for Limnology and Oceanography, and enthusiasm was running high for the production of a volume that could assemble in one place the scientific findings that were starting to emerge from East Africa. IDEAL, an International Decade for the East African Lakes, had ended one round of field investigations, many of which had been centered on Lake Victoria. As the climatologists, geologists, paleolimnologists, and biologists displayed their results and debated interpretations, it appeared that some paradigms were shifting, and that new explanations of climate history and modem processes were taking shape. The Steering Committee endorsed the production of a volume that would draw together the different research results that were emerging and which would be representative of the scope of science issues that exist within IDEAL. This book follows in the spirit of The Limnology, Climatology, and Paleoclimatology of the East African Lakes, published in 1996, but has a somewhat different purpose. The previous publication also included original science results, but it was conceived to review the state of knowledge, identify critical problems, and point to new paths of inquiry. It accompanied the development of our first Science and Implementation Plan for the East African Lakes.