Environmental Change and Response in East African Lakes

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.