Based on the classic ecosystem studies at Hubbard Brook in New Hampshire, this book presents an in-depth analysis of the biogeochemistry of a terrestrial ecosystem. It synthesizes more than 30 years of data on precipitation and stream-water chemistry, hydrology, and weathering, and also considers the role of atmospheric gases and water as they flow through the system. The book illustrates ways in which ecosystems are affected by three major biogeochemical vectors of the Earth: air, water, and animals. In turn, it shows how an ecosystem moderates and changes inputs, and how it is connected to global biogeochemical cycles by its outputs. <P>The book illustrates that ecosystem control over biogeochemical functions is highly predictable and discusses the factors that cause change from year to year. Research at Hubbard Brook is recognized internationally as a model for conducting long-term studies in ecology. Hailed in its first edition as a "standard for ecological teaching and research for years to come" (Quarterly Reviews of Biology), this revision brings the Hubbard Brook Ecosystem Study up to date and makes it available to a new generation of ecologists and environmental scientists in a concise, highly reasonable synthesis. <P>Gene E. Likens is director of the Institute of Ecosystem Studies in Millbrook, New York. F. Herbert Bormann is professor emeritus at the School of Forestry and Environmental Studies at Yale University. The authors won the 1993 Tyler Prize, the World Prize for environmental achievement, for their work at Hubbard Brook.