For the past 4 billion years, the chemistry of the Earth's surface, where all life exists, has changed remarkably. Historically, these changes have occurred slowly enough to allow life to adapt and evolve. In more recent times, the chemistry of the Earth is being altered at a staggering rate, fueled by industrialization and an ever-growing human population. Human activities, from the rapid consumption of resources to the destruction of the rainforests and the expansion of smog-covered cities, are all leading to rapid changes in the basic chemistry of the Earth. The Second Edition of "Biogeochemistry" considers the effects of life on the Earth's chemistry on a global level. This expansive text employs current technology to help students extrapolate small-scale examples to the global level, and also discusses the instrumentation being used by NASA and its role in studies of global change. With the Earth's changing chemistry as the focus, this text pulls together the many disparate fields that are encompassed by the broad reach of biogeochemistry. With extensive cross-referencing of chapters, figures, and tables, and an interdisciplinary coverage of the topic at hand, this text will provide an excellent framework for courses examining global change and environmental chemistry, and will also be a useful self-study guide. It emphasizes the effects of life on the basic chemistry of the atmosphere, the soils, and seawaters of the Earth. It calculates and compares the effects of industrial emissions, land clearing, agriculture, and rising population on Earth's chemistry. It synthesizes the global cycles of carbon, nitrogen, phosphorous, and sulfur; and suggests the best current budgets for atmospheric gases such as ammonia, nitrous oxide, dimethyl sulfide, and carbonyl sulfide. It includes an extensive review and up-to-date synthesis of the current literature on the Earth's biogeochemistry.