In the decade since the first edition of this book was published advances have been made in our knowledge of the fresh waters of the world, espe cially in understanding many of the processes involved in their functioning as systems and in countering the problems created by human activities. New problems too, many of an international nature, have loomed during this period-of which global warming and the acidification offresh waters in many parts of the world are notable examples. In addition, much has now been published concerning the aquatic flora, fauna and ecology of previously poorly known geographic areas, notably Australasia. The second edition of this book is a revision which updates the text in the light of recent advances in our knowledge of freshwater biology. Inevitably, in an elementary volume such as this, the treatment of many of the basic principles and processes remains the same. However, several new sections are included covering a range of topics such as acid deposition and the acidification process, bacterial decomposition and aquaculture. The book includes many new references and suggestions for up-to-date reading in particular topics. The objective of the second edition remains the same as that of the first. It is intended as a basic introduction to the major aspects of freshwater biology at a level suitable for undergraduates. It should also prove useful, as apparently did the first edition,Jo professional workers in related fields, e.g. water engineers and chemists, aquaculturists and planners.

This established textbook continues to provide a comprehensive andstimulating introduction to rivers, lakes and wetlands, and waswritten as the basis for a complete course on freshwater ecology.Designed for undergraduate and early postgraduate students who wishto gain an overall view of this vast subject area, this accessibleguide to freshwater ecosystems and man's activities will also beinvaluable to anyone interested in the integrated management offreshwaters. The author maintains the tradition of clarity andconciseness set by previous editions, and the text is extensivelyillustrated with photographs and diagrams. Examples are drawn fromthe author's experience in many parts of the world. In this edition, the scientific content of the text has beenfully revised and updated. Emphasis has been placed on humanimpacts, and a completely new chapter has been added on the futureof freshwaters. Balanced and stimulating introduction to limnology. Successfully combines fundamental and applied aspects ofintegrated management of freshwaters, with strong emphasis on humanlinks. Completely revised and rewritten with a threefold increase inthe number of illustrations. New chapter on the future of freshwaters. Of interest to undergraduates, beginning postgraduates and anylimnologically interested reader.

This book brings together research into the process of stream acidification and its impact on Welsh surface waters, carried out over the past decade or so. It is perhaps surprising that not until the 1980's was clear evidence of stream acidification assembled. In Wales, concerns over pollution had focused water quality sampling principally on the areas of traditional heavy industry and large urban popula tions served by inadequate sewerage systems and sewage disposal arrange ments. Mistakenly, it had been assumed that, with its prevailing westerly winds, Wales would receive precipitation substantially unpolluted by the industrial and urban emissions from Britain and mainland Europe. Assurance of the high quality of Welsh upland streams, the traditional nursery ground of salmonids, was eroded particularly by studies in the vicinity of Llyn Brianne reservoir in the catchment of the River Tywi of Central Wales. These demonstrated a clear correspondence between the biological quality and fisheries of streams in the catchment and aspects of stream chemistry, par ticularly pH, aluminium and calcium on the one hand, and catchment land use on the other. It is salutary to record that the first signals were of an inexplicable failure of the runs of migratory salmonids into the upper catchment, occupied by the Llyn Brianne reservoir and its influent streams, and the failure to restore the fishery by re-stocking with eggs and fry. Only then did the significance of the recent decline in some other upland lake and reservoir fisheries in Wales become apparent.

"awareness" of the world's citizens and encourage governments to devote more attention and resources to address this issue. The series editors thank the international panel of contributors for bringing this timely series into completion. We also wish to acknowledge the very insightful input of the following colleagues: Prof. A.L. Page of the University of California, Prof. T.C. Hutchinson of the University of Toronto, and Dr. Steve Lindberg of the Oak Ridge National Laboratory. We also wish to thank the superb effort and cooperation of the volume editors in handling their respective volumes. The constructive criticisms of chapter review ers also deserve much appreciation. Finally, we wish to convey our appreciation to my secretary, Ms. Brenda Rosier, and my technician, Ms. Claire Carlson, for their very able assistance in various aspects of this series. Aiken, South Carolina Domy C. Adriano Coordinating Editor Preface to Acidic Precipitation, Volume 1 (Advances in Environmental Science) As a result of pioneering research in the 1960s and because of the perceived and acidic real environmental effects described during the ensuing years, the terms rain, acidic deposition, or acidic precipitation have become commonplace in the scientific and popular literature. In the last decade, governments throughout the world have responded to public pressure and to the concerns of the scientific community by establishing research programs on national and international scales.

Providing a wealth of reference material for research scientists and policy makers, these proceedings address the extremely complex problem of acidification - a phenomenon which is causing serious deterioration of natural environments in Europe and North America. Papers review the effects of acidification on the aquatic environment, flora, fauna and vegetation, and materials, and also review cultural properties, the ecology as a whole and the economic impact of acidification. The papers on forest-dieback cover potential stress factors and the effects on materials and cultural properties. Scientific research results are presented which deal with models as tools for abatement strategies, and underline the application of models in policy-making. The review papers of scientific research on acidification are followed by the official report of the conference, and presentations by representatives of the EEC member countries giving an overview of national research programmes and policies regarding acidification.