Long-term population monitoring is an important tool in our investigations of the role waterbirds play in their environment. This book is international in scope and presents information on species as diverse as the Common Loon, Harlequin Duck, and Semi-Palmated Sandpiper, and habitat in locations ranging from Iceland to Japan. Papers presented in this volume further our understanding of the important role that limnology plays in determining habitat suitability for waterbirds.

Birds are an integral part of most freshwater ecosystems (lakes, rivers, wetlands) but their role in the trophic dynamics of these water bodies has often been overlooked. As a conspicuous part of the biota of water bodies, aquatic birds are indicators of their trophic state both in terms of species composition (quality) as well as occupancy and breeding (quantity). Birds may also influence the trophic state of a water body by importing nutrients (.e.g. resident or migrating birds feeding on adjacent watersheds or the sea). Because of anthropogenic activities, predation or their mobility, birds may not utilize otherwise suitable aquatic habitat. These factors complicate the relationship between aquatic bird production and the trophic status of habitats. As a consequence, the role of aquatic birds in freshwater ecosystems has usually been ignored. This volume contains a wide range of papers selected from those presented at the symposium and reviewed.

This book IS an attempt to review the state-of-the-art in the fields of limnology and of marine biology in the Sudan. The need for it became apparent while we were doing some joint field work in the Nile Valley and along the Red Sea coast. We feel that several reasons justify its publication. Firstly, a vast amount of information is being gathered year after year by the staff of the Hydrobiological Research U nit of the University of Khartoum, in conjunction with the faculties of Medicine and Agriculture of this university; much of this information fails to find an outlet to the scientific literature. Secondly, we did not want to restrict our book to the Nile Valley. The Nile is such a vital life artery to the Sudan that it has dominated limnological efforts in this country, to the neglect of other geographical areas. The same holds true for the field of marine biology, which lags far behind, despite the existence of a marine field laboratory at Suakin and a research institute at Port Sudan. It is hoped that both will develop considerably in the near future.

Limnology provides an in-depth and current overview of the field of limnology. The result of a major tour de force by two renowned and experienced experts, this unique and richly illustrated reference presents a wealth of data on limnology history, water as a substrate, lakes' origins and aquatic biota. Besides a general part, it gives special focu

The volume starts with comparative reservoir limnology and deals with problems relating to tropical, semi-arid and temperate reservoirs. The second part concerns mathematical models of reservoirs, including new techniques for investigating their limnology. These cover physical, chemical and biological phenomena, remote sensing and the use of modelling to establish the most efficient strategy for water quality sampling. In the third, on reservoir water quality management, the potential available in fish population management for biomanipulation of reservoir water quality is introduced. Also included is a valuable section on a wide range of water quality measures, coming from the well-known Czech Hydrobiological Laboratory. Finally the editors summarise the present state of reservoir limnology. This book will be of interest to hydrobiologists and aquatic ecologists, reservoir and sanitary engineers, fisheries officers, postgraduate teaching, and the water industry dealing with drinking water supply and will provide insight into regulated rivers. It draws information from all over the world and is relevant to the whole world.

Australia is the world's driest inhabited continent. Water is our limiting resource. It might therefore be thought that our water resources would be the subject of the most intensive study. Certain aspects, it must be conceded, have received much attention, notably the availability of water in terms of actual quantity. The size of the surface water and the groundwater resource is well understood and indeed receives about as much study as can reasonably be expected in a country with as sparse a population and level of scientific manpower as ours. Although the importance of understanding the water resource in terms of quantity is widely accepted, what has not been generally appreciated is that for this resource to be 'available' to human society for all the different uses to which it is put, it is not sufficient that there exists within easy reach of the end users a certain total volume of water. For that water to fulfil its functions-for agriculture, industry, the home, recreation, biological conservation-it must be in a certain state: it must conform to certain chemical, physical and biological criteria, and what has not been sufficiently appreciated in Australian society is that the condition a water is in depends very much on the ecology of the waterbody in which it resides. There are waterbodies in the world, for example high-altitude glacial lakes, which are naturally so pristine that their water could be used for any purpose without treatment.

The present volume comprises aspects of both basic and applied limnology. They include works on physical, chemical, and biological limnology, as well as experimental approaches in selected areas. Contributions from investigators regarding aquatic conservation and biodiversity were specifically not available and therefore, these aspects are considered in various included works. Most manuscripts deal with lentic aquatic resources. This is not surprising since Mexican limnology followed the general study trend of that from temperate limnology. Despite this, we must emphasize that lotic resources in Mexico are quite important both locally and regionally. This does not mean that rivers are not under limnological research in Mexico, just that their study has only recently begun. It is the intention of the volume to stimulate a larger section of limnologists to further research in this field. It is to be hoped that policy-framing governmental authorities in Mexico will benefit from it, and consider some of the aspects described so that further damage to the epicontinental waterbodies can be halted, and remedial measures can be considered in the future.

Limnology is the study of the structural and functional interrelationships of organisms of inland waters as they are affected by their dynamic physical, chemical, and biotic environments. Limnology: Lake and River Ecosystems, Third Edition, is a new edition of this established classic text. The coverage remains rigorous and uncompromising and has been thoroughly reviewed and updated with evolving recent research results and theoretical understanding. In addition, the author has expanded coverage of lakes to reservoir and river ecosystems in comparative functional analyses.