These proceedings deal with the relationship between species composition of freshwater phytoplankton and the trophic gradient. Particular regard is paid to the composite question, what lives where and why? Overview papers report the state of the art and suggest that the trophic spectrum appears to be a probabilistic outcome of several dimensions of variability that impinge upon phytoplankton species selection. Studies on community structure span all latitudes from those of Antarctica to equatorial Brazil, and also include reports on light and nutrient gradients, pH and fish-stock effects on species composition. Seasonal and longterm phytoplankton dynamics in lakes of varying trophic status are also considered. Finally, studies on the taxonomy and autoecology of some groups (e.g. Volvocales, Chrysophytes and Euglenophytes) living at the extremes of the trophic spectrum contribute to our knowledge of this usually neglected phytoplankton. This is the first time that a book covers such a topic, and it will prove an excellent source of information to anyone working on phytoplankton ecology and ecological indicators. Limnologists in general, algologists and the technical staff at water authorities will all benefit by reading this book.

Lake Ladoga is the largest lake in Europe and, with its surface of 17,891 km2 and volume of 837 km3, it ranks among the top fifteen of the world's freshwater bodies. The ecological condition of Lake Ladoga is of concern to several million people living in its surroundings. There is evidence of water quality degradation and gradual eutrophication of the lake during the past decades; on the other hand, pollution control measures have improved the situation in many of the most polluted sites near industrial effluent sources. The first international Lake Ladoga Symposium was held in St. Petersburg on 22-26 November, 1993. The symposium was attended by 160 scientists, and about half of the papers presented at the symposium have been edited for this book. The contributions are grouped under the following headings: Present state of Lake Ladoga; Hydrodynamics of Lake Ladoga and other large water bodies; Water quality and pollution; Ecological studies of Lake Ladoga biota; History of Lake Ladoga and rates of change in its environment; Research methods for large lakes. Besides providing up-to-date information on the state of the lake, the papers deal with studies of many other large lakes of the cold-temperature zone and the general problems and methods of large lake research. Furthermore, the book is a valuable source of reference to the voluminous Russian limnological literature.

This volume is a collection of papers concerning the biology of large branchiopod crustaceans: Anostraca, Conchostraca, and Notostraca. Many of the individual papers were first presented at the Third International Large Branchiopod Symposium (ILBS-3) held at the University of San Diego, CA, USA, July 15-18, 1996. Contributions on additional topics from participants at the symposium, and from colleagues not able to join us in San Diego, are also included. In addition, there is a supplement to the 1995 Checklist of the Anostraca'. The theme of the ILBS-3 was understanding and conserving large branchiopod diversity'. Researchers from around the world presented papers on a variety of topics related to conservation of large branchiopods, with contributions ranging from alpha-taxonomy and zoogeography to community structure and studies of ecology and evolution. One important issue developed in many of the papers in this volume is the need to advance our understanding of basic aspects of branchiopod biology throughout the world in order to enhance our efforts to conserve them. Although we have made important strides in understanding the biology of large branchiopods, we have, with few notable exceptions, made little progress in assuring the conservation of their diversity. We hope this volume will supply the reader with new ideas, and generate enthusiasm for research and public education efforts on behalf of branchiopod conservation.

For the first time, an effort to conduct coordinated interdisciplinary research on a vast and complex saline lake has been undertaken for the purposes of providing baseline data to guide restoration project activities. This volume compiles state-of-the-art science for the Salton Sea and will serve as the foundation for the next several generations of scientific inquiry for California's largest lake. The science presented here reveals the Salton Sea to be one of the most productive fisheries in the world, details why the Salton Sea is important to migratory and wintering birds, investigates the microbial world and reports numerous taxa new to science, and documents chemical and physical interactions which make this inland saline lake function.
This book is intended for specialists in saline lake research who are interested in all aspects of saline lake ecology.

stable or falling water levels, and permit differen tiation between gradual and sudden transgression The level of Lake Ontario was long assumed to of the shoreline. Vegetational succession reflects have risen at an exponentially decreasing rate shoreline transgression and increasing water solely in response to differential isostatic rebound depth as upland species are replaced by emergent of the St. Lawrence outlet since the Admiralty aquatic marsh species. If transgression continues, Phase (or Early Lake Ontario) 11 500 years B. P. these are in turn replaced by floating and sub (Muller & Prest, 1985). Recent work indicates merged aquatic species, commonly found in water that the Holocene water level history of Lake to 4 m depth in Ontario lakes, below which there Ontario is more complex than the simple rebound is a sharp decline in species richness and biomass model suggests. Sutton et al. (1972) and (Crowder et al., 1977). This depth varies with Anderson & Lewis (1982, 1985) indicate that physical limnological conditions in each basin. periods of accelerated water level rise followed by Because aquatic pollen and plant macrofossils are temporary stabilization occurred around 5000 to locally deposited, an abundance of emergent 4000 B. P. The accelerated water level rise, called aquatic fossils reflects sedimentation in the littoral the 'Nipissing Flood', was attributed to the cap zone, the part of the basin shallow enough to ture of Upper Great Lakes drainage. support rooted vegetation."

This book tells a story of a large lake affected by agricultural and urban activities that have led to severe eutrophication problems with nuisance blue-green algal blooms. Although it is a case study of Lake Ringsjoen (southern Sweden), the background, problems and measures are applicable to many lakes throughout the world. From a limnological point of view, the Lake Ringsjoen story began more than 100 years ago, and during the last 20 years the sampling program has been intense, providing a unique data set on how a lake responds to human activities. However, the Lake Ringsjoen story is not only a case study, but also a historical record of the development of ecological theory and its application. Hence, the lake has been subject both to an extensive nutrient reduction programme and a biomanipulation by means of fish reduction. Here we aim at combining the unique limnological data set with the eutrophication process, the nutrient reduction programme and the biomanipulation in order to apply our empirical knowledge to future lake management measures.

If present trends continue, most climatologists agree that the concentration of carbon dioxide in the atmosphere will have doubled by the year 2050. This increase in CO 2 will have a major effect on the global climate and substantially alter the physical, chemical and biological characteristics of lakes throughout the world. In recent years, it has become clear that year-to-year changes in the weather have a major effect on the seasonal dynamics of lakes. Many water quality problems that were once regarded as "local" phenomena are now known to be influenced by changes in the weather that operate on a regional or even global scale. For example, blooms of toxic blue-green algae can be induced by prolonged reductions in the intensity of wind-mixing as well as increased supplies of nutrients. Long-term studies in the English Lake District have shown that many of these variations are quasi-cyclical in nature and can be related to long-term changes in the distribution of atmospheric pressure over the Atlantic Ocean. It is not yet clear what effect these changes have on the dynamics of European lakes but much of the historical data required to extend these analyses to continental Europe is already available. In the early 1970s the International Biological Programme served as a particularly effective focus for comparative limnological research in eastern as well as western Europe.

Lake Titicaca, because of its area and volume and its situation at high attitude within the tropics, is a unique hydrological site in the world. It should be noted that it stands at the transition point between two very distinct geographical regions: the desert fringe of the Pacific coast to the west and the great Amazonian forest extending to the Atlantic coast to the east. Many scientists have been attracted to the lake in the past because of its unusual limnological features. In this book the editors have compiled an exhaustive review of current knowledge from the existing literature and from the results of more recent observations. It is certain that this book will become the essential reference work for scientists wanting to make progress in revealing the lake's secrets. It can be stated unequivocally that this work constitutes a complete review of the present state of knowledge on Lake Titicaca and that it provides the latest results of research on this habitat.

Twenty years ago, researchers wishing to identify contaminated areas in aquatic environments generally took water samples, and analysed them badly (as we have since discovered) for a few "pollutants" which were of topical note at the time (and which could be quantified by the methods then available). Today, the use of aquatic organisms as biomonitors in preference to water analysis has become commonplace, and many national and interna tional programmes exist around the world involving such studies. We believe that this trend will continue, and have complete faith in the methodology (when it is employed correctly). We hope that the following text assists in some part in attaining this goal, such that the quality of our most basic global resource -water - is adequately protected in the future. DAVE PHILLIPS, PHIL RAINBOW England, March 1992 vii Acknowledgements Our thanks for contributions to this book are due to several individuals and groups, for varying reasons. Firstly, a co-authored book is always a triumph, and we trust that the following text is an acceptable compromise of the views of two individual authors, on a complex and developing topic. Secondly, many of the ideas herein have crystallised over the last two decades as the field has grown, and we are individually and collectively grateful to a number of researchers for their insight and assistance."

This volume is derived from a symposium on High Latitude Limnology held during the 23rd Congress of the Societas Internationalis Limnologiae in Hamilton, New Zealand. The symposium stemmed from our belief that an exchange of views between limnologists working in the north and south polar zones would be timely and productive. Over the last decade there has been a major increase in the limnological research effort in Antarctica with the expansion of science programmes there by many nations from both the northern and southern hemispheres. Freshwater research has also continued to develop in the Arctic, stimulated by the need for basic information to assess environmental impacts of the oil industry, mining, urbanisation and other human activities. By bringing together aquatic investigators from both poles we hope to draw attention to the distinctive features that high latitude systems hold in common, and to the marked contrasts between and within each zone. The dominant impression from the assemblage of papers presented here is one of great limnological diversity. The studies include clear, turbid and brown water rivers in the sub Arctic (LaPerriere, Van Nieuwenhuyse & Anderson); chlorophyte dominated streams in the maritime Antarctic (Hawes); streams on the antarctic continent lined with thick cyanobacterial mats (Howard-Williams & Vincent); meromictic waters in the Arctic (Ouellet, Dickman, Bisson & Page) and Antarctic (e. g.

Cell signalling lies at the heart of many biological processes and currently is the focus of intense research interest. In multicellular organisms, it is central to how different types of cell communicate with each other and how they detect and respond to extracellular signals. Intercellular communication is vital to single-celled organisms as well, allowing them to respond to environmental cues and signals.

To date, much of the understanding of signalling mechanisms has come from research on specific cell types (eg mouse lymphocyte and cardiomyocyte) or on organisms in which communication systems such as nervous and endocrine systems are well established. This volume therefore aims to 'fill the gap' by concentrating on 'simple organisms' where the elements of those signalling systems first evolved. Many of the groups covered contain important pathogens or parasites, and the potential for manipulating signalling pathways for therapeutic intervention will be highlighted.

Concentrations of dissolved organic matter (DOM) in lakes are often an order of magnitude greater than concentrations of particulate organic matter; nevertheless, the biogeochemical analysis of DOM is described in only a few textbooks on limnology (most thoroughly by Wetzel). The orgins of dissolved organic substances are largely photosynthetic; DOM is either autochthonously synthesized by littoral and pelagic flora through secretions and autolysis of cellular contents, or allochthonously generated in terrestrial systems of the drainage basin, composing largely of humic substances refractory to rapid microbial degradation. The role of DOM in lacustrine ecosystems, as energy source and system regulator, however, is still poorly known. The aim of this book is: (1) to present state-of-the-art reviews of the role of dissolved autochthonous and allochthonous organic matter in pelagial and littoral zones; and (2) to focus attention on poorly understood but critical topics and hence to provide direction for future research activity.

Estuaries exist along the edge of the oceans and seas, and are char acterized by the dilution of sea water by inflowing fresher waters. The motion and interaction of these two types of water (fresh and salt water) determine the salinity distribution within the estuary and that, in turn, affects the organisms residing there. The purpose of this vol ume is to review the status of our understanding of estuarine circu lation and how the circulation patterns affect living and nonliving resources in estuaries. For many years, the primary paradigm for estuarine circulation was the two-layered net or nontidal gravitational circulation pattern first proposed by Dr. Donald Pritchard in his studies of the James River estuary. During the last decade or so, research has focused on the many variations about this theme and the factors that control the transport processes. Many of these aspects are covered in the initial papers in this volume. Water movement, of course, is of interest be cause it transports marine organisms, sediments, and pollutants. Es tuarine circulation has a significant effect on estuarine food chains, and on the distribution and abundance of organisms, such as the American oyster, that are freely transported by the currents during larval stages. The intent is to bring together many of these topics in a single volume. This volume is dedicated to Dr. Donald W."

'The criterion of true beauty', wrote Fulke Greville, 1st Baron of Burke, 'is that it increases on examination; if false, that it lessens. There is therefore something in true beauty that corresponds with right reason, and it is not the mere creation of fantasy.' The authors of this compact volume have increased the beauty of an area that is commonly and rightly ac knowledged to be one of the loveliest parts of the Great Lakes. They have done this by integrating the historical, industrial, and cultural influences on 'Lake Manitoulin' in sixteen manuscripts. It is enigmatic that Lake Huron, the second of the Great Lakes to be discovered by European explorers, has been the last to be adequately described Iimnologicaliy. As recently as 1966, for example, Alfred M. Beeton wrote in Limnology in North America: ' ... even a list of the more common species comprising the plankton of Lake Huron could be an original contribution to scientific literature.' Comparable statements could have been made for sediments, benthos, and water chemistry. This volume reflects a change of course and Georgian Bay and the North Channel of Lake Huron are now on the scientific map. Science is 'right reason'. Its application to Georgian Bay and the North Channel is a welcome and timely addition for the renewal of public, political, and scientific interest in the conservation of the Great Lakes."

This volume contains papers presented either in oral or poster form at the international symposium Limnology of Mountain Lakes', held at Stara Lesna (Slovakia) between 1 and 7 July 1991. Several papers covered contributions from the fields of physical and chemical limnology, palaeolimnology, zooplankton, phytoplankton and phytobenthos, and bacteria. Acidification, a process affecting water chemistry and biota of many mountain lakes in Europe was dealt with also. A series of papers on the lakes in Sumava has highlighted different aspects of these lakes, which are in the last stage of acidification. Other geographical areas covered extensively were the Tatras and the Alps. "

This new series on The Biochemistry and Molecular Biology of Fishes grew out of the demand for state-of-the-art review articles in a rapidly expanding field of research. Up to the present, most research literature on biochemistry involved rats and humans, but new breakthroughs in the piscine setting have indicated that the field is ready for a review series of its own. Because of funding and experimental availability restrictions, most research in the field has dealt with fish and insects. Within the insect field, comparative biochemistry and comparative physiology have proceeded along independent paths as opposed to the piscine field, where the tendency has been for the latter to envelop the former.
This volume sets out to make comparative biochemistry and comparative physiology independent of each other within the piscine setting, another important rationale for this review series as well as detailing the phylogenetic evolution of fishes. The goal of the series is to provide researchers and students with an appropriate balance between experimental results and theoretical concepts.

Providing a synthesis of basic and applied research, The Everglades, Florida Bay, and Coral Reefs of the Florida Keys: An Ecosystem Sourcebook takes an encyclopedic look at how to study and manage ecosystems connected by surface and subsurface water movements. The book examines the South Florida hydroscape, a series of ecosystems linked by hydrology in a region of intense human development and profound modifications to the natural environment.

The book presents scientific studies in the South Florida Hydroscape, discusses policy and management by government and nonprofit groups, and explores how the whole watershed approach must be used to successfully protect coral reefs. The contributions range from the traditional to the controversial, questioning current management schemes and summarizing the results of state-of-the-art research.

Billions of dollars, countless man-hours, and innumerable resources have been spent studying the various South Florida ecosystems and how they are linked. The Everglades, Florida Bay, and Coral Reefs of the Florida Keys: An Ecosystem Sourcebook shows you how the principles learned in this region can be applied to other tropical and subtropical hydroscapes.

The Middle Parana river is one of the largest in the world. Exceptionally rich in fauna and flora, it provides researchers with a glimpse into an ecosystem yet undisturbed by human civilization. This fascinating book covers all the key aspects of the Parana s fluvial limnology and ecology, arranged in discrete and easily navigable sections. First, the physical and chemical environment is explained, then the river s plant life, followed by its invertebrate life, and finally the vertebrates that inhabit the river.

Crater Lake is located in the caldera of Mount Mazama in Crater Lake National Park, Oregon. The lake has a surface area of about 53 km2 at an elevation of 1882 m and a maximum depth of 594 m a" seventh deepest in the world. Limited studies of this ultraoligotrophic lake conducted between 1896 and 1981, lead to a 10-year limnological study to evaluate any potential degradation of water quality. No long-term variations in water quality were observed that could be attributed to anthropogenic activity. Building on the success of this study, a permanent limnological program has been established with a long-term monitoring program to insure a reliable data base for use in the future. Of equal importance, this program serves as a research platform to develop and communicate to the public a better understanding of the coupled biological, physical, and geochemical processes in the lake and its surrounding environment.

This special volume represents our current state of knowledge of the status of this pristine ecosystem including its special optical properties, algal nutrient limitations, pelagic bacteria, and models of the inter-relationships of thermal properties, nutrients, phytoplankton, deep-water mixing, and water budgets.

Ecotones are interface zones between different ecosystems. Their ecological role and significance with regard to ecological management and conservation has become increasingly appreciated. For the management of freshwater resources, for example, an improved understanding of the role of land/inland water interfaces, will be essential for reducing negative human impacts by engineering, nutrient loading, siltation, etc. The management of ecotones, on the other hand, offers the possibility to control aquatic system processes via stock control of fish populations. Fish apparently are both excellent indicators of ecotone quality as well as determiners of its structure and function.

This book examines the application of fish community characteristics to evaluate the sustainability and biological integrity of freshwaters. Topics include perspectives on use of fish communities as environmental indicators in program development, collaboration, and partnership forming; influence of specific taxa on assessment of the IBI; regional applications for areas where the IBI had not previously been developed; and specific applications of the IBI developed for coldwater streams, inland lakes, Great Lakes, reservoirs, and tailwaters.

There is increasing concern in the media, among politicians and within environmental organizations, about the effects of chemicals in our environment that affect the endocrine systems of wildlife and humans. At its simplest these are referred to as gender-bending' chemicals or environmental estrogens'. The chemicals in question (pesticides, PCBs, plasticizers, petrochemicals, and a variety of industrial chemicals) have been known to decrease human sperm counts, cause fish to change sex', and increase male genital abnormalities. A great deal of pressure has been placed on environmental protection agencies to devise regulatory tests for the effects of these chemicals and to require limitations on their manufacture and release. Fish are increasingly recognized as an excellent model for such tests, in that the aquatic environment may provide early warnings of the effects that these chemicals will have on human health. In addition, the large number of eggs which fish produce provides an excellent model to examine the effects on female fertility. Endocrine Disruption in Fish provides a simple yet extensive background to the field of fish endocrinology in order to assist those toxicologists who have a limited background in either mammalian or fish endocrinology. It shows that environmental estrogens do not simply affect male reproductive potential, but that they may equally well affect the female. It is possible that these chemicals may have a complex effect on the brain, hypothalamus, pituitary, gonad and liver of both sexes. There are many other chemicals which affect both the gonads and other parts of the endocrine system to cause decreased fertility, abnormal sexual differentiation andbehavior, decreased response to stress, immune deficiency or altered basal metabolism. Many thousand man-made chemicals are released into the environment, but very few have been tested for endocrine disrupting activity. This book covers only the minute fraction for which evidence has been collected.

Preface. Water and Society. Bacterial and Microbial Processes. Phytoplankton Dynamics and Community Structure. Productivity and Energy Flows. Fish and Fisheries. Interactions between Tropic Levels. Monitoring and Modelling. Water Pollution and Water Management. Concluding Remarks. Index.

Obituary: Edward Smith Deevey (1914-1988).- Palaeolimnology in the English Lakes - some questions and answers over fifty years.- Accuracy and precision in sediment chronology.- 241Am dating of lake sediments.- Accuracies in Po-210 determination for lead-210 dating.- How long was the Younger Dryas? Preliminary evidence from annually laminated sediments of Soppensee (Switzerland).- Absolute dating of late Quaternary Lacustrine sediments by high resolution varve chronology.- The record of deposition of radionuclides in the sediments of Ponsonby Tarn, Cumbria.- Deposition and transport of radionuclides within an upland drainage basin in mid-Wales.- Progress in understanding the chemical stratigraphy of metals in lake sediments in relation to acidic precipitation.- Spheroidal carbonaceous particles as a marker for recent sediment distribution.- Magnetic spherules in recent lake sediments.- Lake sediment records of erosional processes.- A multidisciplinary study of the lake Bjaresjoesjoen (S Sweden): land-use history, soil erosion, lake trophy and lake-level fluctuations during the last 3000 years.- Paleolimnology of Slapton Ley, Devon, UK.- Sequential inorganic chemical analysis of a core from Slapton Ley, Devon, UK.- Sediment characteristics in relation to cultivation history in two varved lake sediments from East Finland.- The influence of land use on the sedimentation of the river delta in the Kyroenjoki drainage basin.- Heavy metals (Cu and Zn) in recent sediments of Llangorse Lake, Wales: non-ferrous smelting, Napoleon and the price of wheat - a palaeoecological study.- A comparative study of heavy metal contamination and pollution in four Reservoirs in the English Midlands, UK.- Sedimentary diatom concentrations and accumulation rates as predictors of lake trophic state.- The sediment column as a record of trophic status: examples from Bosherston Lakes, SW Wales.- Recent changes to upland tarns in the English Lake District.- Palaeolimnological study of an environmental monitoring area, or, Are there pristine lakes in Finland?.- The eutrophication history of Lake Sarkinen, Finland and the effects of lake aeration.- Are we building enough bridges between paleolimnology and aquatic ecology?.- Weichselian chironomid and cladoceran assemblages from maar lakes.- Stratigraphy of the fossil Chironomidae (Diptera) from Lake Grasmere, South Island, New Zealand, during the last 6000 years.- Modern assemblages of arctic and alpine Chironomidae as analogues for late-glacial communities.- Paleolimnology of Neusiedlersee, Austria: the succession of ostracods.- Palaeolimnology of Neusiedlersee - II: the distribution of nutrients and trace metals.- Paleolimnological investigation of three manipulated lakes from Sudbury, Canada.- Dominant diatoms in the interglacial lake sediments of the Middle Pleistocene in Central and Eastern Poland.- Fossil diatom inferred reconstruction of the pH history of two acidic, clear water lakes from insular Newfoundland, Canada.- Taphonomy and diagenesis in diatom assemblages; a Late Pleistocene palaeoecological study from Lake Magadi, Kenya.- Palaeolimnological aspects of a Late-Glacial shallow lake in Sandy Flanders, Belgium.- Palaeolimnological studies of laminated sediments from the Shropshire-Cheshire meres.- Paleolimnological studies using sequential lipid extraction from recent lacustrine sediment: recognition of source organisms from biomarkers.- Vegetation change and pollen recruitment in a lowland lake catchment: Groby Pool, Leics (England).- Seasonal changes in sedimenting material collected by high aspect ratio sediment traps operated in a holomictic eutrophic lake.- Paleolimnology of a Polar Oasis, Truelove Lowland, Devon Island, N.W.T., Canada.- An environmental history of two freshwater lakes in the Larsemann Hills, Antarctica.- Paleolimnology of Qilu Hu, Yunnan Province, China.- Sedimentary features and the evolution of lake Honghu, central China.- Palaeolakes of the south central Sahara - probl