R. Gilles – författare

When I was asked to organize this symposium on marine producti­ vity, it made me reflect on what aspects of this subject would be stimulating to a heterogeneous group of laboratory-oriented physiolo­ gists and biochemists. In recent years there have been several books which discusses the methodology commonly used in primary production studies and described the magnitude of photosynthetic CO reduction 2 in various areas of the world's oceans. I therefore decided to dis­ pense with these conventional aspects of primary production and invite researchers to speak on a variety of problems relating the abundance and activity of phytoplankton to environmental conditions. The lectures I invited were thus quite diverse in character, but all were related either to factors affecting the rate of photosynthesis or to the fate of reduced carbon as it passes through the microbial food web. In addition to these talks the participants benefited from a number of shorter presentations and poster sessions which dealt with production and cycling of organic carbon in the marine environment. February 1984 Osmund HOLM-HANSEN CONTENTS 1. Factors Governing Pelagic Production in Polar Oceans E. SAKSHAUG and O. HOLM-HANSEN •. ••. ••••. . . . . . •. •••. . ••••. •. •••• 1 2. Productivity of Antarctic Waters. A Reappraisal S. Z. EL-SAYED •. . . ••••••••. . •••. •. •••••••••. •••. •. •. . . . •. . . . •. 19 3. A Thermodynamic Description of Phytoplancton Growth D. A. KIEFER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 4. Mechanisms of Organic Matter Utilization by Marine Bacterio­ plankton 45 F. AZAM and J. W.

A wealth of information on osmotic and ionic reaulation in Estuarine and Marine Animals has been accumulated over the past decades. Beyond early studies of whole-animal responses to changes in envi- ronmental salinities, efforts have been made later on to identify, to localize and to characterize the organs and structures responsible for the control of the characteristics of the cell's environmental fluid. When considering the problem of cell volume control in animals facing media of fluctuating salinities, we are indeed dealing with two different categories of mechanisms. A first one is concerned with the control of the osmolality of the intracellular fluid, hence with the processes directly implicated in the maintenance of cell volume and shape. They have been extensively described in several recent review papers. The second category includes the processes controllin~ the charac- teristics of the cell's environmental fluid in order to minimize the amplitude of the osmotic shocks the cells may have to cope with upon acclimation to media of changed salinities. They are localized in particular organs and structures : the so-called "caZt-transporting" epithelia.Up to now, most of the studies on salt-transportino epithe- lia in estuarine and marine animals used the black box approach, so that little or sometimes nothing is still known on the physiological, the biochemical and the biophysical basis of the transporting mecha- nisms as well as on the structure-function relationships.

The aim of this symposium was to provide a framework for fruitful discussion on intestinal transport, not only for advanced scientists but also for younger people starting in this field of research. Invited lectures, communications and poster presentations were focused on four central themes, all treating the prop­ erties of the sole intestinal epithelium, deliberately leaving aside problems dealing with more integrative functions of the whole intestine. The importance of motility or blood circulation, for instance, is certainly capital in the overall intestinal function, but these aspects by themselves deserve another meeting. This volume has compiled the manuscripts of the invited lectures which sub­ stantially comprised the four sessions of the Symposium. Part 1 is designed to emphasize actual knowledge of the transport of water, inorganic as well as organic ions and molecules across the isolated intestinal epithelium. An enormous wave of investigations has emerged from studies per­ formed with "Ussing chambers", which roused interest in studies on absorption mechanisms and subsequently on secretory processes. This has triggered off a trend to research on isolated cells as absorption and secretion are the main func­ tion of the different cell types constituting the intestinal epithelium. In this first session not only the importance of the parallel arrangement of these different cellular entities is stressed, but also the role played by the paracellular route.

During the last decade, the study of behavioural endocrinology has gone through a very exciting phase. New technologies have appeared which have allowed us to answer new questions; the present book is a reflection of this progress. In the eariy1970's, the advent of steroid radioimmunoassays (RIA) for the first time permitted measurement of gonadal and adrenal steroids in small aliquots of plasma. It thus became possible to measure these hormones repeatedly in the same animals (Le., to undertake longitudinal studies) and also to assay them in small-sized animals such as the rat or the ring dove which had traditionally been favourite subjects for behavioural endocrinologists. With the RIA's, two major goals have been achieved. On one hand, it has been possible to ascertain that those hormones, whose action on behaviour had been postulated on the basis of gonadectomy and hor- mone therapy experiments, were actually present in adequate amounts in the intact animals at the time they were supposed to exert their ac- tion. On another hand, it has become feasible to measure the circulat- ing levels of steroids induced by treatments with exogenous hormones.This revealed that in a number of the early experiments the hormonal conditions which had been tested were completely outside the physi- ological range (plasma levels of steroids being several order of magni- tude above physiological levels after the injections) and a reinterpre- tation of the results was thus needed.

The importance of toxins and other phanuacologically active com­ pounds obtained from marine animals cannot be emphasized enough. The use of these chemicals for defense or attack of other life fonus are of interest in themselves; however, they are of great importance in our understanding of their mechanisms of action in view of possible application in the defense of man (no doubt a predator) and in biol­ ogy and medicine. The toxin of the flat fish Pardachirus presented in some of the papers of this book is an example of a defense mechanism based on secretion of a toxin that could possibly be extended to being used to defend man himself from sharks, the marine predators par ex­ cellence. August, 1984 J. ZADUNAISKY Preface The study of toxins, drugs, and pollutants in the marine environment, and their impact on human life existed already in Babylon and Assyria, Egypt, Persia, India, China, Japan, Greece, Rome and South America. Nevertheless, less is known about ethnic marine biology than about ethnobotany. Only recently however, have active biotoxins been used as molecular probes in neuropharmacology, offering intriguing new insights into nervous activity and muscular functions. It is clear from the presentations at this meeting that much remains to be done, and certainly new, more pharmacologically oriented find­ ings lie ahead.

This volume is one of those published from the proceedings of the invited lectures to the First International Congress of Comparative Physiology and Biochemistry I organized at Liege (Belgium) in August 1984 under the auspices of the Section of Comparative Physiology and Biochemistry of the International Union of Biological Sciences. In a general foreword to these different volumes, it seems to me appropriate to consider briefly what may be the comparative approach. Living organisms, beyond the diversity of their morphological forms, have evolved a widespread range of basic solutions to cope with the different problems, both organismal and environmental with which they are faced. Soon after the turn of the century, some biologists realized that these solutions can be best comprehended in the frame­ work of a comparative approach integrating results of physiological and biochemical studies done at the organismic, cellular and molecular levels. The development of this approach amongst both physiologists and biochemists remained, however, extremely slow until recently.

The idea of Professors Bolis and Gilles to gather together for a 3 days' meeting in the splendid environment of Crans-Montana in Switzerland a limited number of people around the subject of calcium and calcium bind­ ing proteins seemed at first particularly attractive, and when they asked me to take charge of the scientific organization of the symposium, I accepted with enthusiasm. It rapidly became clear that the major problem would be the selection of the topics, since it was impossible to cover completely and in depth such a broad and dynamic area of research. In our view, one imperative was to associate as intimately as possible the structural and the functional aspects of the areas covered. Apart from one whole day focused on the fascinating roles played by calmodulin in cellular activities, the other sessions were devoted to calmodulin-related calcium binding proteins in muscle and non­ muscle tissues and to some selected biological systems such as mitochondria, secretory cells or sarcoplasmic reticulum in which calcium also plays a crucial role. The presentations were made by leading investigators in their field. Some of them do not, however, appear in the present volume, for which there are two reasons: first, some of the contributions were somewhat outside the scope of the book; second, three speakers, for valid reasons, simply found no opportunity to write a manuscript in the allotted time.

Advances in Compararative and Environmental Physiology helps biologists, physiologists, and biochemists keep track of the extensive literature in the field. Providing comprehensive, integrated reviews and sound, critical, and provocative summaries, this series is a must for all active researchers in environmental and comparative physiology. Cellular volume and osmolality in animals is a well studied topic and this specific volume in the series provides the reader with a thorough grounding in this area of physiology. Consisting of two parts, the text discusses osmolality and volume control in terms of both inorganic and organic ions which as a result gives an excellent overview to those working and interested in this field.