Experts in the field offer the first comprehensive review of the tectonics and magmatism of backarc basins, covering their initial rift stage to mature spreading. Complete with numerous illustrations, each of the twelve chapters focuses on a young, active backarc basin of the circum-Pacific-where volcano-tectonic processes are best studied because of their activity. Key themes in this volume include volcano-tectonics setting; cause and location; rift magmas; and hydrothermal activity. Researchers also present models of the dynamic processes occurring in backarc basins.

Solid-solution equilibria of marine evaporites are important in a wide range of science and technology. However, the data had not yet been summarized in a form that is at the same time comprehensive and permits to understand how the quinary seawater system builds up from its bounding systems. Thus the goal of the present volume is at the same time scientific and educational. The understanding of solid-solution equilibria of the various systems with respect to dissolution, precipitation and transformation of solids, their application to the evolution of brines, and a fast access to data is a necessary requirement for any modelling, especially in Geoscience. Another goal is to show the avail ability of data. Unfortunately, though solubility data are numereous there are substantial gaps, especially with respect to high temperatures. But also up to about 100 0 C data are missing for some of the systems so that they cannot be described entirely. Based on the present volume further work on the solubili ties of the minerals of marine evaporites may be promoted. The data have been viewed and collected over several years by the first author. The second author entered the preparation of the volume when it was realized that besides graphics and tables a fast access to data was required. Although both authors are responsible for the whole volume, responsibility is weighted somewhat differently for the various parts."

Seafloor investigation has long been a feature of not only seismology but also of acoustics. Indeed it was acoustics that produced depth sounders, giving us the first capability of producing both global and local maps of the seafloor. Subsequently, better instrumentation and techniques led to a clearer, more quantitative picture of the seabed itself, which stimulated new hypotheses such as seafloor spreading through the availability of more reliable data on sediment thickness over ocean basins and other bottom features. Geologists and geophysicists have used both acoustic and seismic methods to study the seabed by considering the propagation of signals arising from both natural seismic events and man-made impulsive sources. Although significant advances have been made in instrumentation, such as long towed geophysical arrays, ai r guns and ocean bot tom seismometers, the pic ture of the seafloor is still far from complete. Underwater acoustics concerns itself today with the phenomena of propagation and noise at frequencies and ranges that require an understanding of acoustic interaction at both of its boundaries, the sea surface and seafloor, over depths ranging from tens to thousands of meters. Much of the earlier higher frequency (>1 kHz) work included the characterization of the seafloor in regimes of reflection coefficients which were empirically derived from surveys. The results of these studies met with only limited success, confined as they were to those areas where survey data existed and lacking a physical understanding of the processes of reflection and scattering.

Opening Speech of the ICEDIVE 84 Conference by His Royal Highness Prince Bertil of Sweden I am very pleased to be invited to open the International Conference ICEDIVE 84, dealing with medical and technical problems of diving and related underwater activities in arctic conditions. Until recent times, the arctic was considered astrange and remote area of minor importance. However, in a world with diminishing natural resources, arctic areas have become a region of global importance because of their enormous resources and strategie position. Certain experts believe that more than 50% of oil reserves are "sleeping" in these northern areas which are cold, harsh and hostile to man. Operations in arctic areas are extremely difficult, expensive, and demand high levels of technical, scientific and physiological achievement. One should recall for example, that Alaskan oil investment onIy became economically viable after the 1973-1974 price explosion. Recent political/military troubles in the Gulf have increased interest in the development of polar resources. This conference is unique as it is the first time that medical and technical specialists interested in the problem of diving in arctic conditions have met in an international forum. Development of the arctic resources is a matter of international urgency, and it pleases me that scientists from the USA, Canada, the USSR, Australia and Europe have gathered here in Stockholm to present their experience and to discuss problems in this field.

This book grew out of lectures on geophysical fluid dynamics delivered over many years at the Moscow Institute of Physics and Technology by the author (and, with regard to some parts of the book, by his colleagues). During these lectures the students were advised to read many books, and sometimes individual articles, in order to acquaint themselves with the necessary material, since there was no single book available which provided a sufficiently complete and systematic account (except, perhaps, the volumes on Hydrophysics of the Ocean, Hydrodynamics of the Ocean, and Geodynamics in the ten-volume Oceanology series published by Nauka Press in 1978-1979; these refer, however, specifically to the ocean, and anyway they are much too massive to be convenient for study by students). As far as we know, no text corresponding to our understanding of geophysical fluid dynamics has as yet been published outside the Soviet Union. The present book is designed to fill this gap. Since it is customary to write the preface after the entire book has been completed, the author has an opportunity there to raise some points of possible criticism by the reviewers and readers. First of all, note that this work presents the theoretical fundamentals of geophysical fluid dynamics, and that observational and experimental data (which in the natural sciences are always very copious) are referred to only rarely and briefly.

There is now an awareness within the industry, particularly as oil companies direct considerable resources towards developing diverless production systems, that a fully integrated approach to equipment design and intervention is necessary to achieve an acceptable system. The requirement for an integrated approach to equipment design and intervention is applicable not only to diverless depths but to all subsea structures, equipment and intervention techniques in whatever depth. Fortunately the inherent dexterity of the diver does not impact so severely on design as other intervention techniques. However the benefits of an integrated approach are still applicable and the use of such simple "diver aids" as cutting guides and subsea markings installed prior to the installation of jackets and subsea equipment can have a significant impact on the cost of intervention. This paper examines the requirements and limitations in designing subsea equipment for Remotely Operated Vehicle (ROV) intervention. For the oil company embarking on the development of a diverless production system, be it totally diverless because of the envisaged water depth or primarily diverless with the possibility of diver back up, the intervention techniques adopted will strongly influence the final system design. The necessity to undertake an extensive development programme to produce the optimum intervention system is very costly, requires long lead times and comprehensive testing particularly where novel solutions are adopted. It is a daunting prospect for even the most progressive of oil companies.

When, in 1966, the Gennan Research Society directed the attention of oceanographers in the Federal Republic of Ger many to problems of marine pollution, I was not enthusiastic. Emphasis on this problem area meant that other important research plans had to be postponed. But the lectures at the Third International Oceanographic Congress, September 1970, in Tokyo, and at the FAO Conference on Marine Pollution and its Effects on Living Resources and Fishing, December 1970, in Rome, convinced me that research on problems of marine pollution is a social obligation, and that the oceanographer has to take a stand. I issued public warnings about the continuing use of pesticides and had to defend myself against protests by the fishing industry and many colleagues who were, in Novem ber 1970, unaware of the extent of the threat. Thus, I was required by my profession to acquire an overview of the prob lems of ocean pollution. In 1971 I only needed to familiarize myself with some one hundred bibliographical items. In the interim, the flood of data has risen dramatically, and in the year 1975, no fewer than 868 publications under the heading of "Marine Pollution" were reported (Table 1). It is, therefore, more and more diffi cult to distinguish new results of scientific research from the many repetitions and variations, and I fear that from year to year my efforts to illustrate the actual status of the problem at a given moment will be subject to more gaps."

The monograph presented to foreign readers has been prepared by the famous Soviet investigators of processes of geochemistry and sedimentation in the Mediterranean Sea. For more than 20 years E.M. Emelyanov has examined the recent sedimentation of the Mediterranean Sea and K.M. Shimkus has studied the Quaternary and the earlier sedi mentation of the area. The authors, scientific workers from the P.P. Shirshov Institute of Oceanology, USSR Academy of Sciences (Atlantic and Southern Depart ments), took part not only in numerous cruises on oceanographic vessels of the USSR, but in the study of cores of the deep-sea drilling on R/V "Glomar Challenger." A great number of scientific papers and some books devoted to the processes of sedimentation and geochemistry of the Mediterranean Sea were written by them. Although the scientific interests of the authors are not only limited to these questions, I should like to emphasise these aspects of their scientific activity when introducing this book. The Mediterranean Sea is a suitable natural laboratory for solving a number of principal problems of marine sedimentation and lithogenesis."

The impetus for the conference held at Bombannes, France in May, 1982 arose out of a Scientific Committee on Oceanic Research (SCOR) Working Group on "Mathematical Models in Biological Oceanography." This group was chaired by K.H. Mann and held two meetings in 1977 and 1979. At both meetings it was felt that, although reductionist modelling of marine ecosystems had achieved some successes, the future progress lay in the development of holistic ecosystem models. The members of the group (K.H. Mann, T. Platt, J.M. Colebrook, D.F. Smith, M.J.R. Fasham, J. Field, G. Radach, R.E. Ulanowicz and F. Wulff) produced a critical review of reductionist and holistic models which was published by the Unesco Press (Platt, Mann and Ulanowicz, 1981). One of the conclusions of this review was that, whether holistic or reductionist models are preferred, it is critically important to increase the scientific effort in the measurement of physiological rates for the computation of ecological fluxes. The Working Group therefore recommended that an international meeting should be organized which would attempt to bring together theoretical ecologists and biological oceanographers to assess the present and future capability for measuring ecological fluxes and incorporating these data into models. An approach was made to the Marine Sciences Panel of the NATO Science Committee who expressed an interest in funding such a meeting. They awarded a planning grant and a planning group was formed consisting of M.J.R. Fasham, M.V. Angel, T. Platt, R.E.

Primary productivity in the sea accounts for 30% of the total global annual production. Holistic understanding of the factors determining marine productivity requires detailed knowl edge of algal physiology and of hydrodynamics. Traditionally studies of aquatic primary productivity have heen conducted hy workers in two major schools: experimental laboratory biology, and empirical field ecology. Here an attempt was made .to hring together people from both schools to share information and con cepts; each author was charged with reviewing his field of exoer tise. The scope of the Symposium is broad, which we feel is its strength. We gratefully acknowledge financial support from the Depart ment of Energy, the United States Environmental Protection Agency, the National Oceanic and Atmospheric Administration, including the NMFS Northeast Fisheries Center and the MESA New York Bight Project. Thanks are due to Mrs. Margaret Dienes, with out whose editorial skills this volume could not have been pro duced, and to Mrs. Helen Kondratuk as Symposium Coordinator. Finally, we wish to record our indebtedness to Dr. Alexander Hollaender for his tireless efforts and valuable advice in sup porting all aspects of this Symposium."

The oceans are vast with t, Yo-thirds of our planet being covered by a thick layer of water, the depth of which can be likened to flying above the earth's surface at an altitude of 30,000 feet (9,800 m). Good to play in, essential for life but deadly to breathe, water is important to all organisms on the planet, and the oceans form its major reservoir containing approximately 97 per cent of all freely available surface water. In spite of this obvious importance mankind has still much to learn about this ocean environment. Study of the oceans has grown enormously since the eighteenth- and nineteenth-century voyages of scientific discovery, expanding greatly in the period post 1945. One of the subjects that has blossomed in this period has been the study of the ocean's surface, and in particular the study of sea level and related sea-surface changes. Indeed this topic may even be termed 'popular', as reflected in the growing number of general geo morphology, physical geology and oceanography texts which now give space to the subject."

Sea ice is a major component of polar environments, especially in the Arctic where it covers the entire Arctic Ocean throughout most of the year. However, in the context of climate change, the Arctic sea ice cover has been declining significantly over the last decades, either in terms of its concentration or thickness. The sea ice cover evolution and climate change are strongly coupled through the albedo positive feedback, thus possibly explaining the Arctic amplification of climate warming. In addition to thermodynamics, sea ice kinematics (drift, deformation) appears as an essential factor in the evolution of the ice cover through a reduction of the average ice age (and consequently of the cover's thickness), or ice export out of the Arctic. This is a first motivation for a better understanding of the kinematical and mechanical processes of sea ice. A more upstream, theoretical motivation is a better understanding of the brittle deformation of geophysical objects across a wide range of scales. Indeed, owing to its very strong kinematics, compared e.g. to the Earth s crust, an unrivaled kinematical data set is available for sea ice from in situ (e.g. drifting buoys) or satellite observations. Here, we review the recent advances in the understanding of sea ice drift, deformation and fracturing obtained from these data. We focus particularly on the scaling properties in time and scale that characterize these processes, and we emphasize the analogies that can be drawn from the deformation of the Earth s crust. These scaling properties, which are the signature of long-range elastic interactions within the cover, constrain future developments in the modeling of sea ice mechanics. We also show that kinematical and rheological variables such as average velocity, average strain-rate or strength have significantly changed over the last decades, accompanying and actually accelerating the Arctic sea ice decline.

Deep-sea manganese nodules, once an obscure scientific curios ity, have, in the brief span of two decades, become a potential mineral resource of major importance. Nodules that cover the sea floor of the tropical North Pacific may represent a vast ore de posit of manganese, nickel, cobalt, and copper. Modern technology has apparently surmounted the incredible problem of recovering nodules in water depths of 5000 meters and the extraction of metals from the complex chemical nodule matrix is a reality. Both the recovery and the extraction appear to be economically feasible. Exploitation of this resource is, however, hindered more by the lack of an international legal structure allowing for recognition of mining sites and exploitation rights, than by any other factor. Often, when a mineral deposit becomes identified as an ex ploitable resource, scientific study burgeons. Interest in the nature and genesis of the deposit increases and much is learned from large scale exploration. The case is self evident for petrol eum and ore deposits on land. The study of manganese nodules is just now entering this phase. What was the esoteric field of a few scientists has become the subject of active exploration and research by most of the industrialized nations. Unfortunately for our general understanding of manganese nodules, exploration results remain largely proprietary. However, scientific study has greatly increased and the results are becoming widely available."

The era of the exploration of the World Ocean is not yet over: some areas still lack an adequate number of observations. The relationships between the physical, chemical and biological processes, which sustain the life on this planet, are not yet fully understood. In short, knowledge of the oceans is still far from satisfactory. This book covers an important period in the study of one of the last investigated areas of the World Ocean: the Ross Sea, Antarctica. During the 1990s, long-term experiments were conducted in this area as part of the Climatic Long-term Interaction for the Mass balance in Antarctica (CLIMA) project of the Italian National Programme for Antarctic Research (PNRA), providing a wealth of oceanographic information. This book is an outcome of the CLIMA field obser vations and international collaborations with the most important programmes in the Ross Sea-Southern Ocean area. It contributes to the st ldies of the spatial and temporal variability of Ross Sea water masses and circulation and their relation ship with the Southern Ocean circulation. A comprehensive review of historical data is offered, and new data sets are analysed. The studies presented in this book show that much progress has been achieved during the last decade, but large gaps in our understanding of the physical processes in the Ross Sea are still to be filled. However, these studies contribute significantly to the investigation of some specific aspects regarding the circula tion of the main water masses."

My work Geochemistry oj organic matter in the ocean first appeared in Russian in 1978. Since then much progress has been made in the exploration of various forms of organic matter in the ocean: dissolved, colloidal, organic matter sus pended in particles and that contained in bottom sediments and in interstitial waters. The appropriate evidence is found in hundreds of articles and several re view works, such as Andersen (1977), Biogeochimie de [a matiere organique a ['interjace eau-sedimentmarine (1980), Duursma and Dawson (1981). A great amount of new information has been obtained in the Soviet Union's scientific institutions on the composition and distribution in natural waters and bottom sediments of organic matter and its separate components playing a crucial role in the formation of the chemical and biological structure of the ocean and its productivity, in the biogeochemistry of the elements and geochemistry of organic matter in the Earth's sedimentary cover. The areas of exploration have expanded over the past four-and-a-half years to embrace many new, little-known regions, including the Arctic seas. In contrast to the three preceeding decades, the research has been focused on investigating the existing forms, the distribution and accumulation of organic matter in near continental oceanic zones between land and sea, and in river estuaries.

vi These categories seem to represent the basic breakdown by field of present-day research in this area. Though each paper has been classified into one of these categories (for conference organization purpose), many papers overlapped two or three areas. It is also interesting to note that not only are scientific results being communicated, but the latest techniques and the state-of-the-art tools of the trade (existing and in development) are also being presented. The forty-six papers presented at this conference represent the work of seventy scientists working at universities, government laboratories, and industrial laboratories in seven different countries . We would like to thank the contributors for their efforts and especially for their promptness in providing the editors with their final manuscripts. William A. Kuperman Finn B. Jensen La Spezia, Italy July 1980 CONTENTS GEOACOUSTIC PROPERTIES OF MARINE SEDIMENTS Attenuation of Sound in Marine Sediments . * 1 J. M. Hovem Directivity and Radiation Impedance of a Transducer 15 Embedded in a Lossy Medium . ** ****** G. H. Ziehm Elastic Properties Related to Depth of Burial, Strontium Content and Age, and Diagenetic Stage in Pelagic Carbonate Sediments . . * * . * * * . 41 M. H. Manghnani, S. O. Schianger, and P. D. Milholland Application of Geophysical Methods 'and Equipment to Explore the Sea Bottom . ** ***. * 53 H. F. Weichart The Acoustic Response of Some Gas-Charged Sediments in the Northern Adriatic Sea * * * * . * * * * 73 A.

This book is a collection of all the lectures by the professors attending the 3rd "Interna tional School on Marine Chemistry" held in Ustica (Palermo, Italy, September 2000), under the auspices of the United Nations and the Italian Chemical Society. The School was organized by the University of Palermo in co-operation with the Natural Marine Reserve of Ustica Island. The Organising Committee of the School wishes to thank the University of Messina, the University of Roma "La Sapienza: ' the Italian University Consortium of Environ mental Chemistry, and the Marine Reserve of Ustica Island for their financial support to the School. This book has been printed with the financial support of the Environmental Re search Centre CIRITA of the University of Palermo. thank all the professors whose outstanding scientific contributions have The editors made it possible to publish this book. Professor Antonio Gianguzza Professor Ezio Pelizzetti Professor Silvio Sammartano Contents Part I Biogeochemical Processes at the Air-Water and Water-Sediment Interface .............................................. ."

Some 90 years ago, the first information on the occurrence of dissolved organic matter in sea water was published. For 50 years after that reve- lation, little progress was made in identifying these dissolved "yellow substances." In the 1950s and 1960s, a few chemical oceanographers identified some specific dissolved organic compounds, but few of these pioneers fully appreciated their significance in terms of biological inter- actions, metal chelation, or interactions with sedimentary material. When Mohammed Rashid began his work on marine humic compounds in the mid-1960s, he was one of only five scientists who had specifically designed their studies toward understanding the nature of these complex materials. Over the next decade, Dr. Rashid directed his research toward characterization of humic and fulvic compounds in the marine environ- ment, the influence of humic substances on the growth of marine phy- toplankton, the role of organic matter in complexing metals in sea water and marine sediments, the interaction between humic substances and clay minerals in marine environments, and the influence of organic matter on the geotechnical properties of marine sediments. As if the many papers produced from these scientific investigations were not sufficient, Dr.

Burgeoning research into marine natural products during the past two decades has in no small measure been due to an heightened and world-wide interest in the ocean, to the development of new sophisticated computer-driven instrumentation, and to major advances in separation science. Organic chemists have been fully aware that processes in living systems occur in an aqueous medium. Nevertheless, the chemists who have specialized in the study of small molecules have found it expedient to use organic rather than aqueous solvents for the isolation and manipulation of secondary metabolites. The emergence of new chromatographic techniques, the promise of rewarding results, not to mention the relevance of polar molecules to life itself, have contributed to a new awareness of the importance of organic chemistry in an aqueous medium. The first chapter in Volume 2 of Bioorganic Marine Chemistry reflects the growing interest and concern with water-soluble com pounds. Quinn, who pioneered the separation of such molecules, has contributed a review which closely links techniques with results and is based on practical experience. The second chapter, by Stonik and Elyakov, examines the vast chemical literature of the phylum Echinodermata - over one fourth of it in difficulty accessible Russian language publications. The Soviet authors evaluate the data for their suitability as chemotaxonomic markers."

In recent years there has been an increased realization that the casual disposal of wastes can lead to a deterioration in environmen tal quality with substantial impacts on society. The management of waste disposal practices must consider the various alternatives of discharging and decomposing wastes on land, in the atmosphere, and in the marine environment. Up until 1972 ocean dumping was used increasingly to dispose of sewage sludge, industrial wastes, and dredged material. In subsequent years regulations were developed to reduce and minimize ocean dumping. These regulations were prompted often by ignorance of the possible effects of waste disposal in the ocean rather than by knowledge that such ocean dumping was detrimen tal to the marine environment or to man. The relationship between waste disposal and the oceans can be viewed in either of two ways. One may want to assure that waste disposal procedures do not alter adversely the marine environment, or one may choose to utilize the ocean as a waste depository to reduce the burden placed on the con tinental ecosystem and on the atmosphere. From either perspective it is essential that there be an adequate base of technical information to assess the fate and effects of wastes introduced to the ocean. A series of original technical papers has been compiled in this book to present some of the recent results of research on industrial waste disposal in the ocean."

This book represents a compilation of papers presented at a symposium on the subject "Suspended Solids in Hater." held in Santa Barbara. California. U.S.A . on March 20. 2] and 22, 1973. The symposium was sponsored by the Office of Naval Research and was designed to bring together a group that represented the domi nant cross section of international research in this area. The idea for the conference originated as ONR recognized a potentially interesting area that, to date. had not had the benefit of a co ordinating symposium and/or a book published on the specific sub ject. In addition to the formal presentation of papers - informal open discussions followed - the symposium included two stimulating workshops. An abundance of impromptu exchange filled unscheduled periods. Many of the contributors have incorporated in their pa pers the ideas and points raised in discussions following formal presentation and at other times. The reader thus actually profits from the various discussions throughout the meeting. The two half-day workshops were directed toward the subjects of sampling and concentrating suspended materials and in situ in strumentation. I have summarized the discussions from the two workshops for the reader and have correlated the material wherever possible in an introductory chapter. I have also included intro ductory material to acquaint the newcomer with the general field."

1 2 J. H. SCHROEDER and B. H. PURSER 1 Introduction A symposium convened during the Vth International Coral Reef Congress in Papeete, Tahiti, 1985, encouraged the editors to assemble this volume of case studies by participating and, especially, by nonparticipating scientists. An attempt was made to include case studies from various regions and geological periods, carried out on various scales from regional to ultrastructural. We hope to present an overall view of reef diagenesis. Although the volume focuses on reef diagenesis, fields also to be considered are biology, paleontology, and sedimentary facies distribution, as they provide the context and, to some extent, encompass the determinants of diagenetic processes. The scope has been limited to reef diagenesis because we feel that reefs have relatively clearly defined geometries, which facilitate the evaluation of diagenetic trends and the definition of diagenetic models. On the other hand, their many different components make reefs somewhat more complex than other deposits, and this creates difficulties in deciphering diagenetic histories; the study of reefs, therefore, is not the simplest manner of solving the many problems relating to carbonate diagenesis. An additional reason for evaluating reef diagenesis is the reservoir potential of these carbonate bodies. To illustrate the point, in the recent collection of 35 case studies of carbonate reservoirs (Roehl and Choquette 1985), reefs were involved in 15. The emphasis on porosity development in many studies of the present volume is therefore not of mere academic interest.