Bookreviews

The Sea Floor: An Introduction to Marine Geology, by E . Seibold & W . H . Berger . Springer-Verlag, Berlin, 1982 . 288 pp ., 206 figs . VII . Price: DM 46,- (soft cover) . Professor Eugen Seibold's classic work 'Der Meeresboden', has now been published in an English version through cooperation with Wolfgang Berger, from Scripps Institution of Oceanography . The authors present a comprehensive survey of data related to sea floor morphology and composition, structural origin and evolution, benthic life and climatic imprint, and ocean floor resources . They endeavour to keep the book readable for those without formal training in the natural sciences, and in the reviewer's opinion, they have succeeded, thanks partly to a lucid organization of the subjects . The first two chapters present a short but rather complete outline of the main morphological elements of ocean basins and ocean margins, including a survey of the major endogenic and exogenic processes which contribute to their shaping . Sea floor sediment composition is mainly dealt with in chapters 3 (sources and composition of marine sediments) and 8 (patterns of deep sea sedimentation) . Some basic elements of mineralogy, petrography and geochemistry are added in the appendix . Effects of waves and currents and sea level changes are discussed in chapters 4 and 5, respectively . Due attention is paid to recent concepts derived from seismic stratigraphy and to the relation between global sea level changes and changes in spreading rate at the mid-ocean ridges . There is a Hydrobiologia 101, 255-258 (1983) . © Dr W . Junk Publishers, The Hague . Printed in The Netherlands .

special subchapter devoted to the author's concern for the fate of Venice . Chapter 6 presents the distribution and activity of benthic life, of which some major groups are illustrated in the appendix . The attractive subject dealing with the imprint of climatic zonation on marine sediments, both modern and ancient, is included in chapters 7 and 9 . Attention is focused on the possibilities of paleodepth determination through reconstruction of the carbonate compensation depth . The final chapter presents a very concise review of marine petroleum resources, raw materials from the shelves and deep sea deposits of heavy metals. A list of 169 major books and symposia forms a useful source for further reading . However, one might regret the absence of a bibliographical list of the references cited in the text . This introductory textbook is written in a very direct style . The reader's curiosity is often anticipated and his interest stimulated by pertinent questions on the right points, when fundamental problems are approached . In a few cases, simplifications required by conciseness and readability might induce some eyebrow raising, but as far as the reviewer can judge, acceptable limits of exactitude are not trespassed . Many concepts are illustrated by quality figures, diagrams and maps, usually derived from leading books and symposia . In a couple of figures, units or legend elements got lost, possibly during the transfer process, but these are minor inconveniences . A further pleasant aspect of this book is also found in the frequent references to the historical aspects in the development of knowledge about the

2 56 sea floor . In a field where scientists had to digest dramatic revolutions in the way of thinking within a few years' time, allusions to the human element make attractive reading . In a portrait gallery of some founders of marine geology, a pipe-smoking Wegener neighbours pipe-smoking Bourcart (still stating in 1959 : `1'idee de Wegener que l'Atlantique etait du a une fente, s'elargissant de plus en plus au cours des temps geologiques, semble aujourd'hui bien abandonnee' . . . in La Terre, Encyclopedie La Pleiade) and a (pipeless) Harry Hess, who promoted a sea floor spreading hypothesis close to present day views as early as 1960 . Jean-Pierre Henriet

Marine Mesocosms : Biological and Chemical Research in Experimental Ecosystems, G . D . Grice & M . R . Reeve (eds .) . Springer-Verlag, Berlin, 1982 . 430 pp ., 136 figs . Price : cloth DM 108,- ( approx . U S $50 .30) . Large-scale enclosures of natural water bodies have recently become an increasingly important tool in marine ecological research . The word `mesocosm' illustrates their intermediary position between the highly complex, constantly moving open water and the isolated, simplified laboratory experiment . `Marine Mesocosms : Biological and Chemical Research in Experimental Ecosystems', presents 30 papers offering an overview of the results obtained with mesocosm experiments . Special emphasis is placed on the relation between events in enclosures and in the natural environment, as well as on the integration and comparison of data obtained in different experimental systems . Most of the papers present original work with enclosures, but the book also contains an historical overview of the enclosure approach, three reviews of results obtained in the fields of marine plankton, larval fish and chemistry, and three papers that critically assess the current status and the possible future of mesocosm studies . By virtue of its design, this book is a thorough exploration of the possibilities and limitations of the enclosure approach in a broad range of marine research topics . Furthermore, it gives an easy and

complete access to older literature in . this field . Therefore it is likely to become a reference work for anyone working with enclosure experiments or planning to do so . However, a serious drawback of a book centered around a particular experimental approach is that the scientific results in the original papers tend to serve merely as illustrations of the method . In this book important results are presented on subjects as unrelated as the cycles of natural radionuclides and the population biology of a Larvacean . Much of their scientific importance an sich is lost in the context of the book, and researchers interested in zooplankton, phytoplankton, nutrient cycles, sediment-water interactions, oil pollution, heavy metal pollution, geochemical processes, fish biology, etc. all will find some interesting results, hidden between more or less unrelated papers of authors who happened to sample in enclosures of the same size range . P . Herman

The Geological Evolution of the River Nile, by Rushdi Said . Springer-Verlag, Berlin, 1981 . 151 pp. Price : US $68 .90 . The preface of this book admirably summarises its contents : a description is offered of the geological history of the River Nile since, in late Miocene times, it first excavated its course on the Egyptian plateaus . Because the Mediterranean Sea, at that time, was desiccating, and shrinking back to a reduced-size brine-pool, the river cut down very deeply into the surface of the earth, forming a canyon that was not only deeper, but also longer than the Grand Canyon of Arizona . As the Mediterranean started filling again during the early Cenozoicum, it advanced into the canyon, that eventually disappeared under the successive deposits of five rivers, that waxed and waned in succession of each other and, although flowing in the main valley, may have had very different headwaters and hydrological regimes . The modern Nile or Neonile, which is one of the humbler members of the Nile family, has started to flow for not more than 120 000 years, but its flow was arrested on several occasions - the most recent one not more than, say, 20 000 years ago . The information presented here is doubtlessly of

2 57 great interest to limnologists, who may not wish to use, in the first place, its great geological detail, but rather its hydrological - hence limnological and biogeographical- implications . However, the main value of this work, which is likely to make it a heavily cited source-book on the Nile, lies in its review character . It describes the various settings and deposits, and sequences in a very meticulous way, and any further research on the headwaters of the various Niles in the Sudan and elsewhere will have to cross-reference to it . There is an appendix, written by F . P . Bentz and J . B . Hughes, presenting recent reflection seismic evidence of the late Miocene Nile canyon . In addition to numerous illustrations given in the text, the book ends with four large fold-out geological maps of the Nile Valley . H . J . Dumont

Vicariance Biogeography: A Critique, Gareth Nelson & Donn E . Rosen (eds .) . Symposium of the Systematics Discussion Group of the American Museum of Natural History, May 2-4, 1979 . Columbia University Press, New York, 1981 . 593 pp . Price: $35 .00 . Only those who have been living on a remote island (one in the Pacific should do, if it is one that drifted there by the Palaeocene, so that the news could not have reached by dispersal), are not likely aware of what has been going on in the world of biogeography over the past 10 years or so . Charles Darwin has become a kind of a public enemy, and his followers heretics, wanted dead or alive . Dispersalim has become a dirty word . Vicariance biogeography, panbiogeography and phylogenetic biogeography - the latter marking the appearance of Hennigian cladistics on the scene as a method in biogeographical research - are the new truth . Leon Croizat, the long unrecognised and ostracized father of the new biogeography and writer of many bulky volumes, has been promoted almost to pontifical status by the restless efforts of two curators of the American Museum of Natural History in New York, Gareth Nelson and Donn . E . Rosen . The battle between dispersialists and vicariantists, created and fought in the pages of the Journal of Systemicatical Zoology (unfortunately not open to all,

since the single page charge of this journal exceeds the price of the book under review!), has been at times so violent and personal, that one prediction about it could hardly be falsified : this could not possibly continue much longer . Nelson and Rosen may have had this in mind, at least partly, when organising the Symposium that lead to this book . Although several dispersalists declined the offer to speak at the meeting (but they were old and established people, with nothing to gain and a lot to lose from such a confrontation), a wide array of contributors, representing different lines of thinking, was brought together . Evidently, and as the reader will easily be able to find out for himself, biogeography is a science conducted mainly by Americans, with the rare exception of the odd Western European or Israeli . Apart from this minor detail, however, Udvardy is allowed to mildly defend some merits of dispersalism (with the important conclusion that vicariance biogeography differs only in its way of interpreting results - not by methods), while Simberloff et al. try to introduce the rigor of statistics into the debate (but the conclusion can be no better than the data to depart from) . After Brundin's attempt to intermarry Croizat's ideas with the schemes of Willi Hennig, several contributions deal with case studies (Carabid beetles, land-snails, plants of the pacific), in which pros and cons of the two major competing (?) theories of today are evaluated - Vicariance of course being the winner . Hallam's contribution is a very useful one : it discusses plate-tectonics, but also the fall and rise in sea levels and climatic fluctuations (of course, we know best of the latter factors during the Pleistocene, but did they not matter beforehand as well?) The possibility of a lost continent, Pacifica, is a much controversal subject (Nur & Ben-Avraham), and will perhaps appeal less to European than to American readers . For those interested in provocative formulations, the synthesis by Leon Croizat himself is a must . Written in his usual verbose, but beautiful English prose, Croizat vigorously attacks the Darwinian fortress once again : `the line is now sharply and finally drawn : either the Darwinians burry me, or I them' (p . 517) . Nelson is given the honour of concluding this volume by a summary, containing a list of 35 pseudo-syllogisms distilled from the various contributions, and likely to raise debate . There is

258 none that refers to Croizat's paper, but I might add one (36), that I think reflects well the spirit of the militant vicariantist of today : Darwin was not a genius, therefore his theories are wrong . In passing, it may be useful to deplore that limnologists will not find any reference to the specific biogeographical constraints and problems posed by life in a watery environment . Further, a lot of wisdom is being presented on evolution, speciation, and 'form-making', but the advanced ideas on microevolution, its genetic and even molecular basis, as known today, are totally ignored . This volume is inexpensive and therefore may sell

well . It is not without significance, and therefore, it can be recommended to a wide readership . Its significance is not, however, in the novelty of facts or theories discussed, but in the step taken towards the extinction of the straw fire lighted by some enthusiastic angry biogeographers a decade or so ago . Croizat and his writings (which, in fact, only emphasize another strategy of nature in its accomplishment of diversity, admittedly one that Charles Darwin had grossly overseen) have become fashionable, and Nelson and Rosen are now part of the establishment . H . J . Dumont