Natural microbial habitats include various interfaces--liquid-liquid, gas-liquid, solid-liquid, and solid-gas. An interface, the boundary between two phases, has physical and chemical properties that differ from those of either phase. Bacteria, yeasts, and algae often concentrate at interfaces, and the ability of microorganisms to exploit resources in their environment may be markedly affected by the nature of the available interfaces. Included within the realm of microbial activity at interfaces are such wide-ranging topics as predator-prey relations, tooth decay, gastrointestinal tract infections, mating contact, marine fouling, adsorptive bubble processes, oil degradation, rhizosphere associations, and bacterium-clay interactions.

In this book, bacteria are treated as living colloidal systems, and the behavior of microorganisms at interfaces is analyzed on the basis of this concept. Nonspecific physical and chemical forces acting on microorganisms at interfaces are described and related to biological factors determining the distribution of and interaction between microorganisms in both aquatic and terrestrial ecosystems. The final chapter describes specific microbe-microbe, microbe-plant, and microbe-animal interfacial interactions.

Although laboratory studies of cultured microorganisms are essential in assessing their potential capabilities, an individual microbial species in a natural habitat is confronted by physical, chemical, and biological interactions rarely encountered under pure culture conditions. Interfaces are important aspects of microbial ecosystems, and this study of the influence of interfaces on natural habitats is an important and original contribution to microbial ecology.

Advances in Microbial Ecology was established by the International Committee on Microbial Ecology (ICOME) to provide a vehicle for in-depth, critical, and even provocative reviews to emphasize recent trends in the important field of microbial ecology. Advances in Microbial Ecology is now recognized as a major source of infor mation and inspiration both for practicing and for prospective microbial ecologists. Most reviews appearing in Advances have been prepared by leaders in particular areas follow ing invitations issued by the Editorial Board. Individuals are encouraged, however, to submit outlines of unsolicited contributions to any member of the Editorial Board for consideration for publication in Advances. With the publication of Volume 12 of Advances in Microbial Ecology there will be a change of Editor and the entire Editorial Board. The current Editor wishes to take this opportunity to thank the present Editorial Board, Ron Atlas, Bo Barker J~rgensen, and Gwyn Jones, as well as past members of the Board, for their assistance and encourage ment over the years. The new Editor of Advances in Microbial Ecology will be Gwyn Jones, with Bernhard Schink, Warwick F. Vincent, and David M. Ward as members of the Editorial Board. The outgoing Board wish the new Board every success in continu ing the traditions established by Martin Alexander, the founding Editor of Advances in Microbial Ecology. The topics featured in Volume 12 of Advances include some related to the meta bolic activities of bacteria; namely, bioremediation of oil spills, by R. M. Atlas and R.

This volume of Advances in Microbial Ecology marks a change in the editor ship of the series. The Editorial Board wishes to take this opportunity to express its gratitude to Martin Alexander, the founding editor and editor of the first five volumes, for his enterprise in establishing the series and in ensuring that Advances has become an outstanding focal point for the identification of new developments in the rapidly expanding field of microbial ecology. With the publication of this volume, we welcome Howard Slater to the Editorial Board. The policies of the Editorial Board remain the same as before. Most con tributions to Advances in Microbial Ecology will be solicited by the Board. However, individuals are encouraged to submit outlines of unsolicited contri butions to the Board for consideration for inclusion in the series. Advances is designed to serve an international audience and to provide critical reviews on basic and applied aspects of microbial ecology. Contributions in the present volume are predominantly concerned with the ecology of aquatic microorganisms, but encompass a variety of approaches to this area. The exception is the chapter by J. W. Doran on the role of micro organisms in the cycling of selenium. G-Y. Rhee discusses the effects of envi ronmental factors on phytoplankton growth. The factors limiting the produc tivity of freshwater microbial ecosystems are considered by H. W. Paerl."

usage of the terms substrate and substratum. A substrate (pI.: substrates) is a material utilized by microorganisms, generally as a source of energy. A substratum (pI.: substrata) is asolid surface to which a microorganism mayattach. REFERENCES (1) Marshall, K.C. 1976. Interfaces in Microbial Ecology. Cambridge, MA: Harvard University Press. (2) ZoBell, C.E. 1943. The effect of solid surfaces upon bacterial activity. J. Bacteriol. 46: 39-56. Standing, left to right: Paul Rutter, Rolf Freter, Mike Silverman, lan Robb, Hinrich Mrozek, Frank Dazzo, David Gingell Seated, left to right: Garth Jones, Stanislawa Tylewska, Staffan Kjelleberg, Ellen Rades-Rohkohl, Kevin Marshall Microbial Adhesion and Aggregation, ed. K.C. Marshall, pp. 5-19. Dahlem Konferenzen 1984. Berlin, Heidelberg, New York, Tokyo: Springer-Verlag. Mechanisms of Adhesion Group Report P.R. Rutter, Rapporteur F.B. Dazzo H. Mrozek R. Freter E. Rades-Rohkohl D. GingeIl I.D. Robb G.W. Jones M. Silverman 8. Kjelleberg 8. Tylewska K.C. Marshall INTRODUCTION The subject, Mechanisms of Microbial Attachment, has proved to be a fertile sour ce of argument between both microbiologists and physical chemists. In order to find common ground for discussion, the group endeavored to come to a consensus regarding a number of definitions pertinent to the subject. Some of these are described in the text and others will be found at the end of this report.

The publication of Volume. 10 of Advances in Microbial Ecology repre sents something of a milestone in the history of modern microbial ecol ogy. Advances in Microbial Ecology was established by the International Committee on Microbial Ecology (ICOME) to provide a vehicle for in depth, critical, and even provocative reviews to emphasize current trends in the rapidly expanding field of microbial ecology. Martin Alexander was the Founding Editor of the series and was responsible for editing the first five volumes. The next five volumes were edited by Kevin Marshall. Advances in Microbial Ecology has attained recognition as an authorita tive source of information and inspiration for practicing and prospective microbial ecologists. The Editorial Board usually invites contributions from leading microbial ecologists, but also encourages individuals to sub mit outlines of unsolicited contributions to any member of the Board for consideration for publication in Advances. Contributions to Volume 10 again cover a broad range of topics related to microbial ecology. Interactions between microorganisms are well represented with chapters on bacterium-virulent bacteriophage interactions by R. E. Lenski, on fungal communities in the decay of wood by A. D. M. Rayner and L. Boddy, on recognition in the nematode nematophagous fungus system by B. Nordbring-Hertz, and on phago trophic phytoflagellates by R. W. Sanders and K. G. Porter. Chapters with both an ecological and a biogeochemical flavor include those on atmo spheric CO and H2 by R.