An analysis of the interactions between pelagic food web processes and element cycling in lakes. While some findings are examined in terms of classical concepts from the ecological theory of predator-prey systems, special emphasis is placed on exploring how stoichiometric relationships between primary producers and herbivores influence the stability and persistence of planktonic food webs. The author develops simple dynamic models of the cycling of mineral nutrients through plankton algae and grazers, and then goes on to explore them both analytically and numerically. The results thus obtained are of great interest to both theoretical and experimental ecologists. Moreover, the models themselves are of immense practical use in the area of lake management.

Proceedings of the NATO Advanced Research Workshop, Castéra-Verduzan, France, June 1-5, 1987

This Volume belongs to a series on Oceanography. It is designed so that it can be read on its own, or used as a supplement in oceanogrphy courses. After a brief introduction to sea-floor sediments, the book shows how the activities of marine organisms cycle nutrients and other dissolved constituents within the oceans, and influence the rates at which both solid and dissolved material is removed to sediments. It goes on to review the carbonate system and shows how sediments that come from continental areas may be transported to the deep sea, explores what sea-floor sediments have taught us about the history of the oceans, and describes the biological and chemical processes that continue long after sediments have been deposited on the deep sea-floor. * Covers the basics on the occurrence, distribution, and cycling of chemical elements in the ocean * Features full-color photographs and beautiful illustrations throughout * Reader-friendly layout, writing, and graphics * Pedagogy includes chapter summaries, chapter questions with answers and comments at the end of the book; highlighted key terms; and boxed topics and explanations * Can be used alone, as a supplement, or in combination with other Open University titles in oceanography

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.

Nitrogen in the Marine Environment provides information pertinent to the many aspects of the nitrogen cycle. This book presents the advances in ocean productivity research, with emphasis on the role of microbes in nitrogen transformations with excursions to higher trophic levels. Organized into 24 chapters, this book begins with an overview of the abundance and distribution of the various forms of nitrogen in a number of estuaries. This text then provides a comparison of the nitrogen cycling of various ecosystems within the marine environment. Other chapters consider chemical distributions and methodology as an aid to those entering the field. This book discusses as well the enzymology of the initial steps of inorganic nitrogen assimilation. The final chapter deals with the philosophy and application of modeling as an investigative method in basic research on nitrogen dynamics in coastal and open-ocean marine environments. This book is a valuable resource for plant biochemists, microbiologists, aquatic ecologists, and bacteriologists.

It is a well-known fact that eutrophication of coastal waters causes significant changes in the species composition of the primary producers. Usually a shift from an ecosystem dominated by sea grasses or large brown algae to an ecosystem dominated by fast-growing green algae or phytoplankton is observed. While this shift has been documented in a number of research papers and books, the consequences of this shift are less well known. This book focuses on the consequences of such changes for nutrient cycling. The aim is to investigate how different types of primary producers influence nutrient cycling in coastal marine waters, and how nutrient cycling changes qualitatively and quantitatively as a consequence of the changes in the primary producer community caused by eutrophication. The various chapters address specific ecological processes such as grazing, decomposition, burial and export of biomass from the ecosystem. The book is intended for researchers and professionals working in the field of coastal marine ecology and estuarine ecology and for advanced students in this field.