This book aims to serve as a centralized reference document for students and researchers interested in aspects of marine nitrogen fixation. Although nitrogen is a critical element in both terrestrial and aquatic productivity, and nitrogen fixation is a key process that balances losses due to denitrification in both environments, most resources on the subject focuses on the biochemistry and microbiology of such processes and the organisms involved in the terrestrial environment on symbiosis in terrestrial systems, or on largely ecological aspects in the marine environment. This book is intended to provide an overview of N2 fixation research for marine researchers, while providing a reference on marine research for researchers in other fields, including terrestrial N2 fixation. This book bridges this knowledge gap for both specialists and non-experts, and provides an in-depth overview of the important aspects of nitrogen fixation as it relates to the marine environment. This resource will be useful for researchers in the specialized field, but also useful for scientists in other disciplines who are interested in the topic. It would provide a possible text for upper division classes or graduate seminars.

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.

Planktonic marine cyanobacteria are abundant and significant in the biogeochemistry of the sea. This volume focuses on the filamentous cyanobacteria, particularly those in the genus Trichodesmium which are common in tropical and subtropical seas. A portion of this book also concerns bloom-forming cyanobacteria in the Baltic Sea area. Filamentous cyanobacteria are important as primary producers and for the fixation of atmospheric nitrogen and thus are significant in global cycling of both of these elements. In recent years, through the application of new techniques and intensive multi-disciplinary research programs, progress has been made in understanding both the biology of these cyanobacteria and their place in the marine food web. A broad range of topics is covered in this book, ranging from molecular biology, physiology, ultrastructure, enzyme localization, toxicology, remote sensing, buoyancy, herbivory and the ecology of these organisms in the marine food web. This volume is an outgrowth of a NATO-sponsored meeting held in May 1991 in Bamberg, Germany, and represents the latest synthesis on these marine phytoplankters.

Marine biological science is now studied at the molecular level and although research scientists depend on information gained using molecular techniques, there is no book explaining the philosophy of this approach. Molecular Approaches to the Study of the Ocean introduces the reasons why molecular technology is such a powerful tool in the study of the oceans, describing the types of techniques that can be used, why they are useful and gives examples of their application. Molecular biological techniques allow phylogenetic relationships to be explored in a manner that no macroscopic method can; although the book deals with organisms near the base of the marine food web, the ideas can be used in studies of macroorganisms as well as those in freshwater environments.

This book provides essential information regarding the dynamics and rate processes of nitrogenous compounds in the sea. Topics discussed include characteristics and behavior of nitrogen at the atomic, molecular, and isotopic levels; elemental rate processes and physico-chemical and biological factors; the dynamics of nitrogen in several representative marine ecosystems; and current progress in isotope marine biogeochemistry. The book emphasizes the distribution and variation of nitrogen isotopes, which can provide a novel approach to understanding nitrogen metabolisms occurring in marine ecosystems. Nitrogen in the Sea: Forms, Abundances, and Rate Processes should be considered an indispensable reference tool for researchers and post-graduate students interested in the nitrogen cycle in aquatic ecosystems

Our desire to understand the global carbon cycle and its link to the climate system represents a huge challenge. These overarching questions have driven a great deal of scientific endeavour in recent years: What are the basic oceanic mechanisms which control the oceanic carbon reservoirs and the partitioning of carbon between ocean and atmosphere? How do these mechanisms depend on the state of the climate system and how does the carbon cycle feed back on climate? What is the current rate at which fossil fuel carbon dioxide is absorbed by the oceans and how might this change in the future? To begin to answer these questions we must first understand the distribution of carbon in the ocean, its partitioning between different ocean reservoirs (the "solubility" and "biological" pumps of carbon), the mechanisms controlling these reservoirs, and the relationship of the significant physical and biological processes to the physical environment. The recent surveys from the JGOFS and WOCE (Joint Global Ocean Flux Study and World Ocean Circulation Ex periment) programs have given us a first truly global survey of the physical and biogeochemical properties of the ocean. These new, high quality data provide the opportunity to better quantify the present oceans reservoirs of carbon and the changes due to fossil fuel burning. In addition, diverse process studies and time-series observations have clearly revealed the complexity of interactions between nutrient cycles, ecosystems, the carbon-cycle and the physical envi ronment.

Many oceans are currently undergoing rapid changes in environmental conditions such as warming temperature, acidic water condition, coastal hypoxia, etc. These changes could lead to dramatic changes in the biology and ecology of phytoplankton and consequently impact the entire marine ecosystems and global biogeochemical cycles. Marine phytoplankton can be an important indicator for the changes in marine environments and ecosystems since they are major primary producers that consolidate solar energy into various organic matter transferred to marine ecosystems throughout the food-webs. Similarly, the N2 fixers (diazotrophs) are also vulnerable to changing environmental conditions. It has been found that the polar regions can be introduced to diazotrophic activity under warming conditions and the increased N availability can lead to elevated primary productivity. Considering the fundamental roles of phytoplankton in marine ecosystems and global biogeochemical cycles, it is important to understand phytoplankton ecology and N2 fixation as a potential N source in various oceans. This Special Issue provides ecological and biogeochemical baselines in a wide range of geographic study regions for the changes in marine environments and ecosystems driven by global climate changes.