Marine Nitrogen Fixation

Description

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. Foreword References Preface Acknowledgments Contents Chapter 1: Nitrogen Fixation in the Marine Environment 1.1 The Nitrogen Cycle 1.2 Terrestrial and Aquatic Environments References Chapter 2: Fundamentals of N2 Fixation 2.1 Microbiology 2.2 Nitrogen Fixation Reaction and Nitrogenases 2.3 The Biological Nitrogen Fixation Reaction 2.4 Non-structural nif Genes and Protein Assembly 2.5 Cellular Regulation of Nitrogenase 2.6 Conclusions References Chapter 3: History of Research on Marine N2 Fixation 3.1 History of Studies of Marine N2 Fixation 3.2 Process Oriented Studies: Water Column 3.3 Benthic Marine Environments 3.4 Concluding Remarks References Chapter 4: Microorganisms and Habitats 4.1 The Surface Ocean (Pelagic) Cyanobacteria Heterotrophic N2 Fixers 4.2 Oxygen Deficient Zones (ODZs) 4.3 Mesopelagic and Deep Ocean 4.4 The Benthos Microbial Mats Shallow Sediments Corals and Coral Reefs Marine Plant Communities Deep Sea Benthos 4.5 Conclusions References Chapter 5: Measurements of Organism Abundances and Activities 5.1 Introduction 5.2 Cultivation 5.3 The Acetylene Reduction Method 5.4 Isotopic Tracers: 15N 5.5 Hydrogen 5.6 Functional Gene Analysis 5.7 Stable Isotope Probing 5.8 Biogeochemical Proxies 5.9 Remote Sensing 5.10 Experimental and Observational Formats and Scales 5.11 Mathematical Models 5.12 Conclusions References Chapter 6: Factors Controlling N2 Fixation 6.1 Oxygen 6.2 Light 6.3 Temperature 6.4 Nutrients 6.5 Dissolved Organic Matter 6.6 Salinity 6.7 pH 6.8 Turbulence 6.9 Fate of Diazotrophs 6.10 Conclusions References Chapter 7: Biogeography of N2 Fixation in the Surface Ocean 7.1 Factors Controlling the Distribution of N2 Fixation Biogeography 7.2 Nutrient Limitation Geography 7.3 N2 Fixation Variables 7.4 Oligotrophic Oceans 7.5 Coastal and Upwelling Regions 7.6 Seasonality 7.7 Low O2 Waters 7.8 Estuaries and Inland Seas 7.9 High Latitudes Including the Arctic 7.10 Conclusions References Chapter 8: N2 Fixation in Ocean Basins 8.1 Nutrient Relationships, Ratios and N Cycle Feedbacks Stable Isotope Inferences The N* Parameter and N2 Fixation 8.2 Basin and Global Scale Inputs Pelagic Studies Heterotrophic N2 Fixation Inputs Benthic Studies 8.3 Conclusions References Chapter 9: Marine N2 Fixation, Global Change and the Future 9.1 Effects of Environmental Changes on Species 9.2 Large-Scale Shifts in N2 Fixation in the Global Ocean 9.3 Ocean Fertilization and Marine N2 Fixation 9.4 Marine Aquaculture, Biotechnology and N2 Fixation 9.5 Overcoming Challenges for Future N2 Fixation Research 9.6 Conclusions References Chapter 10: Summary and Conclusions 10.1 Introduction 10.2 Fundamentals 10.3 History 10.4 Microorganisms 10.5 Measurements 10.6 Factors 10.7 Biogeography 10.8 N2 Fixation in Ocean Basins 10.9 Marine N2 Fixation, Global Change and the Future 10.10 Over-Arching Questions, Controversies and Future Directions Microbiological Physiological Ecological/Biogeochemical Methodological/Technological 10.11 Closing Comments Index