Biogeochemistry

Biogeochemistry is the scientific discipline that explores the complex interactions between biological, geological, and chemical processes that control the distribution and cycling of elements within Earth's systems. It investigates how living organisms influence, and are influenced by, the chemical composition of the atmosphere, hydrosphere, and lithosphere. By studying the global cycles of essential elements like carbon, nitrogen, and phosphorus, this interdisciplinary field provides a critical framework for understanding everything from ecosystem function and nutrient availability to the planet's response to large-scale environmental change.

  1. Introduction to Biogeochemistry
    1. Defining Biogeochemistry
      1. Core Definition and Scope
        1. Intersection of Earth and Life Sciences
          1. Spatial and Temporal Scales
            1. Distinction from Geochemistry
              1. Distinction from Biochemistry
                1. Distinction from Ecology
                2. Interdisciplinary Nature
                  1. Integration of Biology
                    1. Microbiology
                      1. Ecology
                        1. Physiology
                        2. Integration of Geology
                          1. Mineralogy
                            1. Petrology
                              1. Sedimentology
                              2. Integration of Chemistry
                                1. Analytical Chemistry
                                  1. Physical Chemistry
                                    1. Environmental Chemistry
                                    2. Role of Physics
                                      1. Thermodynamics
                                        1. Fluid Dynamics
                                        2. Role of Mathematics
                                          1. Modeling and Statistics
                                            1. Mass Balance Equations
                                          2. Historical Development
                                            1. Early Observations
                                              1. Ancient Understanding of Natural Cycles
                                                1. Early Agricultural Insights
                                                2. Foundational Scientists
                                                  1. Vladimir Vernadsky
                                                    1. G. Evelyn Hutchinson
                                                      1. Alfred Redfield
                                                      2. Key Milestones
                                                        1. Development of Analytical Techniques
                                                          1. Recognition of Global Cycles
                                                          2. Emergence as Distinct Discipline
                                                            1. 20th Century Synthesis
                                                              1. Modern Research Programs
                                                              2. Recent Advances
                                                                1. Molecular Techniques
                                                                  1. Remote Sensing Applications
                                                                    1. Earth System Science Integration
                                                                  2. Fundamental Concepts
                                                                    1. Elements and Stoichiometry
                                                                      1. Major Biogeochemical Elements
                                                                        1. Carbon
                                                                          1. Nitrogen
                                                                            1. Phosphorus
                                                                              1. Sulfur
                                                                                1. Oxygen
                                                                                  1. Hydrogen
                                                                                  2. Minor and Trace Elements
                                                                                    1. Silicon
                                                                                      1. Iron
                                                                                        1. Calcium
                                                                                          1. Potassium
                                                                                            1. Magnesium
                                                                                            2. Elemental Ratios
                                                                                              1. Redfield Ratio
                                                                                                1. C:N:P Ratios in Ecosystems
                                                                                                  1. Stoichiometric Constraints
                                                                                                2. Reservoirs and Fluxes
                                                                                                  1. Types of Reservoirs
                                                                                                    1. Active Reservoirs
                                                                                                      1. Inactive Reservoirs
                                                                                                        1. Exchangeable Reservoirs
                                                                                                        2. Flux Measurements
                                                                                                          1. Units and Calculations
                                                                                                            1. Temporal Variability
                                                                                                            2. Mass Balance Principles
                                                                                                              1. Input-Output Analysis
                                                                                                                1. Steady-State Assumptions
                                                                                                                  1. Non-Steady-State Dynamics
                                                                                                                2. Residence Time
                                                                                                                  1. Definition and Calculation
                                                                                                                    1. Turnover Time vs Residence Time
                                                                                                                      1. Implications for System Response
                                                                                                                        1. Age Distributions in Reservoirs
                                                                                                                        2. Biogeochemical Cycles
                                                                                                                          1. Cycle Components
                                                                                                                            1. Sources
                                                                                                                              1. Sinks
                                                                                                                                1. Transformations
                                                                                                                                  1. Transport Processes
                                                                                                                                  2. Closed vs Open Systems
                                                                                                                                    1. Local vs Global Cycles
                                                                                                                                    2. System Feedbacks
                                                                                                                                      1. Positive Feedback Mechanisms
                                                                                                                                        1. Negative Feedback Mechanisms
                                                                                                                                          1. Threshold Effects
                                                                                                                                            1. Hysteresis in Biogeochemical Systems