Biogeochemistry of Wetlands and Soil Properties

Soil Taxonomy

Classification system for soil types and properties.

Andisols

Soils formed from volcanic ash, high in nutrients.

Alfisols

Soils with clay-rich horizons, fertile for agriculture.

Aridisols

Soils in arid regions, often saline or alkaline.

Entisols

Young soils with minimal horizon development.

Gelisols

Soils in cold climates, permafrost present.

Histosols

Organic soils, rich in decomposed plant material.

Inceptisols

Soils with weakly developed horizons, transitional.

Mollisols

Dark, fertile soils, rich in organic matter.

Oxisol

Highly weathered tropical soils, low in nutrients.

Wetland Types

Coastal and inland wetlands with distinct characteristics.

Hydric Soils

Soils saturated with water, supporting wetland vegetation.

Waterlogged Soils

Soils with excess water, affecting oxygen availability.

Flooded Soil

Soil submerged in water, anaerobic conditions prevail.

Upland Soils

Soils found in elevated areas, well-drained.

Biogeochemical Cycles

Recycling of nutrients between living and non-living.

Microbes

Microorganisms playing key roles in soil health.

Acrobes

Microbes requiring oxygen for survival.

Facultative Anaerobes

Microbes that can survive with or without oxygen.

Anaerobes

Microbes that thrive in oxygen-free environments.

Organic Soils

Soils containing significant amounts of organic material.

Peatlands

Wetlands with accumulated peat, rich in carbon.

Chemical Reactions

Transformations involving reactants to products.

Proton Exchange

Reactions where protons (H+) are transferred.

Electron Exchange

Reactions where electrons (e-) are transferred.

Proton and Electron Transfer

Reactions involving both protons and electrons.

Oxidation

Loss of electrons from an atom or molecule.

Reduction

Gain of electrons by an atom or molecule.

Oxidizing Agent

Substance that accepts electrons in a reaction.

Reducing Agent

Substance that donates electrons in a reaction.

Nernst Equation

Calculates redox potential based on concentration.

Redox Potential (Eh)

Measure of tendency to gain or lose electrons.

pH

Measure of acidity or alkalinity of a solution.

Redox Couples

Pairs of oxidizing and reducing agents.

Soil Oxygen Demand

Amount of oxygen required for microbial activity.

Specific Conductance

Ability of water to conduct electricity.

Diel Changes

Daily fluctuations in environmental conditions.

Electrochemical Properties

Characteristics related to electron transfer reactions.

Wetland Soils

Soils saturated with water, influencing redox reactions.

Combustion Reaction

Exothermic reaction producing heat and light.

Displacement Reaction

One element replaces another in a compound.

Synthesis Reaction

Two or more substances combine to form one.

Decomposition Reaction

Single compound breaks down into two or more products.

Aerobic Respiration

Process of producing cellular energy with oxygen.

Oxidation

Loss of electrons in a chemical reaction.

Reduction

Gain of electrons in a chemical reaction.

Oxidant

Substance that gains electrons, causing oxidation.

Reductant

Substance that loses electrons, causing reduction.

Nernst Equation

Calculates electrode potential based on concentration.

Eh

Electrode potential measured in volts.

Eo

Standard electrode potential under standard conditions.

Faraday's Constant

Amount of charge per mole of electrons.

Gas Constant

Constant relating energy, temperature, and volume.

Oxidation-Reduction Potential

Measure of tendency to gain or lose electrons.

Nitrate Respiration

Process of reducing nitrate to nitrogen gas.

Sulfate Respiration

Process of reducing sulfate to sulfide.

Anaerobic Conditions

Environment lacking oxygen, promoting reduction reactions.

Aerobic Conditions

Environment with oxygen, promoting oxidation reactions.

Wetland Soil

Soil type characterized by water saturation.

Drained Soil

Soil that has been dried out.

Electron Donors

Substances that donate electrons in reactions.

Electron Acceptors

Substances that accept electrons in reactions.

Energy Release

Energy produced during oxidation-reduction reactions.

Hydrogen Ion (H+)

Proton involved in acid-base reactions.

Temperature (T)

Measured in Kelvin for Nernst equation.

Oxides

Compounds formed by oxygen and another element.

Mn(IV)

Manganese in the +4 oxidation state.

Fe(III)

Iron in the +3 oxidation state.

Electrode Potentials

Voltage associated with half-cell reactions.

Ease of Reduction

Relative ability of a substance to gain electrons.

Oxidation-Reduction

Reactions involving electron transfer between species.

Mn4+

Manganese ion in the +4 oxidation state.

Mn2+

Manganese ion in the +2 oxidation state.

Se(0)

Elemental selenium in its neutral state.

SeO4

Selenium in the +6 oxidation state.

Redox Potential (mV)

Measure of tendency to gain or lose electrons.

Iron Redox Couple

Equilibrium between Fe2+ and Fe3+ states.

Eh

Redox potential measured in millivolts.

Nitrate Reduction Zone

Soil layer where nitrate is reduced.

Sulfate Reduction Zone

Soil layer where sulfate is reduced.

Methanogenesis

Anaerobic process producing methane from organic matter.

Electron Acceptors

Substances that gain electrons during redox reactions.

Electron Donors

Substances that lose electrons during redox reactions.

Redox Gradients

Variations in redox potential with depth in sediments.

Flooded Organic Soils

Soils saturated with water affecting redox processes.

Sediment Microbial Fuel Cell

Device converting chemical energy to electrical energy using microbes.

Regulators of Eh

Factors influencing redox potential in environments.

Redox Potential

Measure of electron transfer tendency in reactions.

Equilibrium

State where reactants and products remain constant.

Platinum Electrodes

Electrodes used for reversible redox reactions.

pH

Measure of acidity or alkalinity in solutions.

H2CO3

Carbonic acid formed from CO2 and water.

HCO3-

Bicarbonate ion, a key buffer in solutions.

Fe(OH)3

Iron(III) hydroxide, involved in redox reactions.

Flooding Effect

Impact of water saturation on soil properties.

Clay Loam

Soil type with balanced clay and silt content.

Ionic Strength

Concentration of ions in a solution.

Aerobic Respiration

Process converting glucose and oxygen to energy.

Gr (Gibbs Free Energy)

Energy change during a chemical reaction.

C6H12O6

Glucose, a primary energy source for organisms.