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Resource: used or used up in processes

Iron

Appears in 25 processs and 39 steps. Everything below is linked: open a process to see it in context.

Top processes

Micronutrient availability: pH, redox and plant mobilisation of Fe and Zn

5 steps

Fe3+ solubility from oxides falls about 1000-fold per pH unit, and Zn2+, Cu2+ and Mn2+ about 100-fold per unit
In calcareous soil at pH 7.5 to 8.5 inorganic Fe3+ falls far below the roughly 10^-8 M plants need, so Fe chlorosis appears
Dicots acidify the rhizosphere, reduce Fe3+ and take up Fe2+, while grasses release phytosiderophores that chelate Fe3+
and 2 more in this process

Soil gas exchange and redox

4 steps

Roots and rhizosphere

2 steps

Iron redox cycling and the enzyme latch in wet soil

2 steps

Redox ladder: sequential electron acceptors in waterlogged soil

2 steps

Pedogenesis and soil horizon development

2 steps

Show 19 more processes

Pyrite oxidation and acid sulfate weathering

2 steps

Aerenchyma, radial oxygen loss and the oxidised rhizosphere of wetland plants

2 steps

Disease-suppressive soils and the rhizosphere cry for help

2 steps

Biological processes

1 step

Marine biological pump and ocean life

Marine biological pump and ocean life

1 step

Phytoplankton fix Carbon dioxide using nutrients and light

Ocean carbon exchange and burial

1 step

Phytoplankton fix carbon (marine primary production)

Bacteria and archaea

1 step

Bacterial iron and manganese redox

Phosphorus cycling

1 step

Phosphate sorbs to iron and aluminum oxides and becomes occluded

Mineral-associated organic matter (MAOM) formation

1 step

Ligand exchange with iron and aluminium oxides

Mineral weathering and parent material

1 step

Organic acids and siderophores from roots and fungi chelate metals and dissolve minerals

Soil sulfur cycling

1 step

In waterlogged soil, sulfate-reducing bacteria turn sulfate into sulfide that precipitates with iron

Biological nitrogen fixation: nitrogenase, oxygen protection and regulation

1 step

Fixation is limited by molybdenum, phosphorus and iron supply, and alternative V or Fe nitrogenases are less efficient

Actinomycetes: Streptomyces hyphal life cycle, extracellular enzymes and antibiotics

1 step

Secondary metabolism switches on: antibiotics, siderophores and geosmin made as growth slows

Living soil system

1 step

Atmospheric dust deposition and loess as soil parent material

Atmospheric dust deposition and loess as soil parent material

1 step

Dust iron reaches high-nutrient low-chlorophyll ocean regions and relieves iron limitation of phytoplankton

Pedogenic carbonate accumulation and calcrete formation

1 step

Calcite equilibrium buffers pH at 7.5 to 8.5; phosphate precipitates as Ca phosphates and Fe, Zn and Mn availability falls

Biological nitrogen fixation: free-living and symbiotic

1 step

Nitrogenase needs molybdenum, iron and phosphorus; Mo limits free-living fixation in some tropical forest litter

Nutrient availability and leaching

1 step

Micronutrient availability: pH, redox and plant mobilisation of Fe and Zn

White-rot and brown-rot fungi: two routes to lignin and cellulose decay

1 step

Brown-rot fungi lack class II peroxidases and use Fenton chemistry (Fe2+ + H2O2 gives hydroxyl radicals) to depolymerize cellulose, leaving modified lignin

Often found with

Iron-reducing bacteria 12 Iron oxides 10 Phosphorus 8 Plant roots 8 Hydrogen ions 7 Iron oxides 6 Phosphate 5 Carbon 5 Oxygen 5 Soil solution 5 Phytoplankton 4 Sulfate 4

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