Aluminum cycle

The aluminum cycle is the biogeochemical cycle by which aluminum is moved through the environment by natural and anthropogenic processes.

Natural fluxes[]

Lithospheric cycle[]

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Related topics Biogeochemistry geochemical cycle chemical cycling environmental chemistry Biosequestration Deep biosphere Ocean acidification acid rain Biogeochemical planetary boundaries
Research groups DAAC GEOTRACES IMBER NOBM SOLAS
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The majority of aluminum cycling takes place in the lithosphere via sedimentary processes, with 99.999% of aluminum cycled within the lithosphere in the form of primary and secondary minerals as well as colloidal phases.^[1] Primary aluminum-rich minerals, such as feldspars, in the Earth's crust are weathered to clay-like materials such as kaolinite. With further weathering, aluminum is transported as particulates in rivers.^[2] Clays generally have low solubility and are eventually returned to crust through sedimentation and subduction.^[1]

Global aluminum cycle

Fluxes are in Gg (gigagrams) Al/yr, and reservoirs are in Gg Al. Most of the aluminum on Earth is located in the mantle and crust of the lithosphere.^[2] From various processes, this aluminum is uplifted through the soil and into the biotic cycle. Most notably, humans find mineral deposits of aluminum in the earth and dig it up to use in various products. This process, which includes the production, fabrication, use, and discarding of aluminum, contributes greatly to the cycling of aluminum through our Earth's biogeochemical cycle.^[2]

Biotic cycle[]

Aluminum enters the biosphere through water and food and then is cycled through the food chain.^[1] Humans, animals, and plants accumulate aluminum throughout their lives as it cycled throughout the food chain. There is no evidence to support aluminum being essential to humans or in any other forms of life.^[1]

Anthropogenic influence[]

Human activity has influenced the aluminum cycle in many ways. Acid rain increases weathering of the lithosphere through sulfuric acid weathering instead of the usual carbonic acid weathering. This alters the aluminum cycle by reducing the availability of silicic acid and lowering the pH of the environment.^[1] The depletion of silicic acid causes the solubility of aluminum to switch from being dependent on relatively stable hydroxyaluminosilicates to much more unstable solubility controls, such as amorphous aluminum hydroxide and organoaluminum complexes. This increased unstableness of aluminum is further enhanced by an aluminum-induced limitation of biologically available phosphate. Anthropogenic acidification of the environment and extraction of aluminum from ores has resulted in increased exposure to aluminum through diet.^[1] Aluminum in cosmetics, food, drink, and in the atmosphere have increased humans' direct contact of the metal.^[1] Recent research suggests possible link between aluminum and chronic diseases, such as Alzheimer's.^[3]

References[]