PCB 4043 Chapter Notes - Chapter 22: Acid Rain, Suspended Solids, Parent Material
16 Jun 2016
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Biogeochemistry is the study of the physical, chemical, and biological factors that influence the movement and transformation of elements. Understanding biogeochemistry is important in determining the availability of nutrients. 22. 1: nutrients enter ecosystems through the chemical breakdown of minerals in rocks or through fixation of atmospheric gases. All organisms have similar nutrient requirements but amounts and specific nutrients needed vary. All nutrients are ultimately derived from abiotic sources: minerals in rocks and gases in the atmosphere. Nutrients may be cycled within an ecosystem, repeatedly passing through organisms and the soil or water. Minerals are solid substances with characteristic chemical properties. Elements are released from rock minerals by weathering. Mechanical weathering: physical breakdown of rocks: expansion and contraction from freeze thaw and drying rewetting cycles break rocks into smaller pieces, plant roots and gravity (e. g. , landslides) also contribute, mechanical weathering exposes minerals to the processes of chemical weathering: Chemical reactions release soluble forms of the mineral elements.
