Biology 2483A Lecture Notes - Lecture 21: Loess, Soil, Nitrification
Document Summary
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 (chemical elements required for metabolism and growth). Nutrients enter ecosystems through the chemical breakdown of minerals in rocks or through the fixation of atmospheric gases. All organisms have similar nutrient requirements but amounts and specific nutrients needed vary. Carbon (c) is the main component of structural compounds in plants, while nitrogen (n) is largely tied up in enzymes. Some c4 and cam plants require sodium (all animals require it). Some plants that host n-fixing bacteria require cobalt. Plants and microorganisms take up nutrients in simple, soluble forms from the environment. Animals mostly get nutrients in food as large, complex molecules. Some of these are broken down; others are absorbed intact, such as some amino acids. All nutrients are ultimately derived from abiotic sources: minerals in rocks and gases in the atmosphere.