Concepts

Measurement of ¹⁴C content to distinguish between modern plant-derived and ancient shale-derived organic carbon sources

Spatial variations in oxidation-reduction conditions within floodplain environments that can form within microsites, along textural transitions, or along the capillary fringe

The relative proportions of chemical elements in biological systems

The association of uranium with different solid-phase mineral forms that influences uranium mobility between solid and water phases

Formation of coordination complexes between Fe(II) ions and natural organic matter ligands

Acidic water containing elevated metal concentrations generated from oxidation of sulfide minerals in mining-disturbed areas

Rate laws governing the chemical breakdown of primary minerals as functions of temperature, pH, and saturation state

Vertical distribution of plant nutrient uptake from soil surface through saprolite to bedrock

Zone of active mineral dissolution and precipitation reactions that advances through bedrock over time

Energy content of plant materials measured as calories per gram of ash-free oven-dry weight

Organic matter particles larger than 1 mm, including intact leaves and larger detrital fragments

Activity of enzymes secreted by soil microorganisms that catalyze decomposition of organic matter and provide assimilable carbon and nitrogen compounds

the rate of nutrient excretion per unit body mass of an organism

Total amount of living microbial tissue in soil measured as carbon and nitrogen content

Oxygen-containing reactive molecules with considerable environmental importance due to their high reactivity in mediating redox transformations