Geology Reference
In-Depth Information
apolar compound: a molecule that does not possess functional groups
and undergoes molecular interactions that are dominated by Van-der-
Waals interactions only (e.g., n-alkanes).
aragonite: a solid phase of CaCO
3
.
authigenic: formed, e.g., minerals, in place during or after deposition of
sediment.
authigenic precipitation: solid-phase production in seawater due to a
substance exceeding its solubility product, such as the formation of
ferromanganese nodules.
bacteria: cellular microorganisms incapable of photosynthesis.
benthic: living on the bottom of a water body, e.g., lake.
bioaccumulation: the progressive increase in concentration of a substance
in an organism because the rate of intake via the body surface (e.g., from
water) or in food is greater than the organism's ability to remove the
substance from the body.
bioavailable: the portion of a chemical substance (nutrient, metal, toxin)
that can be absorbed, transported, and utilized physiologically.
biogenic hydrocarbon: an organic compound originating from a recent
biological source, e.g., biogenic volatile organic compounds (VOCs)
emitted from vegetation.
biogenous material: matter produced by the fixation of mineral phases by
marine organisms; notable examples being calcite and opaline silica in
the marine environment.
biomagnification: a food chain or food web phenomenon, whereby a
substance or element increases in concentration at successive trophic
levels.
biomethylation: biologically induced reactions by which methyl groups
are added to metals, metalloids, and organometallic complexes, with
consequent and varied influence on the volatility, bioavailability, and
toxicity of the element concerned.
bioremediation: the use of living organisms, generally bacteria, to clean
up oil spills or remove other pollutants from soil, water, and wastewater.
calcite: a solid phase of CaCO
3
.
carbonate compensation depth (CCD): the depth at the sediment-water
interface at which no calcareous material is preserved in the sediments.
chelate: a complex formed when a central metal atom shares more than
one electron pair with a given ligand thereby forming a ring structure,
which exhibits enhanced stability largely due to the entropy effect of
releasing large numbers of molecules from the co-ordinated water
envelopes.
chelation: the formation of a chelate.
