| environ. |
trace compound; trace material; marker 1. Small amount of an easily detected substance that can be used to follow and quantify the flow of materials or movement of organisms not otherwise visible or detectable by ordinary means. 2. An isotope of an element, a small amount of which may be incorporated into a sample of material in order to follow the course of that element through a chemical, biological, or physical process, and thus also follow the larger sample. The tracer may be radioactive, in which case observations are made by measuring the radioactivity; trace material 1. Both metals and non-metals, essential for the metabolic processes of algae, invertebrates and vertebrates. Organisms that derive nearly all their energy via photosynthesis are especially dependent upon dissolved trace substances. 2. Impurities that are present at small but detectable levels |
