{"thcode":2,"term":{"code":1298,"name":"water chemistry","parent":437,"scope":"Branch of chemistry that deals with the elements and compounds in water."},"uf":[],"bt":[{"code":437,"name":"geochemistry","parent":291,"scope":"Study of the distribution of chemical elements and natural compounds on the earth and in the atmosphere and the chemical processes that affect the earth."},{"code":291,"name":"earth sciences","parent":1019,"scope":"Broad term for all science related to the study of the earth."},{"code":1019,"name":"sciences","parent":1,"scope":"Major educational fields, fields of study, and professional groupings within USGS."},{"code":1,"name":"Categories","parent":null,"scope":"Thematic terms for categorizing information resources.  This thesaurus is intended to support finding and understanding scientific information."}],"nt":[{"code":703,"name":"marine chemistry","parent":1298,"scope":"Branch of chemistry that deals with the properties, composition, structure, and interaction of substances in the seas and oceans."}],"rt":[{"code":518,"name":"groundwater quality","parent":1306,"scope":"Fitness of subsurface water for use based on its composition and properties."},{"code":806,"name":"nutrient content (water)","parent":1304,"scope":"Contaminants in water that nourish organisms, especially plants. Includes nitrogen and phosphorus, either of which can lead to the harmful growth of algae and other plants when present to excess in a body of water."},{"code":854,"name":"oxygen content (water)","parent":1304,"scope":"Measurement of the concentration of oxygen dissolved in water, which is an important indicator of the condition of a water body."},{"code":1010,"name":"salinity","parent":1304,"scope":"Measure of the concentration of salts dissolved in a solution."},{"code":1125,"name":"surface water quality","parent":1306,"scope":"Chemical, physical, and biological characteristics of water in lakes, rivers, or streams related to its fitness for use."},{"code":1129,"name":"suspended material (water)","parent":1304,"scope":"Sediment or organic material carried in suspension in the water column, in contrast to material that moves on or near the bottom. May be measured directly by sampling, or indirectly by acoustic or optical backscatter or transmission."},{"code":1301,"name":"water hardness","parent":1304,"scope":"Indicator of the concentration of alkaline salts in water, mainly calcium and magnesium, as a measure of water quality."},{"code":1302,"name":"water pH","parent":1304,"scope":"The negative logarithm of the hydrogen ion concentration or activity of a water solution. Used for expressing both acidity (pH less than 7) and alkalinity (pH greater than 7), with 7 considered neutral."},{"code":1304,"name":"water properties","parent":1174,"scope":"Measurable physical and chemical characteristics of water from different sources."},{"code":1306,"name":"water quality","parent":1174,"scope":"The chemical, physical, and biological characteristics of water, usually in respect to its suitability for a particular purpose."},{"code":1309,"name":"water sampling","parent":379,"scope":"Methods of collecting a representative part of a body of water for testing in controlled conditions."},{"code":1312,"name":"water temperature","parent":1304,"scope":"The degrees of heat of water from a given source at a specific time."}]}