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The Trophic State Index (TSI) is a classification system designed to rate water bodies based on the amount of biological productivity they sustain. [1] Although the term "trophic index" is commonly applied to lakes, any surface water body may be indexed. The TSI of a water body is rated on a scale from zero to one hundred. [1]
For his 1934 paper, Alfred Redfield analyzed nitrate and phosphate data for the Atlantic, Indian, Pacific oceans and Barents Sea. [1] As a Harvard physiologist, Redfield participated in several voyages on board the research vessel Atlantis, analyzing data for C, N, and P content in marine plankton, and referenced data collected by other researchers as early as 1898.
Health problems can occur where eutrophic conditions interfere with drinking water treatment. [50] Phosphorus is often regarded as the main culprit in cases of eutrophication in lakes subjected to "point source" pollution from sewage pipes. The concentration of algae and the trophic state of lakes correspond well to phosphorus levels in water ...
Nutrients in the soil are taken up by the plant through its roots, and in particular its root hairs.To be taken up by a plant, a nutrient element must be located near the root surface; however, the supply of nutrients in contact with the root is rapidly depleted within a distance of ca. 2 mm. [14] There are three basic mechanisms whereby nutrient ions dissolved in the soil solution are brought ...
Typically, fresh water is defined as water with a salinity of less than 1% that of the oceans – i.e. below around 0.35‰. Water with a salinity between this level and 1‰ is typically referred to as marginal water because it is marginal for many uses by humans and animals. The ratio of salt water to fresh water on Earth is around 50:1.
In sharp contrast, the period between 14,300 and 11,100 years ago, which includes the Younger Dryas interval, was an interval of reduced sea level rise at about 6.0–9.9 mm/yr. Meltwater pulse 1C was centered at 8,000 years ago and produced a rise of 6.5 m in less than 140 years, such that sea levels 5000 years ago were around 3m lower than ...
The reference water levels are used on inland waterways to define a range of water levels allowing the full use of the waterway for navigation. [1] Ship passage can be limited by the water levels that are too low, when the fairway might become too shallow for large ("target", "design") ships, or too high, when it might become impossible for the target ships to pass under the bridges. [1]
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.