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  2. Trophic state index - Wikipedia

    en.wikipedia.org/wiki/Trophic_state_index

    The TSI of a water body is rated on a scale from zero to one hundred. [1] Under the TSI scale, water bodies may be defined as: [1] oligotrophic (TSI 0–40, having the least amount of biological productivity, "good" water quality); mesotrophic (TSI 40–60, having a moderate level of biological productivity, "fair" water quality); or

  3. Dead zone (ecology) - Wikipedia

    en.wikipedia.org/wiki/Dead_zone_(ecology)

    From 2015-2019, 11 different conditions were measured in various areas of the Elizabeth River. Throughout the river, there were consistently high levels of nitrogen and phosphorus, along with high levels of other contaminants contributing to the poor quality of life for bottom feeders along the river.

  4. Freshwater environmental quality parameters - Wikipedia

    en.wikipedia.org/wiki/Freshwater_environmental...

    Phosphorus compounds are usually found as relatively insoluble phosphates in river water and, except in some exceptional circumstances, their origin is agriculture or human sewage. Phosphorus can encourage excessive growths of plants and algae and contribute to eutrophication. If a river discharges into a lake or reservoir phosphate can be ...

  5. Phosphorus - Wikipedia

    en.wikipedia.org/wiki/Phosphorus

    Phosphorus is a member of the pnictogens, together with nitrogen, arsenic, antimony, bismuth, and moscovium, and consequently shares properties with them. Phosphorus is an element essential to sustaining life largely through phosphates, compounds containing the phosphate ion, PO 3− 4.

  6. Abundance of elements in Earth's crust - Wikipedia

    en.wikipedia.org/wiki/Abundance_of_elements_in...

    The composition of the Earth changed after its formation due to loss of volatile compounds, melting and recrystalization, selective loss of some elements to the deep interior, and erosion by water. [ 3 ] : 55 The lanthanides are especially difficult to measure accurately.

  7. Eutrophication - Wikipedia

    en.wikipedia.org/wiki/Eutrophication

    Health problems can occur where eutrophic conditions interfere with drinking water treatment. [57] 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 ...

  8. Plant nutrition - Wikipedia

    en.wikipedia.org/wiki/Plant_nutrition

    Phosphorus levels have to be exceedingly low before visible symptoms appear in such seedlings. In sand culture at 0 ppm phosphorus, white spruce seedlings were very small and tinted deep purple; at 0.62 ppm, only the smallest seedlings were deep purple; at 6.2 ppm, the seedlings were of good size and color. [37] [38]

  9. Lake ecosystem - Wikipedia

    en.wikipedia.org/wiki/Lake_ecosystem

    Similarly, non-reactive phosphorus in the sediment can be remineralized into the reactive form. [2] Sediments are generally richer in phosphorus than lake water, however, indicating that this nutrient may have a long residency time there before it is remineralized and re-introduced to the system. [3]