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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. 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.

  4. Dead zone (ecology) - Wikipedia

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

    In fall months, tropical storms begin to enter the Gulf of Mexico and break up the dead zones, and the cycle repeats again in the spring. Aquatic and marine dead zones can be caused by an increase in nutrients (particularly nitrogen and phosphorus) in the water, known as eutrophication. These nutrients are the fundamental building blocks of ...

  5. Water year - Wikipedia

    en.wikipedia.org/wiki/Water_year

    The United States Geological Survey (USGS) defines it as the period between October 1 of one year and September 30th of the next, [2] [3] as late September to early October is the time for many drainage areas in the US to have the lowest stream flow and consistent ground water levels. The water year is designated by the calendar year in which ...

  6. Lake Erie - Wikipedia

    en.wikipedia.org/wiki/Lake_Erie

    Levels ranged from 4.33 to 5.08 feet (1.32–1.55 m) above the datum. [28] Historic Low Water. In the winter of 1934, Lake Erie reached its lowest level at 1.5 feet (0.46 m) below the datum. [28] Monthly low water records were set from July 1934 through June 1935. During this twelve-month period water levels ranged from 1.5 feet (0.46 m) below ...

  7. USDA soil taxonomy - Wikipedia

    en.wikipedia.org/wiki/USDA_soil_taxonomy

    There are 12 soil orders (the top hierarchical level) in soil taxonomy. [2] [3] The names of the orders end with the suffix -sol. The criteria for the different soil orders include properties that reflect major differences in the genesis of soils. [4] The orders are: Alfisol – soils with aluminium and iron.

  8. The Israeli military deployed white phosphorus, a controversial and lethal chemical substance, in its war against Hamas, putting civilians at risk of life-threatening burns, according to the Human ...

  9. Biological roles of the elements - Wikipedia

    en.wikipedia.org/wiki/Biological_roles_of_the...

    phosphorus: 15: 5: Ubiquitous, essential for all forms of life; all nucleic acids contain substantial amounts of phosphorus; it is also essential to adenosine triphosphate (ATP), the basis for all cellular energy transfer; and it performs many other essential roles in different organisms. [11] Toxic in some forms; pure phosphorus is poisonous ...