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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)

    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.

  5. Redfield ratio - Wikipedia

    en.wikipedia.org/wiki/Redfield_ratio

    That the nitrate to phosphate ratio in the interior of all of the major ocean basins is highly similar is possibly due to the residence times of these elements in the ocean relative to the ocean's circulation time, roughly 100 000 years for phosphorus and 2000 years for nitrogen. [7]

  6. Plant nutrients in soil - Wikipedia

    en.wikipedia.org/wiki/Plant_nutrients_in_soil

    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 ...

  7. Phosphorus - Wikipedia

    en.wikipedia.org/wiki/Phosphorus

    The predominant source of phosphorus in modern times is phosphate rock (as opposed to the guano that preceded it). According to some researchers, Earth's commercial and affordable phosphorus reserves are expected to be depleted in 50–100 years and peak phosphorus to be reached in approximately 2030.

  8. Heats of vaporization of the elements (data page) - Wikipedia

    en.wikipedia.org/wiki/Heats_of_vaporization_of...

    This page was last edited on 12 November 2023, at 16:44 (UTC).; Text is available under the Creative Commons Attribution-ShareAlike 4.0 License; additional terms may apply.

  9. Nutrient pollution - Wikipedia

    en.wikipedia.org/wiki/Nutrient_pollution

    In 2011 EPA reiterated the need for states to fully develop their nutrient standards, noting that drinking water violations for nitrates had doubled in eight years, that half of all streams nationwide had medium to high levels of nitrogen and phosphorus, and harmful algal blooms were increasing. The agency set out a framework for states to ...