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Chemistry and Biogeochemical Cycling: Chemicals dissolved in water

Chemistry and Biogeochemical Cycling: Chemicals dissolved in water. Abundant. Less Abundant (not trace). Chemistry and Biogeochemical Cycling: Solubility of Gases. Chemistry and Biogeochemical Cycling: Oxygen Solubility and temperature. Chemistry and Biogeochemical Cycling:

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Chemistry and Biogeochemical Cycling: Chemicals dissolved in water

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  1. Chemistry and Biogeochemical Cycling: Chemicals dissolved in water Abundant Less Abundant (not trace)

  2. Chemistry and Biogeochemical Cycling: Solubility of Gases

  3. Chemistry and Biogeochemical Cycling: Oxygen Solubility and temperature

  4. Chemistry and Biogeochemical Cycling: Pressure and Solubility

  5. Chemistry and Biogeochemical Cycling: supersaturation http://weberian.handrewlynch.net/

  6. Solubility of oxygen: Differences in fresh and salt water Thank you to Tianlu Shen for this question!

  7. Solubility of oxygen: The salting out effect When dissolved in water, NsCl dissociates into a positively charged sodium ion and a negatively charged chloride ion. Water molecules are attracted to these ions and orient around them as waters of hydration. Due to the polar nature of the water molecule, it associates with ions or other molecules (including other water molecules) possessing a positive or negative charge. Gases such as oxygen dissolve less readily in water that is bonded in this manner. We might say that the salt ‘competes’ with the gases for the water molecules. Where there is a great deal of salt present, as in marine waters, a significant number of water molecules are present as waters of hydration. Thus, less oxygen will dissolve in water with a high salt content than in ‘fresh’ water. Snoeyink, V.L. and D. Jenkins. 1980. Water Chemistry. John Wiley & Sons, New York, New York, 463 pp. [text] http://www.ionizers.org/water.html [images]

  8. Chemistry and Biogeochemical Cycling: Ph In pure water … and thus … and since pH is defined as… for pure water , [Note that a little H+ goes a long way in terms of effect!]

  9. Chemistry and Biogeochemical Cycling: the carbonate system

  10. Chemistry and Biogeochemical Cycling: The carbonate system taking the negative log of both sides … and when pH = pK1 and when pH = pK2

  11. Chemistry and Biogeochemical Cycling: The carbonate system • at pH<pK1, carbonic acid dominates • at pH between pK1 and pK2, bicarbonate dominates; and • at pH>pK2, carbonate dominates

  12. Chemistry and Biogeochemical Cycling: The carbonate system The fraction of DIC present in each form can be calculated as f (pH) (Chapra, 1997, p. 685

  13. Chemistry and Biogeochemical Cycling: The carbonate system and the concentration of each component is given by …

  14. Chemistry and Biogeochemical Cycling: The carbonate system photosynthetic withdrawal of carbon dioxide … According to LeChatlier’s Principle, the equilibrium would move to the left, consuming H+ and raising the pH. While, at first glance, this looks to reduce the concentration of carbonate, the increase in pH re-distributes the DIC species, leading to an increase in the carbonate concentration.

  15. Chemistry and Biogeochemical Cycling: The carbonate system ss demo

  16. Chemistry and Biogeochemical Cycling: Whiting event in lake michigan earthobservatory.nasa.gov

  17. Chemistry and Biogeochemical Cycling: alkalinity

  18. Chemistry and Biogeochemical Cycling: Organic carbon - sources allochthonous: carbon fixed within the watershed

  19. Chemistry and Biogeochemical Cycling: Organic carbon - sources autochthonous: carbon fixed within the lake

  20. Chemistry and Biogeochemical Cycling: Organic carbon - sources “don’t it make your brown eyes blue”

  21. Chemistry and Biogeochemical Cycling: Organic carbon – Redox reactions In each redox reaction, an electron donor contributes electrons and is oxidized (i.e. becomes more positive) and electron acceptor receives electrons and is reduced (i.e. becomes more negative). For oxidation of organic carbon by oxygen, the half-reactions are,

  22. Chemistry and Biogeochemical Cycling: Organic carbon – Ecological Redox series Oxygen Reduction (aerobic respiration) Nitrate reduction (denitrification) Manganese Oxide Reduction Iron Oxy-Hydroxide Reduction Sulfate Reduction Methanogenesis Stoichiometry after Berg et al. 2003 and Boudreau 1996).

  23. Chemistry and Biogeochemical Cycling: Organic carbon – Redox in sediments

  24. Chemistry and Biogeochemical Cycling: Organic carbon – carbon cycle

  25. Chemistry and Biogeochemical Cycling: oxygen

  26. Chemistry and Biogeochemical Cycling: Oxygen – photosynthesis and respiration

  27. Chemistry and Biogeochemical Cycling: Nitrogen - species

  28. Chemistry and Biogeochemical Cycling: Nitrogen – amino acids

  29. Chemistry and Biogeochemical Cycling: Nitrogen cycle

  30. Chemistry and Biogeochemical Cycling: Phosphorus – nutrient limitation The Product The Supplies

  31. Chemistry and Biogeochemical Cycling: Phosphorus – the divided lake

  32. Chemistry and Biogeochemical Cycling: Phosphorus – forms of p in lakes PP PIP POP particulate TP SRP TDP DOP soluble organic inorganic

  33. Chemistry and Biogeochemical Cycling: Phosphorus cycle

  34. Chemistry and Biogeochemical Cycling: iron http://www.flickr.com/photos/inoneear/3498341514/

  35. Chemistry and Biogeochemical Cycling: sulfate

  36. Chemistry and Biogeochemical Cycling: silicon

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