Presentation is loading. Please wait.

Presentation is loading. Please wait.

REDOX: IRON, SULFUR, & SILICA. Redox Potential pE = -log free electrons When corrected to pH 7 (H + = OH - ), called E h When E h positive – oxidizing.

Similar presentations


Presentation on theme: "REDOX: IRON, SULFUR, & SILICA. Redox Potential pE = -log free electrons When corrected to pH 7 (H + = OH - ), called E h When E h positive – oxidizing."— Presentation transcript:

1 REDOX: IRON, SULFUR, & SILICA

2 Redox Potential pE = -log free electrons When corrected to pH 7 (H + = OH - ), called E h When E h positive – oxidizing environment When E h negative – reducing environment

3 Redox vs. pH

4 Redox (mv) of common liquids

5 Example of Redox data

6 pH and ORP in Lake Skiennungen

7

8

9

10 Fe & Mn in oligotrophic and eutrophic lakes

11 Iron and Manganese in a Productive Lake

12 Redox: Sulfur and Iron

13 Particulate Fe and Fe (II) through the year

14 Sulfur and Iron in Mud

15 Fe & Mn in Crooked lake (mesotrophic)

16 Fe & Mn in Little Crooked lake (eutrophic)

17 Transport of Fe in a lake

18 Iron Oxidizing Bacteria Gallionella (an iron-oxidizing bacterium) 4Fe (HCO 3 ) 2 + O 2 + 6H 2 O 4Fe (OH) 3 + 4H 2 CO 3 + 4CO kcal

19 Ferrobacillus iron bacteria 4FeCO 3 + O 2 + 6H 2 O Fe(OH) 3 + 4CO 2

20 Mn cycling relative to O 2

21

22 REDOX and Sulfur

23 S in oligotrophic and eutrophic lakes

24 SO 4 in a mesotrophic hardwater lake

25 SO 4 budget for Linsley Pond

26 ORP, pH, and Sulfur bacteria

27 Autotrophic Sulfur-Oxidizing Bacteria and Iron Transformations Thiobacillus Some of the reactions that it can mediate FeS 2 + 3½O 2 +H 2 O FeSO 4 + H 2 SO 4 2FeSO 4 + ½O 2 + H 2 SO 4 Fe 2 (SO 4 ) 3 + H 2 O

28 Bacterial Transformations of Sulfur Sulfate-Reducing Bacteria (heterotrophic and anaerobic) Sulfur-Oxidizing Bacteria – Chemosynthetic – Pigmented Autotrophic

29 Sulfate-Reducing Bacteria Ex: Desulfovibrio Heterotrophic and anaerobic H 2 SO 4 + 2(CH 2 O) 2CO 2 2H 2 O + H 2 S H 2 SO 4 + 4H 2 H 2 S + 4H 2 O

30 Chemosynthetic Sulfur-Oxidizing Bacteria Ex: Beggiatoa Deposit elemental S inside cell H 2 S + ½O 2 S + H 2 O S + 1½O 2 + H 2 O H 2 SO 4 Ex: Thiobacillus Deposit elemental S outside 2Na 2 S 2 O 3 + O 2 2S + 2Na 2 SO 4

31 Green Sulfur Bacteria Ex: Chlorobium Uses a pigment similar to chlorophyll CO 2 + 2H 2 S LIGHT Food + H 2 O + 2S 2CO H 2 O + H 2 S LIGHT Food + H 2 SO 4

32 Purple Sulfur Bacteria Ex: Chromatium They deposit sulfur intracellularly Same reactions as Chlorobium

33 Purple Non-Sulfur Bacteria Ex: Rhodobacter Na 2 S 2 O 3 +2CO 2 +3H 2 O LIGHT Food + Na 2 SO 4 +H 2 SO 4

34 Microbial-mediated Sulfur cycle in a lake

35 Sulfate reduction in Lake Gek Gel and the Black Sea

36 Distribution of sulfur in meromictic Lake Belovod

37 Abandoned Mine Drainage

38 Microbial Oxidation of Pyrite

39 AMD Discharges

40 Acid Precipitation

41 Si in lakes

42 Some Common Diatoms

43 Si in oligotrophic Lawrence Lake

44 Si and diatom population dynamics in Lake Windermere

45 Dynamics of diatom periphyton and plankton

46 Green Algae and Diatoms


Download ppt "REDOX: IRON, SULFUR, & SILICA. Redox Potential pE = -log free electrons When corrected to pH 7 (H + = OH - ), called E h When E h positive – oxidizing."

Similar presentations


Ads by Google