1. OXYGEN IN LAKES, STREAMS, AND RESERVOIRS

2. SOLUBILITY OF OXYGEN IN WATER RELATIVE TO PRESSURE

3. SOLUBILITY OF OXYGEN IN WATER RELATIVE TO TEMPERATURE

4. OXYGEN SOURCES ATMOSPHERE PHOTOSYNTHESIS LOSSES CHEMICAL – HUMIC ACIDS – IRON COMMUNITY METABOLISM

5. RED MUD – BLACK MUD

6. ORTHOGRADE OXYGEN CURVE

7. CLINOGRADE OXYGEN CURVE

8. CHANGE IN SEASONS IN A DIMICTIC LAKE

9. HOW COULD TWO SIMILAR LAKES HAVE SUCH DIFFERENT OXYGEN PROFILES IN SUMMER?

10. CHANGE IN OXYGEN PROFILE THROUGH A SUMMER SEASON

11. HETEROGRADE OXYGEN CURVES

12. SUPPOSE A LAKE HAS THE FOLLOWING CLINOGRADE OXYGEN CURVE AT THE END OF THE SUMMER SEASON

13. CASCADE OF EVENTS LEADING TO TURNOVER WITH CHANGE IN OXYGEN PROFILE

14. OXYGEN CONCENTRATION UNDER CLEAR ICE

15. LATER IN WINTER

16. WARMING OF A LAKE DURING SPRING AND EARLY SUMMER

17. LONGITUDINAL OXYGEN CONCENTRATION IN A STREAM

18. DAILY OXYGEN CYCLE

19. OXYGEN CYCLE IN LAKE ERIE BASIN

21. LAKE NASSER Surface area [km 2 ] 6,000 Volume [km 3 ] 162 Maximum depth [m] 110 Mean depth [m] 70 Water level Regulated Normal range of annual water level fluctuation [m] 25 Length of shoreline [km] ca. 9,000 Catchment area [km 2 ] 2,849,000

22. LONGITUDINAL PROFILE OF LAKE NASSER

23. LAKE NASSER OXYGEN

25. OXYGEN DEFICIT INCREASES WITH INCREASED PHYTOPLANKTON PRODUCTION INCREASED PHOSPHATE INCREASE IN HYPOLIMNETIC VOLUME

26. OXYGEN DEFICIT PROPORTIONAL TO THE INVERSE OF THE EPILIMNETIC TRANSPARENCY Example: Diamond Lake in Oregon

29. DO DYNAMICS IN SURFACE WATERS (WETZEL, TABLE 9-2) STREAMRESERVOIRLAKE DOUSUALLY HIGHHIGH HORIZONTAL VARIABILITY, USUALLY WARMER SMALL HORIZONTAL VARIABILITY, USUALLY COOLER OXYGEN UPTAKE FROM ATMOSPHERE HIGHMODERATEVARIABLE TO LOW DIURNAL VARIATION IN OXYGEN HIGHMODESTLOW