1. AP BIO Lab 12 Dissolved Oxygen

2. OXYGEN AVAILABILITY Depends on: ~Temperature: Ability to hold oxygen decreases as water temp gets warmer ~ Photosynthetic Activity: In bright light, plants produce more oxygen ~ Decomposition Activity: As organic material decays, microbial processes consume oxygen ~ Mixing/turbulence: Wave action, water falls, and rapids all aerate water and increase oxygen concentration ~ Salinity: As water becomes more salty, it holds less oxygen

3. Temperature Warm water dissolves ~ MORE SOLIDS than cold ~ LESS GAS than cold http://randolphmase.files.wordpress.com/2009/03/glass-of-soda1.jpg – Reason why pop loses it’s fizz as it gets warm

4. PHOTOSYNTHESIS 6 CO 2 + 6 H 2 O +Light energy C 6 H 12 O 6 + 6 O 2 RESPIRATION C 6 H 12 O 6 + 6 O 2 6CO 2 + 6 H 2 O + energy → →

5. Waves, waterfalls, rapids all increase oxygen concentration http://www.waterfall-wallpapers.com/Waterfall/Waterfall-97/ http://www.chinaodysseytours.com/huangshan/photos/waterfall_7.jpg http://www.filetransit.com/images/screen/9fdd62319548bc0715910a209786d26f_Sparkling_Waves_ScreenSaver.jpg

6. Amount of light drops off sharply with increasing depth Modeled by wrapping sample bottles in increasing layers of screen http://biology.clc.uc.edu/courses/bio303/ecotones.htm

7. PRIMARY PRODUCTIVITY = rate at which photosynthesizers produce organic compounds in ecosystem Can be measured by: ~ amount of CO 2 used ~ rate of sugar formation ~ rate of oxygen produced

8. GROSS PRODUCTIVITY = Total production of all organic compounds made by photosynthesis NET PRODUCTIVITY = Organic material that remains after cellular respiration uses some of these compounds for their energy needs

9. Net productivity = Gross productivity - respiraton Determined by measuring oxygen production in light Determined by measuring oxygen consumption in dark w/o Photosynthesis If measure these 2... We can calculate GROSS PRODUCTIVITY

12. PHOSPHATE TEST

13. NITRATE TEST

14. FIXATION OF VIALS

15. http://randolphmase.files.wordpress.com/2009/03/glass-of-soda1.jpg TITRATION Don’t fill or empty syringe past the number markings

17. Continue adding titrating solution until blue color changes to from purple to pale yellow/colorless. If color change does not occur when the ring on the plunger reaches the bottom of the scale, refill the titrator to the zero line and continue titrating. Keep track of volume used.

19. Maximum amount of oxygen can water hold = SATURATION http://www.moderngent.com/media/sponge_466x389.jpg What is the % saturation of a sample with 8 mg/L oxygen at 15° ? What is the % saturation of a sample with 8 mg/L oxygen at 5° ?

20. NITRATES http://justgetthere.us/blog/archives/Threat-of-Nitrate-To-Our-Environment-and-Health..html

21. http://www.scielo.br/img/revistas/sa/v63n2/28839f5.gif PHOSPHATES

22. WHY DO LAKES in SD TURN GREEN IN SUMMER? When an ecosystem receives a LARGE input of limiting nutrient (ie., fertilizer runoff) the population increases dramatically = ___________ REMEMBER YOUR OLD BIO ! ALGAL BLOOM

23. Nitrates & phosphates from fertilizer/manure get washed into the lake. Nutrients are no longer LIMITED. Cause algae to grow fast and cover the surface http://sbt.blob.core.windows.net/storyboards/v1621335/eutrophication_thumb.png

24. Algae block out sunlight needed for photosynthesis by producers below. No photosynthesis → NO O 2 → organisms below start to die. Algae die too when they run out of food http://sbt.blob.core.windows.net/storyboards/v1621335/eutrophication_thumb.png

25. Cellular respiration by decomposers as they break down dead organisms uses up more O 2 http://sbt.blob.core.windows.net/storyboards/v1621335/eutrophication_thumb.png

26. As O 2 in water is depleted, animals and plants die http://sbt.blob.core.windows.net/storyboards/v1621335/eutrophication_thumb.png

27. Gulf of Mexico Dead Zone http://www.ncat.org/nutrients/hypoxia/hypoxia.html The DEADZONE forms each April, generally grows throughout the summer, reaching a peak in late July.

28. Gulf of Mexico Dead Zone At its peak, the nearly lifeless water can span 5,000 to 8,000-plus square miles, an area almost the size of New Jersey http://serc.carleton.edu/microbelife/topics/deadzone/index.html

29. https://nofishleft.files.wordpress.com/2010/11/coastal-dead-zones.jpg

30. NITRATES

31. PHOSPHATES

32. http://backtoessentialsllc.com/our-services/alkaline-therapy/