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AP BIO Lab 12Dissolved Oxygen
OXYGEN AVAILABILITYDepends 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
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
PHOTOSYNTHESIS6 CO2 + 6 H2O +Light energy C6H12O6 +
6 O2
RESPIRATIONC6H12O6 + 6 O2 6CO2 + 6 H2O + energy
→
→
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
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 with8 mg/L oxygen at 5° ?
FIXATION OF VIALS
http://randolphmase.files.wordpress.com/2009/03/glass-of-soda1.jpg
TITRATION
Don’t fill or empty syringe past the number markings
Continue adding titratingsolution until blue color changes to from purpleto pale yellow/colorless.
If color change does notoccur when the ring on theplunger reaches the bottomof the scale, refill thetitrator to the zero line andcontinue titrating.
Keep track of volume used.
Amount of light drops off sharply with increasing depth
Modeled by wrapping sample bottles inincreasing layers of screen
http://biology.clc.uc.edu/courses/bio303/ecotones.htm
PRIMARY PRODUCTIVITY =rate at which photosynthesizers produce organic compounds in ecosystem
Can be measured by:~ amount of CO2 used
~ rate of sugar formation~ rate of oxygen produced
GROSS PRODUCTIVITY =Total production of all organic
compounds made by photosynthesis
NET PRODUCTIVITY =Organic material that remains after
cellular respiration uses some of thesecompounds for their energy needs
Net productivity = Gross productivity - respiraton
Determined bymeasuring oxygen productionin light
Determined by measuringoxygen consumption in dark w/o Photosynthesis
If measure these 2 . . . We can calculate GROSS PRODUCTIVITY
NITRATES
http://justgetthere.us/blog/archives/Threat-of-Nitrate-To-Our-Environment-and-Health..html
NITRATES
http://backtoessentialsllc.com/our-services/alkaline-therapy/