lab #12 do 2 & primary productivity aquatic primary producers

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Lab #12 dO 2 & Primary Productivity

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Page 1: Lab #12 dO 2 & Primary Productivity Aquatic Primary Producers

Lab #12

dO2 & Primary Productivity

Page 2: Lab #12 dO 2 & Primary Productivity Aquatic Primary Producers
Page 3: Lab #12 dO 2 & Primary Productivity Aquatic Primary Producers

Aquatic Primary Producers

Page 4: Lab #12 dO 2 & Primary Productivity Aquatic Primary Producers

Gall Ball Parasitism

Page 5: Lab #12 dO 2 & Primary Productivity Aquatic Primary Producers

Decomposer

Page 6: Lab #12 dO 2 & Primary Productivity Aquatic Primary Producers

Decomposers

Page 7: Lab #12 dO 2 & Primary Productivity Aquatic Primary Producers

Terrestrial & Aquatic Producers

Page 8: Lab #12 dO 2 & Primary Productivity Aquatic Primary Producers

Primary Productivity• A good measure of the health of an

ecosystem is its primary productivity

• A way you can do this is to measure the amount of activity performed by the autotrophs of the system.

Page 9: Lab #12 dO 2 & Primary Productivity Aquatic Primary Producers

• Remember that some captured photosynthetic energy is stored in plant tissue, and that plants themselves are eaten by the heterotrophs…

• So, the total amount of photosynthesis is a measure of the first (primary) energy stored in an ecosystem

Page 10: Lab #12 dO 2 & Primary Productivity Aquatic Primary Producers

The Oxygen CycleAtmospheric O2

and dissolved O2

CellularRespiration

Photo-synthesis

H2O

CO2

Page 11: Lab #12 dO 2 & Primary Productivity Aquatic Primary Producers

Productivity• Gross productivity - total amount of

energy photosynthesized by the autotrophs…

• Net productivity - total amount of energy available to the heterotrophs

• How can productivity be measured?

Page 12: Lab #12 dO 2 & Primary Productivity Aquatic Primary Producers

The net equation for photosynthesis:

6CO2 + 6 H2O ----------> C6H12O6 + 6O2

So, you can simply measure the amount of O2 produced, right? Well, not quite. The plant also performs cellular respiration:

C6H12O6 + 6O2 ----------> 6CO2 + 6 H2O

It makes a lot of energy, uses some, then provides the net energy to the heterotrophs...

Photosynthesis & Respiration

Page 13: Lab #12 dO 2 & Primary Productivity Aquatic Primary Producers

• Plant in light:Measure O2 produced after photosynthesis and respiration…NET

Gross Productivity

• Plant in dark:Measure O2 used up in cellular respiration...

• Calculate:Subtract dark measurement from light measurement to get gross primary productivity...

30+20

-10