1. Topic 2.3: Energy Productivity

2. Productivity Thursday 11/15
Do Now: Please take out your lab from yesterday. Be ready to share your Rf values for each pigment.

4. Energy Processes Photosynthesis (Green Plants)
sunlight +water + carbon dioxide  oxygen + sugars
Respiration (All living things)
oxygen + sugars  ATP +water + carbon dioxide
ATP is molecular energy storage

5. Producers Make their own food - photoautotrophs, chemoautotrophs
Convert inorganic materials into organic compounds
Transform energy into a form usable by living organisms

6. Photosynthesis Inputs – sunlight, carbon dioxide, water
Outputs – sugars, oxygen
Transformations – radiant energy into chemical energy, inorganic carbon into organic carbon

7. Respiration Inputs - sugars, oxygen
Outputs - ATP, carbon dioxide, water
Transformations – chemical energy in carbon compounds into chemical energy as ATP, organic carbon compounds into inorganic carbon compounds

8. Definitions gross productivity – total biomass produced
net productivity – total biomass produced minus amount used by organism
primary productivity – productivity at 1st trophic level
secondary productivity – productivity at higher trophic level
gross primary productivity – rate at which producers use photosynthesis to make more biomass
net primary productivity – rate at which energy for use by consumers is stored in new biomass

9. Distribution of World Productivity

10. Gross Productivity Varies across the surface of the earth
Generally greatest productivity
In shallow waters near continents
Along coral reefs – abundant light, heat, nutrients
Where upwelling currents bring nitrogen & phosphorous to the surface
Generally lowest
In deserts & arid regions with lack of water but high temperatures
Open ocean lacking nutrients and sun only near the surface

11. Net Productivity Some of GPP used to stay alive, grow and reproduce
NPP is what’s left
Most NPP
Estuaries, swamps, tropical rainforests
Least NPP
Open ocean, tundra, desert
Open ocean has low NPP but its large area gives it more NPP total than anywhere else

12. Productivity Calculations
Total Primary Production = Gross Primary Production (GPP)  Amount of light energy converted into chemical energy by photosynthesis per unit time
Joules / Meter2 / year
Net Primary Production  GPP – R, or GPP – some energy used for cell respiration in the primary producers
Represents the energy storage available for the whole community of consumers
Standing crop = Total living material at a trophic level

13. More Productivity Calculations
Producers:
NPP = GPP – R
Consumers:
GSP = Food eaten – fecal losses
NSP = change in mass over time
NSP = GSP – R