1. Ecosystem Productivity

2. Assessment Statements 2.5.2: Describe photosynthesis and respiration in terms of inputs, outputs and energy transformations. 2.5.2: Describe photosynthesis and respiration in terms of inputs, outputs and energy transformations. 2.5.5: Define the terms gross productivity, net productivity, primary productivity, and secondary productivity 2.5.5: Define the terms gross productivity, net productivity, primary productivity, and secondary productivity 2.5.6: Define the terms and calculate the values of gross primary productivity (GPP) and net primary productivity (NPP) from given data. 2.5.6: Define the terms and calculate the values of gross primary productivity (GPP) and net primary productivity (NPP) from given data. 2.5.7: Define the terms and calculate the values of gross secondary productivity (GSP) and net secondary productivity (NSP) from given data. 2.5.7: Define the terms and calculate the values of gross secondary productivity (GSP) and net secondary productivity (NSP) from given data.

3. Key terms Gross productivity (GP) Gross productivity (GP) Gross Primary Productivity (GPP) Gross Primary Productivity (GPP) Gross Secondary Productivity (GSP) Gross Secondary Productivity (GSP) Net productivity Net productivity Net Primary Productivity (NPP) Net Primary Productivity (NPP) Net Secondary Productivity (NSP) Net Secondary Productivity (NSP) Primary productivity Primary productivity Secondary productivity Secondary productivity

4. Figure 10.1 Photoautotrophs

5. Photosynthesis in Plants Chloroplasts are the location of photosynthesis in plants Chloroplasts are the location of photosynthesis in plants In all green parts of plants – leaves, stems,… In all green parts of plants – leaves, stems,… Green color from chlorophyll (photosynthetic pigment) Green color from chlorophyll (photosynthetic pigment) Found in cells of mesophyll – interior tissue of leaves Found in cells of mesophyll – interior tissue of leaves Gases exchanges through the stomata Gases exchanges through the stomata Water enters through xylem of roots Water enters through xylem of roots

6. Figure 10.2 Focusing in on the location of photosynthesis in a plant

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

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

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

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

13. Definitions 1.gross productivity – total biomass produced1.gross productivity – total biomass produced 2.net productivity – total biomass produced minus amount used by organism 3.primary productivity – productivity at 1 st trophic level 4.secondary productivity – productivity at higher trophic level 5.gross primary productivity – rate at which producers use photosynthesis to make more biomass 6.net primary productivity – rate at which energy for use by consumers is stored in new biomass

14. Distribution of World Productivity

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

16. Ocean Area vs Productivity

17. Effects of Depth

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

21. Agricultural Land Highly modified, maintained ecosystems Highly modified, maintained ecosystems Goal is increasing NPP and biomass of crop plants Goal is increasing NPP and biomass of crop plants Add in water (irrigation), nutrients (fertilizer) Add in water (irrigation), nutrients (fertilizer) Nitrogen and phosphorous are most often limiting to crop growth Nitrogen and phosphorous are most often limiting to crop growth Despite modification NPP in agricultural land is less than many other ecosystems Despite modification NPP in agricultural land is less than many other ecosystems

23. Productivity Calculations Total Primary Production = Gross Primary Production (GPP)  Amount of light energy converted into chemical energy by photosynthesis per unit time Total Primary Production = Gross Primary Production (GPP)  Amount of light energy converted into chemical energy by photosynthesis per unit time Joules / Meter 2 / year Joules / Meter 2 / year Net Primary Production  GPP – R, or GPP – some energy used for cell respiration in the primary producers (R = respiratory loss) Net Primary Production  GPP – R, or GPP – some energy used for cell respiration in the primary producers (R = respiratory loss) Represents the energy storage available for the whole community of consumers Represents the energy storage available for the whole community of consumers Standing crop = Total living material at a trophic level Standing crop = Total living material at a trophic level

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

25. Measuring Primary Production Measure aspects of photosynthesis Measure aspects of photosynthesis In closed container measure O 2 production, CO 2 uptake over time In closed container measure O 2 production, CO 2 uptake over time Must measure starting amount in environment then amount added by producers Must measure starting amount in environment then amount added by producers Use dissolved oxygen probe or carbon dioxide sensor Use dissolved oxygen probe or carbon dioxide sensor Measure indirectly as biomass of plant material produced over time (only accurate over long timer periods)  this gives NPP Measure indirectly as biomass of plant material produced over time (only accurate over long timer periods)  this gives NPP

26. Light and Dark Bottle Method – for Aquatic Primary Production Changes in dissolved oxygen used to measure GPP and NPP Changes in dissolved oxygen used to measure GPP and NPP Measures respiration and photosynthesis Measures respiration and photosynthesis Measure oxygen change in light and opaque bottles Measure oxygen change in light and opaque bottles Incubation period should range from 30 minutes to 24 hours Incubation period should range from 30 minutes to 24 hours Use B.O.D. bottles Use B.O.D. bottles

27. Take two sets of samples measure the initial oxygen content in each (I) Take two sets of samples measure the initial oxygen content in each (I) Light (L) and Dark (D) bottles are incubated in sunlight for desired time period Light (L) and Dark (D) bottles are incubated in sunlight for desired time period NPP = L – I NPP = L – I GPP = L – D GPP = L – D R = D – I R = D – I Light and Dark Bottle Method – for Aquatic Primary Production

28. Sample Data

29. Method evaluation Tough in unproductive waters or for short incubation times Tough in unproductive waters or for short incubation times Accuracy in these cases can be increased by using radioactive isotopes C14 of carbon Accuracy in these cases can be increased by using radioactive isotopes C14 of carbon Radioactivity measured with scintillation counter Radioactivity measured with scintillation counter

30. Can use satellite imaging: Nutrient rich waters of the North Atlantic

31. Measuring Secondary Productivity Gross Secondary Production Gross Secondary Production Measure the mass of food intake (I) by an organism (best if controlled diet in lab) Measure the mass of food intake (I) by an organism (best if controlled diet in lab) Measure mass of waste (W) (excrement, shedding, etc.) produced Measure mass of waste (W) (excrement, shedding, etc.) produced GSP = I – W GSP = I – W Net Secondary Production Net Secondary Production Measure organism’s starting mass (S) and ending mass (E) for experiment duration Measure organism’s starting mass (S) and ending mass (E) for experiment duration NSP = E-S NSP = E-S

32. Method evaluation GSP method difficult in natural conditions GSP method difficult in natural conditions Even in lab hard to get exact masses for waste Even in lab hard to get exact masses for waste NSP method hard to document mass change in organism unless it is over a long time period NSP method hard to document mass change in organism unless it is over a long time period

33. What types of things effect productivity? What can we measure for an experiment? What can we measure for an experiment? Effects of light exposure – strength, time, color, … Effects of light exposure – strength, time, color, … Effects of temperature Effects of temperature Differences between types of plants Differences between types of plants Differences between types of producers Differences between types of producers Effects of nutrient additions Effects of nutrient additions Effects of salinity Effects of salinity

34. Other parameters to change Terrestrial vs. aquatic Terrestrial vs. aquatic Oxygen, carbon dioxide Oxygen, carbon dioxide Biomass Biomass B.O.D. bottles B.O.D. bottles

35. GPP estimates

36. Problems Dissolved Oxygen (mmol/L) in water samples from Lake Ashby Transparent BottleOpaque Bottle Initial, 6 a.m.0.288 Final, 9 a.m.0.2920.282 Difference+0.004-0.006 1. Write the equation for and calculate the GPP 2.Write the equation for and calculate the NPP 3. Write the equation for and calculate the Respiration

37. Problems 1.The GPP of the producers in the area, large rainforest trees, is 0.0050 g/cm 2 /day and 25% of this productivity is consumed in respiration. Calculate the NPP.