1. Ecosystems Primary Productivity Roles of Species in Ecosystems

2. Primary Productivity The fabrication of carbon compounds through photosynthesis or chemosynthesis by bacteria, protists, and plants. The fabrication of carbon compounds through photosynthesis or chemosynthesis by bacteria, protists, and plants. Such organisms contribute the sugars, lipids, and other building blocks for all other consumers in the trophic levels. Such organisms contribute the sugars, lipids, and other building blocks for all other consumers in the trophic levels. Primary productivity determines the amount of energy available in an ecosystem. Primary productivity determines the amount of energy available in an ecosystem.

3. Productivity of Producers: The Rate Is Crucial Gross primary production (GPP) Gross primary production (GPP) – Rate at which an ecosystem’s producers convert solar energy into chemical energy as biomass. Figure 3-20

4. Primary Productivity Gross Primary Productivity (GPP) Gross Primary Productivity (GPP) Rate at which producers can convert solar energy into biomass. Rate at which producers can convert solar energy into biomass. Net Primary Productivity (NPP) Net Primary Productivity (NPP) Rate at which producers make and store photosynthetic products, but also takes into account the needs of the organism to use the products for their own energy requirements Rate at which producers make and store photosynthetic products, but also takes into account the needs of the organism to use the products for their own energy requirements

5. Primary Productivity The general formula for calculating the available biomass in the form of high energy organic compounds is: The general formula for calculating the available biomass in the form of high energy organic compounds is: GPP – respiration rate = NPP These values are often given in mg/L/day or may be expressed in energy units, such as kCal or kJ per day These values are often given in mg/L/day or may be expressed in energy units, such as kCal or kJ per day Average net primary productivity is kcal/m 2 /yr is sometimes referred to as natural capital. Average net primary productivity is kcal/m 2 /yr is sometimes referred to as natural capital.

6. PrimaryProductivity Various ecosystems and biomes show different rates of GPP and NPP Various ecosystems and biomes show different rates of GPP and NPP Terrestrial Terrestrial Tropical rain forest, swamps, marshes Tropical rain forest, swamps, marshes Aquatic Aquatic Salt marshes (nutrients) Salt marshes (nutrients)

7. Primary Productivity Ocean productivity is the greatest overall Ocean productivity is the greatest overall Marine phytoplankton are efficient at various depths because of their different light-absorbing pigments and the vast number of these producers worldwide Marine phytoplankton are efficient at various depths because of their different light-absorbing pigments and the vast number of these producers worldwide

8.  What are nature’s three most productive and three least productive systems?

9. Trophic Level Energy Consumed Waste Energy GPPNPP Producer1,500,00010,0008,000 1 o Consumer 2000160020080 2 o Consumer 1601004010 In the community described in the table above, which of the following represents the respiratory energy (kcal/m 2 /year) used by autotrophic organisms? a) 10b) 200 c) 1,600d) 2,000 e) 10,000 Primary Productivity

10. Trophic level Energy Available (kcal/m 2 /yr) Producers9000 Primary Consumers (herbivores)1500 Secondary Consumers (carnivores)120 Tertiary Consumers (top carnivores)12 Energy flow for Green Springs (kcal/m 2 /yr). Based on the table above, calculate the efficiency of energy transfer (in percent) from: a) Producers to primary consumers b) Primary consumers to secondary consumers c) Secondary consumers to tertiary consumers