Ecosystem Productivity Topic 4 Statements: M-Q Ecosystem Function Ecosystem Productivity Topic 4 Statements: M-Q

Photosynthesis H2O + Carbon Dioxide (CO2) + Light Energy (ATP) Inputs: H2O + Carbon Dioxide (CO2) + Light Energy (ATP) Outputs: Glucose (C6H12O6)+ Oxygen Result: Energy Transformation from Solar energy to chemical energy (glucose). Produces the raw materials for producing biomass.

Respiration Inputs: Outputs: Glucose (C6H12O6)+ Oxygen Outputs: H2O + Carbon Dioxide (CO2) + Chemical Energy (ATP) Result: Energy Transformation from chemical energy to cellular/heat energy. All organisms do some form of cellular respiration as this is the process of making cell energy (ATP).

Energy transfers and transformations through ecosystems Light energy coming from the sun to Earth’s surface = Some of this radiation is lost through reflection and absorption of LIGHT ENERGY= transfer Some is converted into chemical energy through Photosynthesis = transformation The energy then moves as biomass from one trophic level to the next through Consumption= transfer Much of this chemical energy is lost to heat energy from one trophic level to another through _ Cellular Respiration = transformation This heat energy is re-radiated back to the atmosphere = Transfer

Pathways of Radiation

Types of Productivity Productivity – The conversion of energy into biomass for a given period of time. Units? As Energy KJ/Kcals or Biomass Kg/g Two Types: 1. Primary Productivity: the amount of biomass or energy made by producers through _Photosynthesis_. 2. Secondary Productivity: Manufacture of biomass or energy made by consumers through __Cellular Respirtaion_.

Gross Productivity Def: The total gain in energy or biomass per unit time through either photosynthesis (GPP) or cellular respiration in consumers (GSP). Gross Primary Productivity (GPP) : The total amount of energy fixed by photosynthesis in producers. Gross Secondary Productivity (GSP): the total amount of energy assimilated by consumers.

Net Productivity Some of the GP (whether it is a producer or consumer) is lost as heat through respiration (R). Net Productivity: The quantity of biomass potentially available to the next trophic level. There is NPP = amt of biomass available to primary consumers (minus respiration.) Or NSP = amt of biomass available to secondary consumers(minus respiration.)

Calculations For Primary Productivity NPP = GPP – Respiration *You will normally be given GPP and Respiration*

Calculations For Consumer Production To find the Gross Productivity of a consumer: GSP = Food Eaten - Fecal Losses The Net Productivity of a consumer can be found/calculated in two ways: NSP = GSP – R Or The amount of biomass gained or assimilated (so weight gain) over a set amount of time. Also called maximum sustainable yield.

Conversion Efficiency About how much energy is converted from one trophic level to the next? Is this an exact amount? The exact amount that is converted is called the conversion efficiency. What equation would you use to calculate the actual percent of energy that was passed from one trophic level to the next?

Example #1 Gross Productivity for Phytoplankton = 190 g/m2/yr Respiratory loss by phytoplankton = 64 g/m2/yr Phytoplankton eaten by zooplankton = 56 g/m2/yr Fecal loss by zooplankton = 15 g/m2/yr Respiratory loss by zooplankton = 22 g/m2/yr 1. Find the NPP of Phytoplankton 2. Find the GSP of Zooplankton 3. Find the NSP of Zooplankton 4. Find the efficiency of conversion between the phytoplankton and the zooplankton…..the actual amount of energy passed from one trophic level to the next….should be between 5-20% (because of the Law of 10%).

Answers 1. NPP = GPP-R = 190 - 64 = 126 g/m2/yr 2. GSP = You must subtract the fecal matter from phytoplankton eaten by zooplankton. 56 – 15 = 41 g/m2/yr 3. NSP = GSP-R = 41-22 = 19 g/m2/yr 4. NSP/NPP x 100 = 19/126 x 100 = 15.01%

Example #2 Initial dry mass equivalent of animal = 10g Final dry mass equivalent of animal = 12.3g Initial dry mass of food given = 23.5g Final dry mass of food left = 19.3g Dry mass of fecal matter = .8g GSP = (23.5-19.3) – .8 = 3.4 g/month NSP = (12.3 – 10) = 2.3 g/month Therefore, what is the Respiration? GSP – NSP = 3.4-2.3 = 1.1 g/month