Students: Turn in to period box Mark & Recapture Activity Honor Code signatures Costa Rica meeting slips? – return to me please Mark & recapture make-ups 1st 2nd 4th Adam F. Ryan L. Hank H. Ayla S. -Absent yesterday for LL check 1st 2nd 8th Adam F. Aseel A. Andrea D. Susie O. Ayla S. -Early release tomorrow – bring your calculator Cell phones in bin

Chapter 54: Ecosystems What is an ecosystem? All the organisms living within an area & all the abiotic factors they interact with Energy flows through while chemicals cycle within an ecosystem

Figure 54.2 An overview of energy and nutrient dynamics in an ecosystem Microorganisms and other detritivores Detritus Primary producers Primary consumers Secondary consumers Tertiary consumers Heat Sun Key Chemical cycling Energy flow

Chapter 54: Ecosystems What is an ecosystem? All the organisms living within an area & all the abiotic factors they interact with Energy flows through while chemicals cycle within an ecosystem What is primary productivity? Amount of light energy converted to chemical energy by autotrophs What is the difference between Gross PP & Net PP? GPP = total primary productivity Amount of light energy converted to chemical energy by photosynthesis NPP = GPP – respiration (energy used by organisms) Storage of chemical energy available to consumers

Figure 54.4 Net primary production of different ecosystems Lake and stream Open ocean Continental shelf Estuary Algal beds and reefs Upwelling zones Extreme desert, rock, sand, ice Desert and semidesert scrub Tropical rain forest Savanna Cultivated land Boreal forest (taiga) Temperate grassland Tundra Tropical seasonal forest Temperate deciduous forest Temperate evergreen forest Swamp and marsh Woodland and shrubland 10 20 30 40 50 60 500 1,000 1,500 2,000 2,500 5 15 25 (a) Percentage of Earth’s surface area (b) Average net primary production (g/m2/yr) (c) Percentage of Earth’s net primary production Key Marine Freshwater (on continents) Terrestrial 5.2 0.3 0.1 4.7 3.5 3.3 2.9 2.7 2.4 1.8 1.7 1.6 1.5 1.3 1.0 0.4 125 360 3.0 90 2,200 900 600 800 700 140 1,600 1,200 1,300 250 5.6 1.2 0.9 0.04 22 7.9 9.1 9.6 5.4 0.6 7.1 4.9 3.8 2.3 65.0 24.4 Earth’s surface = 70% H2O

Figure 54.5 Regional annual net primary production for Earth 180 120W 60W 0 60E 120E North Pole 60N 30N Equator 30S 60S South Pole

Chapter 54: Ecosystems What is an ecosystem? All the organisms living within an area & all the abiotic factors they interact with Energy flows through while chemicals cycle within an ecosystem What is primary productivity? Amount of light energy converted to chemical energy by autotrophs What is the difference between Gross PP & Net PP? GPP = total primary productivity Amount of light energy converted to chemical energy by photosynthesis NPP = GPP – respiration (energy used by organisms) Storage of chemical energy available to consumers What happens to energy at each trophic level?

Figure 54.10 Energy partitioning within a link of the food chain Plant material eaten by caterpillar Cellular respiration Growth (new biomass) Feces 100 J 33 J 200 J 67 J

Chapter 54: Ecosystems What is an ecosystem? All the organisms living within an area & all the abiotic factors they interact with Energy flows through while chemicals cycle within an ecosystem What is primary productivity? Amount of light energy converted to chemical energy by autotrophs What is the difference between Gross PP & Net PP? GPP = total primary productivity Amount of light energy converted to chemical energy by photosynthesis NPP = GPP – respiration (energy used by organisms) Storage of chemical energy available to consumers What happens to energy at each trophic level? 5. What does the “Pyramid of Net Production” look like?

Figure 54.11 An idealized pyramid of net production Tertiary consumers Secondary Primary producers 1,000,000 J of sunlight 10 J 100 J 1,000 J 10,000 J - <1% harnessed by autotrophs Rule of 10 = only 10% of stored energy reaches the next trophic level Leads to the “Pyramid of Biomass”…..

Figure 54.12 Pyramids of biomass (standing crop) Trophic level Dry weight (g/m2) Tertiary consumers 1.5 Secondary consumers 11 Primary consumers 37 Primary producers 809 (a) Most biomass pyramids show a sharp decrease in biomass at successively higher trophic levels, as illustrated by data from a bog at Silver Springs, Florida. (b) In some aquatic ecosystems, such as the English Channel, a small standing crop of primary producers (phytoplankton) supports a larger standing crop of primary consumers (zooplankton). Trophic level Primary producers (phytoplankton) Primary consumers (zooplankton) Dry weight (g/m2) 21 4 Pyramids of net productivity & biomass give rise to…..”pyramid of numbers”

Figure 54.13 A pyramid of numbers Trophic level Number of individual organisms Primary producers Tertiary consumers Secondary consumers Primary consumers 3 354,904 708,624 5,842,424

Fig. 54.14 Relative food energy available to the human population at different trophic levels Secondary consumers Primary producers - more energy is available to vegetarians than carnivores

Chapter 54: Ecosystems What is an ecosystem? All the organisms living within an area & all the abiotic factors they interact with Energy flows through while chemicals cycle within an ecosystem What is primary productivity? Amount of light energy converted to chemical energy by autotrophs What is the difference between Gross PP & Net PP? GPP = total primary productivity Amount of light energy converted to chemical energy by photosynthesis NPP = GPP – respiration (energy used by organisms) Storage of chemical energy available to consumers What happens to energy at each trophic level? What does the “Pyramid of Net Production” look like? Let’s consider chemical cycling within an ecosystem….

Figure 54.17 Nutrient Cycles Transport over land Solar energy Net movement of water vapor by wind Precipitation over ocean Evaporation from ocean Evapotranspiration from land Percolation through soil Runoff and groundwater CO2 in atmosphere Photosynthesis Cellular respiration Burning of fossil fuels and wood Higher-level consumers Primary Detritus Carbon compounds in water Decomposition THE WATER CYCLE THE CARBON CYCLE

THE NITROGEN CYCLE THE PHOSPHORUS CYCLE N2 in atmosphere Denitrifying bacteria Nitrifying Nitrification Nitrogen-fixing soil bacteria bacteria in root nodules of legumes Decomposers Ammonification Assimilation NH3 NH4+ NO3 NO2  Rain Plants Consumption Decomposition Geologic uplift Weathering of rocks Runoff Sedimentation Plant uptake of PO43 Soil Leaching THE NITROGEN CYCLE THE PHOSPHORUS CYCLE

Chapter 54: Ecosystems What is an ecosystem? What is primary productivity? What is the difference between Gross PP & Net PP? What happens to energy at each trophic level? What does the “Pyramid of Net Production” look like? Let’s consider chemical cycling within an ecosystem…. What happened at the Hubbard Brooks Experimental Forest? - Nutrients stayed within an ecosystem due to plants

Nitrate concentration in runoff Figure 54.19 Nutrient cycling in the Hubbard Brook Experimental Forest: an example of long-term ecological research (a) Concrete dams and weirs built across streams at the bottom of watersheds enabled researchers to monitor the outflow of water and nutrients from the ecosystem. Nitrate concentration in runoff (mg/L) Deforested Control Completion of tree cutting 1965 1966 1967 1968 80.0 60.0 40.0 20.0 4.0 3.0 2.0 1.0 The concentration of nitrate in runoff from the deforested watershed was 60 times greater than in a control (unlogged) watershed. (c) One watershed was clear cut to study the effects of the loss of vegetation on drainage and nutrient cycling. (b)

Chapter 54: Ecosystems What is an ecosystem? What is primary productivity? What is the difference between Gross PP & Net PP? What happens to energy at each trophic level? What does the “Pyramid of Net Production” look like? Let’s consider chemical cycling within an ecosystem…. What happened at the Hubbard Brooks Experimental Forest? Nutrients stayed within an ecosystem due to plants What is biological magnification? - Concentration of toxins increase in higher trophic levels

Fig. 54.23 Biological magnification of PCBs in a Great Lakes food web Concentration of PCBs Herring gull eggs 124 ppm Zooplankton 0.123 ppm Phytoplankton 0.025 ppm Lake trout 4.83 ppm Smelt 1.04 ppm