Science 10 Lesson 5: Carbon, Nitrogen and Phosphorus Cycles
Objectives By the end of the lesson you should be able to: • Describe how carbon is cycled through an ecosystem • Describe how nitrogen is cycled through an ecosystem • Describe how phosphorus is cycled in an ecosystem
Nutrient Cycles • Megatonnes: million tons of nutrient stored (found in the phosphorus cycle) • 26 megatonnes = 26 000 000 tons • Gigatonnes: billion tons of nutrient (found in the carbon cycle) • 16 gigatonnes = 16 000 000 000 tons • Nitrogen cycle: no amounts given!
Nutrient Cycle • We will look at C, N and P in detail • Stores: places where nutrients accumulate • Nutrients flow into and out of stores • Major stores: atmosphere oceans land sediments
General Nutrient Cycle Overview Add in the details to your general nutrient cycle NATURAL HUMAN Atmosphere Land clearing Agriculture Urban expansion Mining Industry Motorized transport Land producers Oceans consumers consumers producers decomposers decomposers Sediments
Carbon Cycle: pg. 76 • Choose 4 colours and make a legend on your carbon cycle, label: • Stores • Natural pathways • Human pathways • Extra labels (any extra info)
Nitrogen Cycle: pg. 81 • Choose 6 colours and make a legend on your nitrogen cycle, label: • Stores • Nitrogen fixing (Natural pathway!) • Nitrification (Natural pathway!) • Denitrification (Natural pathway!) • Human pathways • Extra labels
Nitrogen Cycle HINTS: • N2 gas is useless, i.e. animals and plants cannot access it in that form • Nitrogen fixation: (cycling N from atmosphere to land) occurs because animals and plants cannot use N2 gas. Nitrogen-fixing bacteria convert N2 into NH4+ • Nitrification: (cycling N on land) nitrifying bacteria convert NH4+ into NO2- and NO3- • Denitrification: (cycling N from land back to atmosphere) denitrifying bacteria convert NO3- to N2
Phosphorus Cycle: pg. 85 • Choose 4 colours and make a legend on your phosphorus cycle, label : • Stores • Natural pathways • Human pathways • Extra labels
Whiteboarding! • With a partner use the Carbon words (on yellow) and try to arrange them into the carbon cycle WITHOUT using your notes or databook! • Try it now with the Nitrogen words (on green) • And finally with Phosphorus words (on pink) • After you have tried your best – use your databook and diagrams for help!
Your Turn! • 3 way Venn Diagram and practice questions: Pg 75 #1-4; Pg 78 #1-4; Pg 83 #1-4; Pg 86 #1-4; Pg 91 #1-19