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Atmospheric CO 2 and Global Net Primary Productivity. Group A14 Zen Bakshi , Hannah Beaugh , Joshua Brown, Patrick Loeffler, Alexander Price. Photosynthesis. Introduction. Freeman, 2011. Introduction. Photosynthesis. 6 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 O₂. Introduction. The Carbon Cycle.
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Atmospheric CO2 and Global Net Primary Productivity Group A14 Zen Bakshi, Hannah Beaugh, Joshua Brown, Patrick Loeffler, Alexander Price
Photosynthesis Introduction Freeman, 2011
Introduction Photosynthesis 6 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 O₂
Introduction The Carbon Cycle Freeman, 2011
Data/Results BioCON Experiment • Does nitrogen have an impact CO₂ Fertilization? • 296 field plots (each 2m x 2m) • Ambient or enriched atmospheric (180 μmol/mol) CO₂ • Ambient or enriched (4gm-2y-1) N soil supply • Biomass was assessed two times a year Reich and Hobbie 2012
Data/Results Discussion Within 3 years plant biomass was similar between ambient nitrogen, and enriched nitrogen soils. However, plants with ambient nitrogen supply did half as well as those with enriched nitrogen over the longer time period Reich and Hobbie 2012
Discussion NPP 2000 – 2009 • Net Primary Productivity has decreased over the past decade due to droughts and an increased dying trend in phototrophs • Increase northern hemisphere was counteracted by a decrease in the southern hemisphere, leading to increase in future food demand, competition, and biofuel production • Rainforests have a major impact on NPP, tropical rainforests account for 61% of global NPP variations • NPP decline in rainforests such as the Amazon attributed to increasing air temperature, versus decline in Asian rainforests was due to a decrease in received solar radiation Maosheng Zhao and Steven W. Running
Data/Results Trend highlights the discrepancy in NPP between Northern and Southern Hemispheres due to a decrease in PDSI (Palmer Drought Index) and sequentially a decrease in NPP PDSI:0 = Normal, -1 = Slight Drought, -2 = Moderate Drought, -3 = Severe Drought NPP 2000 – 2009 Graphical Analysis Analysis Discussion Maosheng Zhao and Steven W. Running
Data/Results Discussion A generally positive correlation exists between NPP and C density in boreal forests. However The study was conducted with increased nitrogen deposition increasing nitrogen available for the trees. = Turnover time Lloyd, J. 1999.
Discussion Factors that correlate with NPP • Temperature • Moisture • Disturbances • Plant Characteristics • Climate • Soil Composition • Resource Availability (Eg. CO2 and Nitrogen) Christopher B. Field, James T. Randerson, and Carolyn M. MalmstrOm.
Conclusion THE PROBLEM WILL NOT FIX ITSELF Net Primary Production is not increasing due to CO₂ in the atmosphere because there are other limiting factors such as nitrogen availability. Human activities are causing NPP to decrease, creating an environment unable to sustain an increasing human population.
Works Cited Christopher B. Field, James T. Randerson, and Carolyn M. MalmstrOm. 1995. Global Net Primary Production: Combining Ecology and Remote Sensing. REMOTE SENS. ENVIRON. 51:74-88 Lloyd, J. 1999. The CO2 dependence of photosynthesis, plant growth responses to elevated CO2 concentrations and their interaction with soil nutrient status, II. Temperate and boreal forest productivity and the combined effects of increasing CO2 concentrations and increased nitrogen deposition at a global scale. Functional Ecology 13: 439-459. Maosheng Zhao and Steven W. Running. 2010. Drought-Induced Reduction in Global Terrestrial Net Primary Production from 2000 Through 2009. Science 20 August 2010: 329 (5994), 940-943 [DOI:10.1126/science.1192666 Peter B. Reich and Sarah E. Hobbie, 2012. Decade-long soil nitrogen constraint on the CO2 fertilization of plant biomass. Nature Climate Changedoi:10.1038/nclimate1694 published online 30 Sep 2012 Scott Freeman, 2011. Photosynthesis. Biological Science. P181, 186. Scott Freeman, 2011. Ecosystems. Biological Science. P1097. Scott Freeman, 2011. An Introduction to Ecology. Biological Science. P1009. Christopher B. Field, James T. Randerson, and Carolyn M. MalmstrOm.