Rubisco is about 20% of the plant protein and is argued to be the most abundant protein on Earth (Sharkey, 1985). This Explain why N compounds

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2 Rubisco is about 20% of the plant protein and is argued to be the most abundant protein on Earth (Sharkey, 1985). This Explain why N compounds released when organic matter is combusted. 2

3 TRY database, Kattge et al. Global Change Biology 3

4 Field and Mooney

5 From Reich et al 5

6 Here is a case showing good relations between reflectance and canopy nitrogen. This relation has UTILITY. Yet, it has received much criticism from remote sensing experts. Cons,,critics claim it is an artifact. When the bidirectional reflectance is corrected for canopy structure there becomes a negative relation between N and reflectance and they claim the observations conflict with the physics of leaf reflectance in a 3D canopy and how those photons emerge from the canopy Pros see townsend 6

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8 Decomposition, Mineralization and Ammonification are essentially equivalent. All of these processes are mediated by microbes. Some paths are aerobic. Others are Anaerobic 8

9 Immobilization is the conversion of inorganic N to organic form by microbes. As such it is inavailable top plants until the microbes die and decompose. 9

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13 Popular theory produced by Berkeley professor Mary Firestone. N2O is emitted at several steps in the nitrification and denitrification processes, which are mediated by microbes. Nitrification tends to occur by aerobic microbes. Denitrification occurs by different microbes working in anaerobic conditions. 13

14 N loading on the biosphere can lead to gaseous loss of N compounds through nitrification and denitrification. N2O leads to greenhouse warming and loss of ozone in the stratosphere. NOx leads to ozone pollution and aerosols and lower visibility and human health issues 14

15 Pilegaard 2013 Phil Trans Roy Soc B 15

16 0u6e08xdYi8/U35Ie64th0I/AAAAAAAAC0Q/u6bO5FCu_Q/s1600/plant_fixing_nitrogen_large.jpg N2 is converted to ammonium, NH4+ by symbiosis with nitrogen fixing prokaryotes (bacteria and archaea), diazotrophs 16

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18 Fowler et al

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20 BNF, Biological Nitrogen Fixation Fowler et al 2013 Phil Trans Roy Soc B pg?width=800&height=600&carousel=1 20

21 Tg = 10^12 g 21

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23 There are a number of nitrogen compounds in the air 23

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25 Key processes involve Wet and Dry Deposition, Leaching and Lateral Transport, losses include Biomass Burning, Fossil fuel Combustion, Denitrification 25

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27 Pilegaard 2013 Phil Trans Roy Soc B 27

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37 Streets et al 2013 Atmos Environment. Good news on the Nox front across Europe and North America. Clean air act and emissions controls are working Satellite observations from Space. Europe GOME and Schiamachy satellites. US MODIS and MOPPITT, OMI 37

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40 Ammonia sources and sinks revolve around agriculture 40

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43 Example of ammonia budget 43

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45 Nitrogen compounds inter relate with one another and have multiple effects on the environments, both good and bad. Ammonium and nitrate are plant nutrients, fertilizers. But if there is too much produced they can have deliterious effects on the environment including greenhouse gas warming, pollution, ozone depletion, acid rain, and eutrophication or dead zones in lakes and the ocean 45

46 Laughing gas. It is a strong greenhouse gas, it is generally non reactive in the tropophere, so it can diffuse up to the stratosphere and participate in ozone depleting reactions where it is cold and uv light is abundant to produce O singlet D molecules that destroy N2O and produce NO, which directly destroys ozone. 46

47 from HITRAN absorption spectra.. Nitrous oxide has a greenhouse warming potential about 298 times that CO2 for a 100 year time frame. It has a lifetime of about 114 years. 47

48 There has been marked increases in N2O following the development of fertilizers after World War II and the expansion of agriculture to support growing populations with the industrial revolution. Mid 19 th Century N2O concentrations were on the order of 275 ppb. Today, N2O concentrations exceed 310 ppb 48

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54 Can we rely on Organic Farming to Fix Enough N to feed the Worlds Population? 54

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57 Fowler 57

58 Gruber and Galloway, 2008 Nature, f3.2.jpg 58

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62 N run off from fertilizer applied to farms in the Mississippi River basin flow out to the Gulf. These stimulate an algal bloom. Decomposition of dead algal cells consumes oxygen, which becomes depleted and stress sea life 62

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65 Runoff of nitrogen compounds is causing hypoxia in the Gulf of Mexico 65

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68 Data source: N.N. Rabalais, Louisiana Universities Marine Consortium, R.E. Turner, Louisiana State University Funded by: NOAA, Center for Sponsored Coastal Research 68

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73 Typical global budgets for N2O 73