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8/11/2019 19 Nitrogen Iron Cycle
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Carbon Cycle
Marine Biota
Export Production
Export Production of Organic Carbon
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1) N is a currency to track mass transfers in marine ecosystem
2) N dynamics important to model exchange processes
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8/11/2019 19 Nitrogen Iron Cycle
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8/11/2019 19 Nitrogen Iron Cycle
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Marine Reservoir: 6.3*105Tg N
Sources: 287 Tg N/yr
Atmosphericdeposition: 86Tg N/yr
N2fixation:
125 Tg N/yr
RiverInput: 76Tg N/yr
Codispoti et al. (2001)
D*$"(' Q":'+ ! O5+&'#
Marine Reservoir: 6.3*105Tg N
Sources: 287 Tg N/yr
Sinks: 482 Tg N/yr
Water Columndenitrification:
150 Tg N/yr
Atmosphericdeposition: 86Tg N/yr
N2O
loss: 6Tg N/yr
N2fixation:
125 Tg N/yr
Sedimentation:25 Tg N/yr
Benthicdenitrification:300 Tg N/yr
OrganicN export:1 Tg N/yr
RiverInput: 76Tg N/yr
Codispoti et al. (2001)
D*$"(' Q":'+ ! O5+&'#
Marine Reservoir: 6.3*105Tg N
Sources: 287 Tg N/yr
Sinks: 482 Tg N/yr
Water Columndenitrification:
150 Tg N/yr
Atmosphericdeposition: 86Tg N/yr
N2O
loss: 6Tg N/yr
N2fixation:
125 Tg N/yr
Sedimentation:25 Tg N/yr
Benthicdenitrification:300 Tg N/yr
OrganicN export:1 Tg N/yr
RiverInput: 76Tg N/yr
Codispoti et al. (2001)
-2E+17
0E+00
2E+17
4E+17
5E+17
7E+17
0 1000 2000 3000 4000
Hypothetical Fixed N Evolution
Fixed
N(
Tg)
Time (years)
D*$"(' Q":'+ ! O5+&'#H-'*("- !"#$%&'( O5+&'# V043*#'0
Georgia Tech Biological Oceanography
N Budget Terms
(Tg N y-1)
1970(Delwiche)
1979(Liu)
1985(Codispoti &
Christensen)
1997(Gruber &
Sarmiento)
2001(Codispoti
et al.)
Inputsatmospheric 4.1 49 40 15 56
runoff 30 17 25 41 41N2-fixation 10 30 25 125 125
Total Inputs 44.1 96 90 181 222
Outputs
pelagic denitrification 40 50 60 85 150
sedimentary denitrification 0 10 60 85 300
burial & other 0.2 36 38 19 32
Total Outputs 40.2 96 158 189 482
8/11/2019 19 Nitrogen Iron Cycle
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N* = N 16 P (Gruber & Sarmiento 1997)
N = 25790
N2fixation
Denitrification
Modern TIME
Georgia Tech Biological Oceanography
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8/11/2019 19 Nitrogen Iron Cycle
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NO3
Chlorophyll
Largedetritus
Organic matter
N2 NH4 NO3
Water column
Sediment
Phytoplankton
NH4Mineralization
Uptake
Nitrification
Nitrification
Grazing
Mortality
Zooplankton
Susp.particles
Aerobic mineralizationDenitrification
N2
Fixation
Mix Layerdepth
Oceanic N Cycle Schematic
NH4+
/('70L 4(1(2(+*.(%[$%+5-4%(
BiologicalPump
Respiration !G (kJ/mol)
-119
Denitrification
-113
MnO2reduction
-96.9
Fe oxide reduction
-46.7
Sulfate reduction
-20.5
Methanogenesis
-17.7
H$&*("- D*\'$ H:"+*4%( T']5'(-' D%$'/ ?'$$"(&; K__R
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