8/11/2019 19 Nitrogen Iron Cycle

1/14

Carbon Cycle

Marine Biota

Export Production

Export Production of Organic Carbon

!"#$%&'( *(+ ,$%( -.-/'01(+'$0#*(+"(& #2' 3*$"(' '-%0.0#'3 +.(*3"-0

1) N is a currency to track mass transfers in marine ecosystem

2) N dynamics important to model exchange processes

!"# %& '( )*+( *,&-. /0.+&1(23

8/11/2019 19 Nitrogen Iron Cycle

2/14

!"#$%&'(

! "0 *( '00'(4*/ (5#$"'(# 6%$ *// /"7"(&

%$&*("030 8(5-/'"- *-"+0 *(+ *3"(% *-"+09

! 2*0 3*(. %:"+*4%( 0#*#'0;

8/11/2019 19 Nitrogen Iron Cycle

3/14

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

4/14

N* = N 16 P (Gruber & Sarmiento 1997)

N = 25790

N2fixation

Denitrification

Modern TIME

Georgia Tech Biological Oceanography

!M B"0#$"F54%( T2%'-# B"*Y%#$%>20; "(-/5+"(& !"#$%&'()*#+*; *$' F$%*+/. +"0#$"F5#'+

"( (5#$"'(# >%%$ %-'*("-

8/11/2019 19 Nitrogen Iron Cycle

5/14

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

O'&&"*#%* D*# H7'$7"'