Table 6. 1.1 Organi c matter remineralization reactions based on organic matte r OM with
the composition OM = C106 H175 O42N16 P.
Reaction
Stoichiometry
(1) Aerobi c respiration
OM + 150 O2
  106 CO2 + 16 HNO3 + H3PO4 + 78 H2O
(2) Denit rification
OM + 104 HNO3
  106 CO2 + 60 N2 + H3PO4 + 138 H2O
(3) Manganese reduction
OM + 260 MnO 2 + 174 H2O
  106 CO2 + 8 N2 + H3PO4 + 260 Mn(OH) 2
(4) Iron reduction
OM + 236 Fe2O3 + 410 H2O
  106 CO2 + 16 NH3 + H3PO4 + 472 Fe(OH)2
(5) Sulfate reduction
OM + 59 H2SO4
  106 CO2 + 16 NH3 + H3PO4 + 59 H2S + 62 H2O
(6) Methane
fermentation
(methanogenesis)
OM + 56 H2O
  47 CO2 + 59 CH4 + 16 NH3 + H3PO4
Table 6. 1.2 Free energy changes fo r remineralizat ion reactions (Morel and Hering
[1993]). CH2O represents sucrose.
Reaction
Free energy change
(kJ mol –1 of CH2O)
-476
CH2O + O2  CO2 + H2O
5CH2O + 4 NO3- 2 N2 + 4 HCO3- + CO2+ 3 H2O
-452
CH2O + 3 CO2 + H2O + 2 MnO 2  2 Mn++ + 4 HCO3-
-388
CH2O + 7 CO2 + 4 Fe(OH) 3  4 Fe++ + 8 HCO3- + 3 H2O
-187
2 CH2O + SO4--  H2S + 2HCO3-
-82
2CH2O  CO2 + CH4
-71
Table 6.1.3 Indirect oxidation reactions based on organic matter OM with the
composition OM = C106H175 O42 N16P proposed by Anderson [1995]. The top three rows
depict the coupli ng of m ethane fermentation with anaerobic oxidation of methane by
sulf ate to produce an overall reaction with the stoichiometry of the sulf ate reduction
reaction. The lower three rows depict the coupli ng o f sulf ate reduction with the reaction
of sulfi de and amm onium with oxygen to give an overall reaction that has the same
stoichiometry as aerobic respiration.
Reaction
Stoichiometry
OM + 56 H2O
Methane fermentation
  47 CO2 + 59 CH4 + 16 NH3 + H3PO 4
59 H2SO4 + 59 CH4
Anaerobic oxidation of
methane
  59 CO2 + 118 H2 O + 59 H2S
OM + 59 H2SO4
Overall reaction
  106 CO2 + 16 NH3 + H3 PO4 + 59 H2S + 62 H2O
OM + 59 H2SO4
Sulfa te reduction
  106 CO2 + 16 NH3 + H3 PO4 + 59 H2S + 62 H2O
Oxidation of sulfide and 59 H2S + 16 NH3 + 150 O2
ammonium
  59 H2SO4 + 16 HNO 3 + 16 H2 O
OM + 150 O2
Overall reaction
  106 CO2 + 16 HNO 3 + H3 PO4 + 78 H2 O
Table 6.1.4 Contribution of various sedim ent reminerali zation processes to global
oxidation rate.
Estimate of global organic carbon oxidation rate
Remineralization Reaction
% of Total
Pg C yrΠ1
65.0%
1.6
Aerobic respiration
6.5%
0.16 ± 0.05
Denitrification
~0.6%
0.01 Π0.02
Manganese Reduction
~0.3%
0.003 Π0.010
Iron Reduction
17.9%
0.44
Sulfa te Reduction
9.8%
0.24
Methanogenesis
2.5
TOTAL
Table 6.2.2 Diagenetic equations for a dissolved constituent C in pore water, and a soli d
constituent B in the soli d sedim ents. C has units of mmol mΠ3 of pore water, and B has
units of mmol mΠ3 of dry soli ds.
  C

 
C 
B   C 
B,C 
    w  C       s 

1



r

R





C:B
max 


t
z
z
z
 K B +B   K C +C 
 1    B

 
B
B   C 
B,C 
  1    S  B   1    DB 

1



R




max 

t
z
z 
 z 
K
+B
 B   K C +C 
Table 6.3.1 The relative contribution of various oxidants to organic matter
remi nerali zation at representative sites.
Site
Percent of Total
NO 3
SO 2O2
Mn & Fe
4
Coastal sediments
Danish coast
40
3
57
Cape Lookout Bight
68


Saanich Inlet
76
Continental Slope and Rise
(<1500 m)
Central Calif ornia (3 cores)
29
57
0.8
14
a
Washington State (19 cores)
10
35
55
a
NW Mexico (19 cores)
0
45
55
(³1500 m)
Central Calif ornia (5 cores)
71
17
1.8
10
a
Washington State (4 cores)
62
26
12
a
NW Mexico (5 cores)
60
30
9
(Other)
Indian Ocean
87
12
0.3
0.6
Hatteras Cont. Rise
76
8
1.7
14
Bermuda Rise
78
12
1.4
9
Savu Basin
61
25
6.5
7.2
Deep Sea
Manop H
99
0.8
0.4
Manop M
91
6.9
0.4
Hatteras Abyssal Plain
96
4
-
CH4
32
24
-
Table 6. 5.1 POC budge t (Pg C yr–1). The % is with respect to the global total for each row.
Deep Ocean
Continental margin
Global
(>1000 m)
(<1000 m)
Ocean area (x10 14 km2)
3.221
(92%)
0.276
(8%)
3.497
Water Column POC Budget
a
Production
45 ± 7
(84%)
8.6 ± 0.8
(16%)
53 ± 8
b
Export (100 m)
7.0 ± 2.4
(71%)
2.8 ± 0.9
(29%)
9.8 ± 3.3
c
Remineralization
6.6 ± 2.4
(91%)
0.63 ± 1.13
(9%)
7.3 ± 3.4
Flux to seafloor
0.34 ± 0.14
(14%)
2.2 ± 0.7
(86%)
2.5 ± 0.8
Sediment POC Budget
e
Remineralization
0.24 ± 0.14
(11%)
1.9 ± 0.7
(89%)
2.1 ± 1.3
f
Burial
0.018 ± 0.016 (9%)
0.174 ± 0.066 (91%)
0.19 ± 0.07
Other Sediment Processes
g
DOC flux t o water column
0.080 ± 0.033 (40%)
0.120 ± 0.039 (60%)
0.20 ± 0.07
h
Denitrification
0.032 ± 0.014 (19%)
0.133 ± 0.043 (81%)
0.165 ± 0.054
Table 6. 5.1 POC budge t. The % is with respect to the global total fo r each row.
Deep Ocean Continental margin
Global
(>1000 m)
(<1000 m)
Ocean area (x10 14 km2)
92%
8%
3.497
Water Column POC Budget
Production a
84%
16%
53 ± 8
Export (100 m)b
71%
29%
9.8 ± 3.3
Remineralization c
91%
9%
7.3 ± 3.4
Flux to seafloor
14%
86%
2.5 ± 0.8
Sediment POC Budget
Remineralization e
11%
89%
2.1 ± 1.3
Burial f
9%
91%
0.19 ± 0.07
Other Sediment Processes
DOC flux t o water column g
40%
60%
0.20 ± 0.07
Denitrification h
19%
81%
0.165 ± 0.054
Diagenetic Equations
Pore water:
  C
 ADV(C)  DIFF(C)  SMS(C)
t
Solid particles:
 1    B
 ADV (B)  DIFF(B)  SMS(B)
t
(6.2.1a)
(6.2.1a)
Diffusion in pore water - 1
Fick’s First Law
C
 (z)     s 
z
C
(6.2.2)
Fick's Second Law
 (z)  
C 
DIFF(C)  
   s 
(6.2.3)

z
z 
z 
C
Diffusion in
pore water - 2
Start with
C
 (z)   e 
z
C
(1)
NOTE: There is considerable
confusion in the literature resulting
from the failure to differentiate
clearly between the tortuosity factor
 and the tortuosity .
Advection in pore water

ADV (C)    wPW  C 
z
(6.2.4)
(1) Full equation
Remineralization in
Sediments
B   C 
B,C 
SMS(C)   1    rC:B  Rmax



 K B +B   K C +C 
(2) For C » KC, (e.g., KC,~3 mmol m –3 for O2)
B
B
SMS(C)   1    rC :B  Rmax

(1)
K B +B
(3) For KB » B (ofte n used for aerobic respiratio n)
SMS(C)   1    k  B (2a)
B
Rmax
k  rC:B 
.
(2b)
KB
(4) For C < KC, but where KB » B (generally used for
denitrification , where KB ~ 20 mmo l m-3)
 C 
SMS(C)   1    k  B  
(3a)
 K C +C 
B,C
Rmax
k  rC:B 
,
KB
(5) G-type kinetics
(3b)
n
GT   Gi
(4)
i1
n
SMS(GT )  (1   )   ki  Gi
i1
(5)
(6.2.5)
Diffusion and advection of solid
particles
 
B
DIFF(B)   1    DB 


z
z

ADV (B)  1    S  B 
z
(6.2.9)
(6.2.10)
Bioturbated layer thickness from
radiocarbon
Bioturbation of 210Pb
(1) Full equation
 
 [ 210 Pb] 
210
0
1



D




1


[
Pb]




B
Pb-210


z 
z 
=
 
 APb-210 
1



D

 Pb-210  1    APb-210
  B


z 
z 
(6.2.15)
(2) Assume porosity an d bioturbatio n are constant with depth
 2 APb-210
(6.2.16)
0  DB 
 Pb-210  APb-210
2
z
(3) boundar y conditions APb-210 = (APb-210)0 at z = 0, and APb-210  0 as z

z
APb-210  (APb-210 )0  exp
z*
(6.2.17)
DB
z* 

POC
Equation
O2 Equation