Post on 27-Feb-2021
Evolution of the Ocean’sBiological Pump
Andy Ridgwell
MesoproterozoicNeoproterozoic
Phanerozoic
Cm
EraEon Proterozoic Archean
Paleoproterozoic
Phanerozoic
Cenozoic Mesozoic Paleozoic
KPgNg J T P C D OPeriod
200015001000500 2500 3000 35004003002001000Time (Ma)
Evolution of the Biological Pump
Evolution of the Biological Pump
Coccolithophorids Radiolaria
DinoflagellatesDiatoms
Acritarchs
Ma
rtin
[1
99
5]
Major changes in plankton assembledge
Foraminifera
MesoproterozoicNeoproterozoic
Phanerozoic
Cm
EraEon Proterozoic Archean
Paleoproterozoic
Phanerozoic
Cenozoic Mesozoic Paleozoic
KPgNg J T P C D OPeriod
200015001000500 2500 3000 35004003002001000Time (Ma)
Evolution of the Biological Pump
Coccolithophorids Radiolaria
DinoflagellatesDiatoms
Acritarchs
Ma
rtin
[1
99
5]
Major changes in plankton assembledge
Foraminifera
0
1000
2000
3000
4000
5000
6000
7000
? ?Occurrence of ice ages (relative intensity)
Cro
we
ll [1
999]
Royer et al. [2004]
atmosphericpCO (ppm)2
MesoproterozoicNeoproterozoic
Phanerozoic
Cm
EraEon Proterozoic Archean
Paleoproterozoic
Phanerozoic
Cenozoic Mesozoic Paleozoic
KPgNg J T P C D OPeriod
200015001000500 2500 3000 35004003002001000Time (Ma)
deepocean
surfaceocean
CO fixation2
C oxidationorg
C oxidationorg
Evolution of the Biological Pump
Both physical/geochemical and biological/ecological changes occurring through Earth history will affect the processes that govern the partitioning of carbon (and alkalinity) between the surface ocean (and hence atmosphere) and ocean interior, and conversely, oxygen.
MesoproterozoicNeoproterozoic
Phanerozoic
Cm
EraEon Proterozoic Archean
Paleoproterozoic
Phanerozoic
Cenozoic Mesozoic Paleozoic
KPgNg J T P C D OPeriod
200015001000500 2500 3000 35004003002001000Time (Ma)
50
50 50
100
100
100 100
150150
150
150
200
200 200250 250
300
50
50 50
100
100
100 100
150150
150
150
200
200 200250 250
300
MesoproterozoicNeoproterozoic
Phanerozoic
Cm
EraEon Proterozoic Archean
Paleoproterozoic
Phanerozoic
Cenozoic Mesozoic Paleozoic
KPgNg J T P C D OPeriod
200015001000500 2500 3000 35004003002001000Time (Ma)
0 30 60 90-30-60-90
-1Dissolved oxygen (mmol kg )
0 300
De
pth
(km
)
0
4
2
5
1
3
Modern Pacific (zonal mean)
0 30 60 90-30-60-90
-1Dissolved oxygen (mmol kg )
0 300
-1Dissolved H S (mmol kg )2
300 0
Evolution of the Biological Pump
==?
High atmospheric pO2 Low atmospheric pO2
(1) Interrogating the biological pump in silico.
(2) The fundamental importance ... or not ... of the advent of pelagic calcification and mineral ‘ballasting’ of particulate organic matter fluxes.
(3) Extinctions as a window onto the biological pump components.
(4) The fundamental importance ... or not ... of physical ocean changes and particularly warming.
(5) What came before the (vertical) particulate carbon pump?
Evolution of the Biological Pump: TALK OUTLINE
MesoproterozoicNeoproterozoic
Phanerozoic
Cm
EraEon Proterozoic Archean
Paleoproterozoic
Phanerozoic
Cenozoic Mesozoic Paleozoic
KPgNg J T P C D OPeriod
200015001000500 2500 3000 35004003002001000Time (Ma)
Evolution of the Biological Pump: in silico
MesoproterozoicNeoproterozoic
Phanerozoic
Cm
EraEon Proterozoic Archean
Paleoproterozoic
Phanerozoic
Cenozoic Mesozoic Paleozoic
KPgNg J T P C D OPeriod
200015001000500 2500 3000 35004003002001000Time (Ma)
! calculate carbonate alkalinity
loc_ALK_DIC = dum_ALK & & - loc_H4BO4 - loc_OH - loc_HPO4 - 2.0*loc_PO4 - loc_H3SiO4 - loc_NH3 - loc_HS & & + loc_H + loc_HSO4 + loc_HF + loc_H3PO4
! estimate the partitioning between the aqueous carbonate species
loc_zed = ( & & (4.0*loc_ALK_DIC + dum_DIC*dum_carbconst(icc_k) - loc_ALK_DIC*dum_carbconst(icc_k))**2 + & & 4.0*(dum_carbconst(icc_k) - 4.0)*loc_ALK_DIC**2 & & )**0.5 loc_conc_HCO3 = (dum_DIC*dum_carbconst(icc_k) - loc_zed)/(dum_carbconst(icc_k) - 4.0)
loc_conc_CO3 = & & ( & & loc_ALK_DIC*dum_carbconst(icc_k) - dum_DIC*dum_carbconst(icc_k) - & & 4.0*loc_ALK_DIC + loc_zed & & ) & & /(2.0*(dum_carbconst(icc_k) - 4.0))
loc_conc_CO2 = dum_DIC - loc_ALK_DIC + & & ( & & loc_ALK_DIC*dum_carbconst(icc_k) - dum_DIC*dum_carbconst(icc_k) - & & 4.0*loc_ALK_DIC + loc_zed & & ) & & /(2.0*(dum_carbconst(icc_k) - 4.0))
loc_H1 = dum_carbconst(icc_k1)*loc_conc_CO2/loc_conc_HCO3
loc_H2 = dum_carbconst(icc_k2)*loc_conc_HCO3/loc_conc_CO3
open oceansea ice
terrestrialbiota
atmosphere
marine biota
sed
imen
ts
soils
land surface and hydrology
icesheet
2D energy-moisture balance(no clouds, dynamics)
fully 3D (‘reducedphysics’)
ocean
surf
ace layer
bioturbatedzone of 1 cm
sedimentstack layers
partially-filledupper-most
layer
bio
turb
ati
on
al
mix
ing
non-bioturbated
zone ofburied layers
simplifiedthermo-dynamic
Includes ‘main’ climate feedbacks
Nutrients: P, N, Fe, Si
Trace metals: Fe, Cd, Mo13 14
Isotope tracers: C, C, 7 15 30 34 44 144
Li, N, Si, S, Ca, Nd
‘Fast’: ~5,000 years per 24 single core hours
Simulation of the marine sedimentary record‘GENIE’
!
Evolution of the Biological Pump: in silico
tinyurl.com/kmjhe4s
MesoproterozoicNeoproterozoic
Phanerozoic
Cm
EraEon Proterozoic Archean
Paleoproterozoic
Phanerozoic
Cenozoic Mesozoic Paleozoic
KPgNg J T P C D OPeriod
200015001000500 2500 3000 35004003002001000Time (Ma)
!
Coccolithophorids Radiolaria
DinoflagellatesDiatoms
Acritarchs
Ma
rtin
[1
99
5]
Major changes in plankton assembledge
Foraminifera
MesoproterozoicNeoproterozoic
Phanerozoic
Cm
EraEon Proterozoic Archean
Paleoproterozoic
Phanerozoic
Cenozoic Mesozoic Paleozoic
KPgNg J T P C D OPeriod
200015001000500 2500 3000 35004003002001000Time (Ma)
Evolution of the Biological Pump:The Mesozoic planktic calcifier revolution
Coccolithophorids Radiolaria
DinoflagellatesDiatoms
Acritarchs
Ma
rtin
[1
99
5]
Major changes in plankton assembledge
Foraminifera
MesoproterozoicNeoproterozoic
Phanerozoic
Cm
EraEon Proterozoic Archean
Paleoproterozoic
Phanerozoic
Cenozoic Mesozoic Paleozoic
KPgNg J T P C D OPeriod
200015001000500 2500 3000 35004003002001000Time (Ma)
Evolution of the Biological Pump:The Mesozoic planktic calcifier revolution
Evolution of the Biological Pump:Planktic carbonate production and ‘ballasting’
00
-2-1
Flu
x of P
OC
(g m
yr
)
1
2
3
4
5
6
7
10 20 30 40-2 -1Flux of CaCO (g m yr )3
00
1
2
3
4
5
6
7
10 20 30 40-2 -1Flux of opal (g m yr )
00
1
2
3
4
5
6
7
10 20 30 40-2 -1Flux of detrital (g m yr )
2R = 0.49
2R = 0.13
2R = 0.22
Compilation of sediment trap observations: depths >= 2000 m (to exclude hydrodynamically distorted fluxes and relationships) and differentiated by basin:
, , , .
[Wlison et al., 2012; GBC 26, doi:10.1029/2012GB004398]
cyan == Atl yellow == Ind green == Pac magenta == SO
13
dC
(‰
)
1.0
1.5
2.0
2.5
3.0
65.2 65.3 65.4 65.5 65.6
Time (Ma)Ridgwell et al. [in prep]
1210
465Planktic(bulk carbonate)
Benthic(foraminifera)
Paleogene Cretaceous
Evolution of the Biological Pump: ‘Hiccups’(temporary disruption or removal of one or more processes)
65.2 65.3 65.4 65.5 65.6
Time (Ma)
13
dC
(‰
)
1.0
1.5
2.0
2.5
3.0
Ridgwell et al. [in prep]
1210
465Planktic(bulk carbonate)
Benthic(foraminifera)
Evolution of the Biological Pump: ‘Hiccups’(temporary disruption or removal of one or more processes)
high nutrient & DIC13
low d C
low nutrient & dissolvedinorganic carbon (DIC)
13high d C
13
dC
GR
AD
IEN
T
(microbial) degradation:organic matter ® nutrients+DIC
Biological productivity:nutrients+DIC ® organic matter
gra
vit
ati
on
al sett
lin
g
up
wellin
g a
nd
mix
ing
of n
utrie
nts
an
d D
IC
-20 to -30‰
Evolution of the Biological Pump: ‘Hiccups’
65.2 65.3 65.4 65.5 65.6
Time (Ma)
13
dC
(‰
)
1.0
1.5
2.0
2.5
3.0
Ridgwell et al. [in prep]
1210
465
Severe extinction amongstcalcifying plankton
(and less interesting creaturessuch as dinosaurs etc.)
Planktic(bulk carbonate)
Benthic(foraminifera)
(biogenic mineral flux == 0)&&
(organic carbon flux == 0)=> ballasting == .true.
Evolution of the Biological Pump: ‘Hiccups’
Oce
an d
epth
(km
)
5
4
3
2
1
0
13d C (‰)DIC
-0.5 0.0 0.5 1.5 2.51.0 2.0 3.0
modern observations (Pacific mean)
0 60 120-90
0
90
180-120 -60-180
0
Ocean depth (km)3 6
Evolution of the Biological Pump: ‘Hiccups’
Oce
an d
epth
(km
)
5
4
3
2
1
0
13d C (‰)DIC
-0.5 0.0 0.5 1.5 2.51.0 2.0 3.0
0 60 120-90
0
90
180-120 -60-180
0
Ocean depth (km)3 6
model vs. modern observations
Evolution of the Biological Pump: ‘Hiccups’
‘Suess Effect’
!
Oce
an d
epth
(km
)
5
4
3
2
1
0
13d C (‰)DIC
-0.5 0.0 0.5 1.5 2.51.0 2.0 3.0
0 60 120-90
0
90
180-120 -60-180
0
Ocean depth (km)3 6
Evolution of the Biological Pump: ‘Hiccups’
model ( ) vs.13choosing: d C = -4.5‰atm latest Maastrichtian proxies
!
Oce
an d
epth
(km
)
5
4
3
2
1
0
13d C (‰)DIC
-0.5 0.0 0.5 1.5 2.51.0 2.0 3.0
Evolution of the Biological Pump: ‘Hiccups’
model vs. early Paleogene
!
Oce
an d
epth
(km
)
5
4
3
2
1
0
13d C (‰)DIC
-0.5 0.0 0.5 1.5 2.51.0 2.0 3.0
0% biological activity
Evolution of the Biological Pump: ‘Hiccups’ !
-90 -60 -30 0 6030 90
Depth
(km
)
5
S N13
dC
(‰
)
3.0
-0.5
4
3
2
1
0
bio
tic
Evolution of the Biological Pump: ‘Hiccups’
13Modern Pacific zonal d C profile(DIC)
!
-90 -60 -30 0 6030 90
Depth
(km
)
5
S N13
dC
(‰
)
3.0
-0.5
4
3
2
1
0
Depth
(km
)
5
4
3
2
1
0
increasing fractionation between pCO and [CO ]2 2
with decreasing temperature towards to poles
ab
ioti
cb
ioti
c
!
Oce
an d
epth
(km
)
5
4
3
2
1
0
13d C (‰)DIC
-0.5 0.0 0.5 1.5 2.51.0 2.0 3.0
Evolution of the Biological Pump: ‘Hiccups’
30-40% biological activity
Answer:
A somewhat reduced biological pump ...
Oce
an d
epth
(km
)
5
4
3
2
1
0
13d C (‰)DIC
-0.5 0.0 0.5 1.5 2.51.0 2.0 3.0
shallow (150 m) organic matter remineralization
Evolution of the Biological Pump: ‘Hiccups’
Answer:
A somewhat reduced biological pump ...
... or, a strange and different biological pump, consistent with profound ecological change post impact?
Evolution of the Biological Pump:Planktic carbonate production and ‘ballasting’
00
-2-1
Flu
x of P
OC
(g m
yr
)
1
2
3
4
5
6
7
10 20 30 40-2 -1Flux of CaCO (g m yr )3
00
1
2
3
4
5
6
7
10 20 30 40-2 -1Flux of opal (g m yr )
00
1
2
3
4
5
6
7
10 20 30 40-2 -1Flux of detrital (g m yr )
2R = 0.49
2R = 0.13
2R = 0.22
Compilation of sediment trap observations: depths >= 2000 m to exclude hydrodynamically distorted fluxes and relationships, and differentiated by basin:
, , , .
[Wlison et al., 2012; GBC 26, doi:10.1029/2012GB004398]
cyan == Atlantic yellow == Indian green == Pacificmagenta == Southern Ocean
Spatial distribution of carrying capacity (ballasting) coefficients calculated using geographically weighted regression
analysis for CaCO .3
Wilson et al. [2012]
Evolution of the Biological Pump:Planktic carbonate production and ‘ballasting’
Evolution of the Biological Pump:Ocean Carbon Cycling and Oxygenation in Warm Climates
? ?
‘ic
e-h
ou
se’
‘ho
t-h
ou
se’
‘ho
t-h
ou
se’
‘ic
e-h
ou
se’
MesoproterozoicNeoproterozoic
Phanerozoic
Cm
EraEon Proterozoic Archean
Paleoproterozoic
Phanerozoic
Cenozoic Mesozoic Paleozoic
KPgNg J T P C D OPeriod
200015001000500 2500 3000 35004003002001000Time (Ma)
(warm == stratified) && (stratified == anoxic) == .true.
???( ‘stratified’ || ‘sluggish’ || ‘stagnant’ )
Evolution of the Biological Pump:Ocean Carbon Cycling and Oxygenation in Warm Climates
tropics poles
Evolution of the Biological Pump:Ocean Carbon Cycling and Oxygenation in Warm Climates
0
0
0
04 4
4
4
4
8
8
812
12
12
16
16
20
20
−20
−20
−16
−16−12
−12
−12−8
−8
−8
−8
−8 −8
−8
−4
−4
−4
−4
−4
−40
0
0
0
0 30 60 90-30-60-90
De
pth
(km
)
0
4
2
5
1
3
S
-180 -120 -60 60-90
0
90
0 120 180
N
-1D
isso
lve
d o
xyg
en
(m
mo
l kg
)
0
50
100
150
200
250
x4 CO reference simulation2
Benthic (>1000m) [O ]2
Evolution of the Biological Pump:Ocean Carbon Cycling and Oxygenation in Warm Climates
!
0
0
0
04 4
4
4
4
8
8
812
12
12
16
16
16
20
20
−20
−20−16
−16
−16−12
−12
−12−8
−8
−8
−8
−8
−8
−8
−4
−4
−4
−4
−4
−40
0
0
0
0 30 60 90-30-60-90
De
pth
(km
)
0
4
2
5
1
3
S
-180 -120 -60 60-90
0
90
0 120 180
N
-1D
isso
lve
d o
xyg
en
(m
mo
l kg
)
0
50
100
150
200
250
x8 CO @ 10,000 yrs2
(started from end of the x4 simulation)
Benthic [O ]2
Evolution of the Biological Pump:Ocean Carbon Cycling and Oxygenation in Warm Climates
!
0
0
0
04 4
4
4
4
8
8
812
12
12
16
16
16
20
20
−20
−20−16
−16
−16−12
−12
−12−8
−8
−8
−8
−8
−8
−4
−4
−4
−4
−4
−40
0
0
0
0 30 60 90-30-60-90
De
pth
(km
)
0
4
2
5
1
3
S
-180 -120 -60 60-90
0
90
0 120 180
N
-1D
isso
lve
d o
xyg
en
(m
mo
l kg
)
0
50
100
150
200
250
x16 CO @ 10,000 yrs2
(started from end of the x4 simulation)
Benthic [O ]2
Evolution of the Biological Pump:Ocean Carbon Cycling and Oxygenation in Warm Climates
!
0
0
5
5
5
10
1015 152025
0
De
pth
(km
)
0
4
2
5
1
3
30 60 90-30-60-90
Temperature (°C)
0 30
Temperature (°C)0 30
15
1520 2025 2530
De
pth
(km
)
0
4
2
5
1
3
180 W°
x4 CO 2
Maastrichtian reference simulation
Evolution of the Biological Pump:Ocean Carbon Cycling and Oxygenation in Warm Climates
x1 CO pre-2
industrial reference simulation
180 W°
!
0
0
0
0
0
04
4
4
48
8
81212
12
16
16
20
−20
−20
−16
−16−12
−12−8
−8
−4
−4
−40
0
0
0
0
0
0
0 30 60 90-30-60-90
-1D
isso
lve
d o
xyg
en
(m
mo
l kg
)
De
pth
(km
)
0
4
2
5
1
3
S
-180 -120 -60 60-90
0
90
0 120 180
0
N
50
100
150
200
250
x16 CO @ 2,000 yrs2
transient state(incomplete adjustment to increased radiative forcing)
Benthic [O ]2
Evolution of the Biological Pump:Ocean Carbon Cycling and Oxygenation in Warm Climates
!
Oce
an d
epth
(km
)
5
4
3
2
1
0
13d C (‰)DIC
0.0-1.0 1.0 2.0 3.0
-90
0
90
100-260
13Open ocean d C adjacent to DIC
modern Tanzania
yellow == 13
observed d CDIC
blue == 13model d CDIC
(year 1994)
‘Suess Effect’
!
Oce
an d
epth
(km
)
5
4
3
2
1
0
13d C (‰)DIC
0.0-1.0 1.0 2.0 3.0
-90
0
90
100-260
13Open ocean d C adjacent to DIC
modern Tanzania
5
4
3
2
1
0
13d C (‰)DIC
0.0-1.0 1.0 2.0 3.0
0-90
0
90
180-180
13Planktic foraminiferal d C from early Eocene Tanzania
yellow == 13foraminiferal d C
18d O has been convertedinto pale temperature and then to habitat depth using a coupled GCM
Oce
an d
epth
(km
)
5
4
3
2
1
0
13d C (‰)DIC
0.0-1.0 1.0 2.0 3.0
-90
0
90
100-260
13Open ocean d C adjacent to DIC
modern Tanzania
5
4
3
2
1
0
13d C (‰)DIC
0.0-1.0 1.0 2.0 3.0
0-90
0
90
180-180
13Planktic foraminiferal d C from early Eocene Tanzania
blue == 13model d CDIC
(Eocene config)
!
MesoproterozoicNeoproterozoic
Phanerozoic
Cm
EraEon Proterozoic Archean
Paleoproterozoic
Phanerozoic
Cenozoic Mesozoic Paleozoic
KPgNg J T P C D OPeriod
200015001000500 2500 3000 35004003002001000Time (Ma)
Evolution of the Biological Pump:Dissolved organic matter
Evolution of the Biological Pump:Dissolved organic matter
deepocean
surfaceocean
RDOC [630 PgC]
RDOCcreation
scavengingTe
rre
str
ial
DO
C i
np
ut
(?)
UV creation/destruction
SLDOC [6]
SRDOC [14]
60° S
Pacific Ocean
60° S
40° S
40° N
60° N
Atlantic
Ocean
0
200
400
1,000
2,000
3,000
4,000
5,000
6,000
20° S
20° N
0°
40° S 20° S 0° 20° N 40° N 60° N
20° N
IndianOcean
0
200
400
1,0002,0003,0004,0005,0006,000
0
200
400
1,000
2,000
3,000
Depth (m
)
4,000
5,000
6,000
0°
40 50 60 70 80–1DOC (µmol kg )
Hansell [2012]
MesoproterozoicNeoproterozoic
Phanerozoic
Cm
EraEon Proterozoic Archean
Paleoproterozoic
Phanerozoic
Cenozoic Mesozoic Paleozoic
KPgNg J T P C D OPeriod
200015001000500 2500 3000 35004003002001000Time (Ma)
50
50 50
100
100
100 100
150150
150
150
200
200 200250 250
300
50
50 50
100
100
100 100
150150
150
150
200
200 200250 250
300
0 30 60 90-30-60-90
-1Dissolved oxygen (mmol kg )
0 300
De
pth
(km
)
0
4
2
5
1
3
Modern Pacific (zonal mean)
0 30 60 90-30-60-90
-1Dissolved oxygen (mmol kg )
0 300
-1Dissolved H S (mmol kg )2
300 0
==?
High atmospheric pO2 Low atmospheric pO2
Evolution of the Biological Pump:Dissolved organic matter
200015001000500 2500 3000 35004003002001000-15
-10
-5
0
+5
+10
+15
-1.0
+0.0
+1.0
+2.0
+3.0
+4.0
53.0 54.0 55.0 56.0 57.0 58.0
500 550 600 650 700 750Time (Ma)
Time (Ma)
-15
-10
-5
0
+5
+10
+15
13
dC
(‰
)
13
dC
(‰
)Mesoproterozoic
Neoproterozoic
Phanerozoic
Cm
EraEon Proterozoic Archean
Paleoproterozoic
Phanerozoic
Cenozoic Mesozoic Paleozoic
KPgNg J T P C D OPeriod
200015001000500 2500 3000 35004003002001000
Time (Ma)
Ridgwell and Arndt [submitted]
13d C (‰)
To
tal carb
on
rele
ase (
Pg
C)
0
2,000
0 -10 -20 -40 -60-30 -50
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
20,000
mantle CO2 @ -6‰
marine organic matter
thermogenic methane
biogenic methane
13
+6‰
dC
ini
13
-2‰
dC
ini
terrestrial:C3 plants
terrestrial:C4 plants
A DOC-dominated carbon cycle?
Contours of carbon release vs. source isotopic signature for a global -4‰ carbon isotopic excursion. Contours differ according to the initial mean
13global d C.
Ridgwell and Arndt [submitted]
deepocean
surfaceocean
RDOC [630 PgC]
RDOCcreation
scavenging
Te
rre
stria
l DO
C in
pu
t (?
)
UV creation/destruction
SLDOC [6]
SRDOC [14]
RDOC [1,630,000 PgC]
A DOC-dominated carbon cycle?
Ridgwell and Arndt [submitted]
In the Rothman et al. [2003] model, the RDOC reservoir is assumed to have been at least 10 times the size of the inorganic (ocean DIC + atmospheric pCO ) 2
reservoir. For a modern DIC + pCO2 reservoir of 39,000 PgC, this mean 390,000 PgC of DOC – more than 500 times larger than modern). For a higher late Precambrian DIC reservoir, the minimum
6DOC reservoir becomes 1.6´10 PgC, equivalent to concentration of a little over 1000 mgC per L of seawater and becoming the third most dominant
-dissolved species in the ocean after Cl .
60° S
Pacific Ocean
60° S
40° S
40° N
60° N
Atlantic
Ocean
0
200
400
1,000
2,000
3,000
4,000
5,000
6,000
20° S
20° N
0°
40° S 20° S 0° 20° N 40° N 60° N
20° N
IndianOcean
0
200
400
1,0002,0003,0004,0005,0006,000
0
200
400
1,000
2,000
3,000
Depth (m
)
4,000
5,000
6,000
0°
40 50 60 70 80–1DOC (µmol kg )
200015001000500 2500 3000 35004003002001000-15
-10
-5
0
+5
+10
+15
-1.0
+0.0
+1.0
+2.0
+3.0
+4.0
53.0 54.0 55.0 56.0 57.0 58.0
500 550 600 650 700 750Time (Ma)
Time (Ma)
-15
-10
-5
0
+5
+10
+15
13
dC
(‰
)
13
dC
(‰
)Mesoproterozoic
Neoproterozoic
Phanerozoic
Cm
EraEon Proterozoic Archean
Paleoproterozoic
Phanerozoic
Cenozoic Mesozoic Paleozoic
KPgNg J T P C D OPeriod
200015001000500 2500 3000 35004003002001000
Time (Ma)
?
Ridgwell and Arndt [submitted]
0
0 0
0
0
0
0
0
0
102030
−40
−30
−30
−20
−20
−20
−20−10
−10
−10
−10
0
0 0
0
0
0
0
0
0
0
De
pth
(km
)
0
4
2
5
1
3
30 60 90-30-60-90
-1Dissolved oxygen (mmol kg )
0 300
deepocean
surfaceocean
DOCDOC
DOCDOC
DOC
DOC
DOC
RDOCcreation
scavenging
A DOC-dominated carbon cycle?
Sexton et al. [2011]
Eocene (@180 W)°
UV creation/destruction
In the Eocene hyperthermal RDOC hypothesis, difficulties include envisioning a sufficiently stratified deep ocean (even when ignoring the lack of any evidence for widespread anoxia) that could partition RDOC away from the upper ocean and destruction by oxidation/photo-dedregation.
Thanks to:
Jamie Wilson & Steve Barker,Eleanor John, Paul Pearson [Cardiff]Sandra Arndt, Daniela Schmidt [Bristol]
Ellen Thomas [Yale]
The Royal Society, Natural Environmental Research Council, EU ERC