ENVIRONMENTAL REDOX AND
PHOTOSYNTHESIS
Concepts: Biogeochemical gradients according to the electron
tower, redox calculations, anaerobic metabolisms,
photosynthetic electron donors, anoxygenic and oxygenic
photosynthesis, electron transport in photosynthetic
organisms, photosynthetic pigments and reaction centers,
geological record of oxygenic and anoxygenic photosynthesis.
1
pe
Adapted from The
Carl Sagan Lecture
By Joe Kirschvink
pe0
P680+
P680*
CH2O
CO2
–10 CO2
+
H2S
2+
Fe
0
H
H2
+
N2 NH4
CO2 CH4
S
H2S
2–
SO42–
SO4
Fe(OH)3
CH2O
+
H2
H
+
NH4
N2
CH4 CO2
H2S S
0
-
H2S
2+
Fe(OH)3
Fe
OXIDATION
+
–
NO3
NO3
NO2
Mn2+
CO
NO3
MnO2
CO2
NO2
NO3
MnO2
Mn2+
CO2 CO
N2 NO3–
H2O O2
NH4
–
+10
–
NO3
O2
+
P680
2
+
NH4
N2
H2O
P680
Courtesy of Joe Kirschvink. Used with permission.
+
The electron tower generally explains porewater chemistry
Lake Michigan Sediment
3
Black Sea
Example of an anaerobic metabolism: Microbial growth in Mono Lake, CA
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license. For more information, see http://ocw.mit.edu/help/faq-fair-use/.
4
Image courtesy of USGS.
5
6
Image courtesy of State of California.
This table has been removed due to copyright restrictions. Please see Table 3B-2 on page
http://www.monobasinresearch.org/images/mbeir/dchapter3/table3b-2.pdf.
7
This image has been removed due to copyright restrictions. Please see Figure 3 (a)
on page http://onlinelibrary.wiley.com/doi/10.1016/j.femsec.2003.12.016/full.
8
(Oremland et al., 2000)
These images have been removed due to copyright restrictions. Please see Figure 3 (b) and (c)
on page http://onlinelibrary.wiley.com/doi/10.1016/j.femsec.2003.12.016/full.
9
(Oremland et al., 2000)
2Lactate +2HAsO4 + H+
Acetate- +HCO3- +2H2AsO3(∆G’0 = -156.8 kJ mol-1).
Image by MIT OpenCourseWare.
10
(Oremland et al., 2004)
This table has been removed due to copyright restrictions. Please see Table 2 on
page http://onlinelibrary.wiley.com/doi/10.1016/j.femsec.2003.12.016/full.
11
(Oremland et al., 2004)
THERE IS ~10,000 TIMES MORE SOLAR POWER THAN ALL OTHER SOURCES
12
pe
Adapted from The
Carl Sagan Lecture
By Joe Kirschvink
pe0
P680+
P680*
CH2O
CO2
–10 CO2
+
H2S
2+
Fe
0
H
H2
+
N2 NH4
CO2 CH4
S
H2S
2–
SO42–
SO4
Fe(OH)3
CH2O
+
H2
H
+
N2
NH4
CH4 CO2
H2S S
0
-
H2S
2+
Fe(OH)3
Fe
OXIDATION
+
–
NO3
NO3
NO2
Mn2+
CO
NO3
MnO2
CO2
NO2
NO3
MnO2
Mn2+
CO2 CO
N2 NO3–
H2O O2
NH4
–
+10
–
NO3
O2
+
P680
13
+
NH4
N2
H2O
P680
Courtesy of Joe Kirschvink. Used with permission.
+
Image by MIT OpenCourseWare.
This image has been removed due to copyright restrictions. Please see
the image on page http://en.academic.ru/dic.nsf/enwiki/365148.
Image by MIT OpenCourseWare.
H2O + CO2 CH2O + O2
14
Image by MIT OpenCourseWare.
This image has been removed due to copyright restrictions. Please see
the image on page http://www.rsc.org/chemistryworld/Issues/2007/
May/PhotosynthesisWorksQuantumComputing.asp.
H2A + CO2 CH2O + A
A = Fe2+, H2, S, H2S, …
15
pe
Adapted from The
Carl Sagan Lecture
By Joe Kirschvink
pe0
P680+
P680*
CH2O
CO2
–10 CO2
+
2+
Fe
SO42–
SO4
Fe(OH)3
0
H
H2
+
N2 NH4
CO2 CH4
S
H2S
2–
H2S
CH2O
+
H2
H
+
NH4
N2
CH4 CO2
H2S S
0
-
H2S
2+
Fe(OH)3
Fe
OXIDATION
+
–
NO3
NO3
NO2
Mn2+
CO
NO3
MnO2
CO2
NO2
NO3
MnO2
Mn2+
CO2 CO
N2 NO3–
H2O O2
NH4
–
+10
–
NO3
O2
+
P680
16
+
NH4
N2
H2O
P680
Courtesy of Joe Kirschvink. Used with permission.
+
Electron transport in purple bacteria
This image has been removed due to copyright restrictions. Please see the image
on page http://www.ugr.es/~eianez/Microbiologia/images/10fotanoxi.JPG.
17
PHOTOSYNTHETIC REACTION CENTER
© sources unknown. All rights reserved. This content is excluded from our Creative
Commons license. For more information, see http://ocw.mit.edu/help/faq-fair-use/.
18
Z- Scheme of electron transport in cyanobacteria
and green plants
This image has been removed due to copyright restrictions. Please see the image on page
http://biochimej.univangers.fr/Page2/COURS/Zsuite/2Photosynthese/6SchemaZ/3Figures/2SchemaZHorton.gif.
19
This image has been removed due to copyright restrictions. Please see the image on page
http://biology200.gsu.edu/houghton/2107%20'13/Figures/Chapter8/figure8.14.jpg.
20
MAJOR PHOTOSYNTHETIC PIGMENTS
BACTERIOCHLOROPHYLL A
Anoxygenic
21
CHLOROPHYLL A
Oxygenic
Progressive evolution of tetrapyrole ring system for
higher energy, lower λ excitation
Chemical structures of (a) bacteriochlorophyll a and (b) chlorophyll a. Differences in the structures are shown in red.
Chemical structures of (c) 3-acetyl-chlorophyll a and (d) chlorophyll d. R is the phytyl tail.
22
Phylogeny of bch and chl genes
© sources unknown. All rights reserved. This content is excluded from our Creative
Commons license. For more information, see http://ocw.mit.edu/help/faq-fair-use/.
23
Increasing
excitation energy
and yield
Ancestral
Purple
Bacterium
Fe 2+
or S2-
Fe 3+
or S0
Evolving pigment and redox components
Incorporated
from a Green SBacterium ??
© 1998 Elsevier Science Ltd. All rights reserved. This content is excluded from our Creative
Commons license. For more information, see http://ocw.mit.edu/help/faq-fair-use/.
24
Evolutionary stages of oxygen evolution capacity (OEC). Four stages are depicted, although additional
intermediate stages undoubtedly also existed. For each stage, the upper diagram shows an energetic
picture, and the lower diagram a schematic of the reaction center protein in the photosynthetic
membrane.
4500
4000
2500
O2
25
500 million years
KARIJINI NATIONAL PARK –WESTERN AUSTRALIA
26
BANDED IRON
27
This image has been removed due to copyright restrictions. Please see the photo of rock in paper below.
Mojzsis, Stephen James, Gustaf Arrhenius, et al. "Evidence for Life on Earth Before 3,800
Million Years Ago." Nature 384, no. 6604 (1996): 55-9.
28
Precambrian Banded Iron Formations (BIFs)
Abundance of BIF Relative
to Hamersly Group as Max.
(Adapted from Klein & Beukes, 1992)
Canadian Greenstone Belts & Hamersley, W. Australia
Yilgaran Block, W. Australia
Transvaal, S. Africa
Paleoproterozoic (Huronian) Snowball Earth
Lake Superior, USA
Neoproterozoic
Krivoy Rog, Russia
Snowball Earths
Labrador, Canada
Rapitan, Canada
Urucum, Brazil
Damara, Namibia
Pongola Glaciation, Swaziland
(snowball??)
Zimbabwe, Ukraine,
Venezuela, W. Australia
Isua, West
Greenland
4.0
3.5
3.0
2.5
2.0
1.5
Time Before Present (Billion Years)
Courtesy of Joe Kirschvink. Used with permission.
29
1.0
0.5
0
Red beds
Photos: Kansas Geological Survey
30
Paleosols
This image has been removed due to copyright restrictions. Please see the image
on http://www.gly.uga.edu/railsback/FieldImages/BadlandsPaleosol.jpeg.
This image has been removed due to copyright restrictions. Please see the image on
http://www.gly.uga.edu/railsback/FieldImages/OrgeonBasaltPaleosol1.jpeg.
31
Image by MIT OpenCourseWare.
Fe2+
Fe2+ + CO2 CH2O + 4FeOOH
Photic zone
Fe2+
(Canfield et al. 2006, Kharecha et al. 2005, Kappler et al. 2005)
32
Image by MIT OpenCourseWare.
H2O + CO2 CH2O + O2
33
Photic zone
4500
4000
2500
500 million years
O2
Image by MIT OpenCourseWare.
This image has been removed due to copyright restrictions. Please see
the image on page http://en.academic.ru/dic.nsf/enwiki/365148.
34
CHLOROPHYLL-C PLANKTON
DIATOMS
This image has been removed due to copyright restrictions. Please see the
image on http://m.harunyahya.com/Image/guncelyorumlar/diatomm1.jpg.
35
COCCOLITHOPHORIDS
This image has been removed due to copyright restrictions. Please see
the image on http://www.boostdam.net/SIO/coccolithophorids.jpg.
MIT OpenCourseWare
http://ocw.mit.edu
12.007 Geobiology
Spring 2013
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