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The paleobiological record of photosynthesis.

William Schopf J - Photosyn. Res. (2010)

Bottom Line: Fossil evidence of photosynthesis, documented in Precambrian sediments by microbially laminated stromatolites, cyanobacterial microscopic fossils, and carbon isotopic data consistent with the presence of Rubisco-mediated CO2-fixation, extends from the present to ~3,500 million years ago.Such data, however, do not resolve time of origin of O2-producing photoautotrophy from its anoxygenic, bacterial, evolutionary precursor.Though it is well established that Earth's ecosystem has been based on autotrophy since its very early stages, the time of origin of oxygenic photosynthesis, more than 2,450 million years ago, has yet to be established.

View Article: PubMed Central - PubMed

Affiliation: Department of Earth and Space Sciences, Institute of Geophysics and Planetary Physics, Center for the Study of Evolution and the Origin of Life, and Molecular Biology Institute, University of California, Los Angeles, 90095, USA. schopf@ess.ucla.edu

ABSTRACT
Fossil evidence of photosynthesis, documented in Precambrian sediments by microbially laminated stromatolites, cyanobacterial microscopic fossils, and carbon isotopic data consistent with the presence of Rubisco-mediated CO2-fixation, extends from the present to ~3,500 million years ago. Such data, however, do not resolve time of origin of O2-producing photoautotrophy from its anoxygenic, bacterial, evolutionary precursor. Though it is well established that Earth's ecosystem has been based on autotrophy since its very early stages, the time of origin of oxygenic photosynthesis, more than 2,450 million years ago, has yet to be established.

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Fossil oscillatoriacean cyanobacteria (a through f) in petrographic thin sections of stromatolitic chert from the ~850-Ma-old Bitter Springs Formation of central Australia; modern oscillatoriaceans (g and h) compared with a morphologically similar fossil trichome (i through q) in a thin section of a cherty stromatolite from the ~775 Ma-old Chichkan Formation of southern Kazakhstan; and pustular laminae, formed by colonies of entophysalidacean cyanobacteria, in a thin section of stromatolitic chert from the ~2,100-Ma-old Kasegalik Formation of the Belcher Islands, Canada. a, b Optical montage (a), composed of five photomicrographs (denoted by the white lines), and a CLSM image (b) of Heliconema, a spirally coiled oscillatoriacean similar to modern Spirulina. c–f Optical montage (c), composed of ten photomicrographs (denoted by the white lines), and CLSM (d and e) and a 3-D Raman image (f) of a large-celled specimen of Cephalophytarion that descends from where it transects the upper surface of the thin section (at the far right) to a depth of 20 μm (at the far left); the larger red rectangle in c denotes the area shown in e, whereas the smaller rectangle denotes the area shown in f; unlike the composite optical image (c), which shows only the medial plane of the specimen, the CLSM image (d) shows its true 3-D morphology; the 3-D Raman image of its end cells (f), rotated to show the flat uppermost surface of the cells where they transect the thin section surface, demonstrates that the kerogenous cell walls (gray) enclose quartz-filled cell lumina (white). g, h Optical images of two specimens of modern Oscillatoria sp. showing the rounded terminal cells (left), disk-shaped medial cells, and partial septations (arrows) characteristic of oscillatoriacean cyanobacteria. i Optical image of the fossil oscillatoriacean, Oscillatoriopsis media, descending into a thin section at a low angle from left to right, shown in a photomontage in which the red rectangles denote the areas of the trichome shown in CLSM images (j through n) and 3-D Raman images (o through q). j The trichome terminus, showing its rounded end-cell and subtending disk-shaped medial cells. k A part of the trichome situated ~14 μm deeper in the section than the trichome terminus (and ~28 μm below the upper surface of the section) that exhibits partial septations (arrows) like those shown in g and h. l–n A deeper part of the trichome (~39 μm below the upper surface of the section) that similarly exhibits partial septations (arrows), in l and m showing the specimen as viewed from above its upper surface (the same perspective as shown in i, but in m with the trichome tilted slightly to the right to show its interior) and in n showing the trichome as viewed from its side. o–q 3-D Raman images (acquired in a spectral window centered in the kerogen “G” band at ~1605 cm−1) showing the kerogenous composition of the trichome and its partial septations: o, the part of specimen denoted by the red rectangle in l, as viewed from above the trichome; p, the part denoted in m, titled slightly to the left; q, the part denoted in n, showing the specimen from its side. r A low-magnification optical image of stromatolitic laminae formed by laterally interlinked colonies (at arrows) of the entophysalidacean cyanobacterium Eoentophysalis
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Fig4: Fossil oscillatoriacean cyanobacteria (a through f) in petrographic thin sections of stromatolitic chert from the ~850-Ma-old Bitter Springs Formation of central Australia; modern oscillatoriaceans (g and h) compared with a morphologically similar fossil trichome (i through q) in a thin section of a cherty stromatolite from the ~775 Ma-old Chichkan Formation of southern Kazakhstan; and pustular laminae, formed by colonies of entophysalidacean cyanobacteria, in a thin section of stromatolitic chert from the ~2,100-Ma-old Kasegalik Formation of the Belcher Islands, Canada. a, b Optical montage (a), composed of five photomicrographs (denoted by the white lines), and a CLSM image (b) of Heliconema, a spirally coiled oscillatoriacean similar to modern Spirulina. c–f Optical montage (c), composed of ten photomicrographs (denoted by the white lines), and CLSM (d and e) and a 3-D Raman image (f) of a large-celled specimen of Cephalophytarion that descends from where it transects the upper surface of the thin section (at the far right) to a depth of 20 μm (at the far left); the larger red rectangle in c denotes the area shown in e, whereas the smaller rectangle denotes the area shown in f; unlike the composite optical image (c), which shows only the medial plane of the specimen, the CLSM image (d) shows its true 3-D morphology; the 3-D Raman image of its end cells (f), rotated to show the flat uppermost surface of the cells where they transect the thin section surface, demonstrates that the kerogenous cell walls (gray) enclose quartz-filled cell lumina (white). g, h Optical images of two specimens of modern Oscillatoria sp. showing the rounded terminal cells (left), disk-shaped medial cells, and partial septations (arrows) characteristic of oscillatoriacean cyanobacteria. i Optical image of the fossil oscillatoriacean, Oscillatoriopsis media, descending into a thin section at a low angle from left to right, shown in a photomontage in which the red rectangles denote the areas of the trichome shown in CLSM images (j through n) and 3-D Raman images (o through q). j The trichome terminus, showing its rounded end-cell and subtending disk-shaped medial cells. k A part of the trichome situated ~14 μm deeper in the section than the trichome terminus (and ~28 μm below the upper surface of the section) that exhibits partial septations (arrows) like those shown in g and h. l–n A deeper part of the trichome (~39 μm below the upper surface of the section) that similarly exhibits partial septations (arrows), in l and m showing the specimen as viewed from above its upper surface (the same perspective as shown in i, but in m with the trichome tilted slightly to the right to show its interior) and in n showing the trichome as viewed from its side. o–q 3-D Raman images (acquired in a spectral window centered in the kerogen “G” band at ~1605 cm−1) showing the kerogenous composition of the trichome and its partial septations: o, the part of specimen denoted by the red rectangle in l, as viewed from above the trichome; p, the part denoted in m, titled slightly to the left; q, the part denoted in n, showing the specimen from its side. r A low-magnification optical image of stromatolitic laminae formed by laterally interlinked colonies (at arrows) of the entophysalidacean cyanobacterium Eoentophysalis

Mentions: Among the several taxonomic families of filamentous cyanobacteria, stromatolite-building members of the Oscillatoriaceae have the most extensive fossil record, represented by diverse fossils in hundreds of ancient microbial communities (e.g., Fig. 4a through q). Two representative Precambrian examples, ~850 Ma in age, are shown in Fig. 4a through f: a spirally coiled specimen (Helioconema funiculum, Fig. 4a and b), similar to species of the modern oscillatoriacean genus Spirulina; and a tapering cellular trichome (Cephalophytarion laticellulosum, Fig. 4c through f) that resembles the modern cyanobacterium Oscillatoria amoenum. The organismal form and cellular structure of such specimens, traditionally illustrated by photomicrographic montages (e.g., Fig. 4a and c), can be appreciably better documented by use of confocal laser scanning microscopy (CLSM), a technique only recently introduced to Precambrian studies (Schopf et al. 2006). Compare, for example, the optical image of the spirally coiled specimen (Fig. 4a) with its CLSM image (Fig. 4b), and the optical image of the tapering trichome, artificially flattened in the photomontage (Fig. 4c), with the corresponding CLSM images (Fig. 4d and e) that show the specimen to plunge steeply into the thin rock slice (a petrographic thin section) in which it is embedded. A second newly introduced technique, Raman imagery (Schopf et al. 2005), can be used to document, in three dimensions (Schopf and Kudryavtsev 2005), the chemical composition of such rock-embedded fossils and that of their embedding matrix, for the tapering trichome, showing that the walls of its terminal cells are composed of carbonaceous kerogen and that the cells themselves are permineralized by quartz (Fig. 4f).Fig. 4


The paleobiological record of photosynthesis.

William Schopf J - Photosyn. Res. (2010)

Fossil oscillatoriacean cyanobacteria (a through f) in petrographic thin sections of stromatolitic chert from the ~850-Ma-old Bitter Springs Formation of central Australia; modern oscillatoriaceans (g and h) compared with a morphologically similar fossil trichome (i through q) in a thin section of a cherty stromatolite from the ~775 Ma-old Chichkan Formation of southern Kazakhstan; and pustular laminae, formed by colonies of entophysalidacean cyanobacteria, in a thin section of stromatolitic chert from the ~2,100-Ma-old Kasegalik Formation of the Belcher Islands, Canada. a, b Optical montage (a), composed of five photomicrographs (denoted by the white lines), and a CLSM image (b) of Heliconema, a spirally coiled oscillatoriacean similar to modern Spirulina. c–f Optical montage (c), composed of ten photomicrographs (denoted by the white lines), and CLSM (d and e) and a 3-D Raman image (f) of a large-celled specimen of Cephalophytarion that descends from where it transects the upper surface of the thin section (at the far right) to a depth of 20 μm (at the far left); the larger red rectangle in c denotes the area shown in e, whereas the smaller rectangle denotes the area shown in f; unlike the composite optical image (c), which shows only the medial plane of the specimen, the CLSM image (d) shows its true 3-D morphology; the 3-D Raman image of its end cells (f), rotated to show the flat uppermost surface of the cells where they transect the thin section surface, demonstrates that the kerogenous cell walls (gray) enclose quartz-filled cell lumina (white). g, h Optical images of two specimens of modern Oscillatoria sp. showing the rounded terminal cells (left), disk-shaped medial cells, and partial septations (arrows) characteristic of oscillatoriacean cyanobacteria. i Optical image of the fossil oscillatoriacean, Oscillatoriopsis media, descending into a thin section at a low angle from left to right, shown in a photomontage in which the red rectangles denote the areas of the trichome shown in CLSM images (j through n) and 3-D Raman images (o through q). j The trichome terminus, showing its rounded end-cell and subtending disk-shaped medial cells. k A part of the trichome situated ~14 μm deeper in the section than the trichome terminus (and ~28 μm below the upper surface of the section) that exhibits partial septations (arrows) like those shown in g and h. l–n A deeper part of the trichome (~39 μm below the upper surface of the section) that similarly exhibits partial septations (arrows), in l and m showing the specimen as viewed from above its upper surface (the same perspective as shown in i, but in m with the trichome tilted slightly to the right to show its interior) and in n showing the trichome as viewed from its side. o–q 3-D Raman images (acquired in a spectral window centered in the kerogen “G” band at ~1605 cm−1) showing the kerogenous composition of the trichome and its partial septations: o, the part of specimen denoted by the red rectangle in l, as viewed from above the trichome; p, the part denoted in m, titled slightly to the left; q, the part denoted in n, showing the specimen from its side. r A low-magnification optical image of stromatolitic laminae formed by laterally interlinked colonies (at arrows) of the entophysalidacean cyanobacterium Eoentophysalis
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Fig4: Fossil oscillatoriacean cyanobacteria (a through f) in petrographic thin sections of stromatolitic chert from the ~850-Ma-old Bitter Springs Formation of central Australia; modern oscillatoriaceans (g and h) compared with a morphologically similar fossil trichome (i through q) in a thin section of a cherty stromatolite from the ~775 Ma-old Chichkan Formation of southern Kazakhstan; and pustular laminae, formed by colonies of entophysalidacean cyanobacteria, in a thin section of stromatolitic chert from the ~2,100-Ma-old Kasegalik Formation of the Belcher Islands, Canada. a, b Optical montage (a), composed of five photomicrographs (denoted by the white lines), and a CLSM image (b) of Heliconema, a spirally coiled oscillatoriacean similar to modern Spirulina. c–f Optical montage (c), composed of ten photomicrographs (denoted by the white lines), and CLSM (d and e) and a 3-D Raman image (f) of a large-celled specimen of Cephalophytarion that descends from where it transects the upper surface of the thin section (at the far right) to a depth of 20 μm (at the far left); the larger red rectangle in c denotes the area shown in e, whereas the smaller rectangle denotes the area shown in f; unlike the composite optical image (c), which shows only the medial plane of the specimen, the CLSM image (d) shows its true 3-D morphology; the 3-D Raman image of its end cells (f), rotated to show the flat uppermost surface of the cells where they transect the thin section surface, demonstrates that the kerogenous cell walls (gray) enclose quartz-filled cell lumina (white). g, h Optical images of two specimens of modern Oscillatoria sp. showing the rounded terminal cells (left), disk-shaped medial cells, and partial septations (arrows) characteristic of oscillatoriacean cyanobacteria. i Optical image of the fossil oscillatoriacean, Oscillatoriopsis media, descending into a thin section at a low angle from left to right, shown in a photomontage in which the red rectangles denote the areas of the trichome shown in CLSM images (j through n) and 3-D Raman images (o through q). j The trichome terminus, showing its rounded end-cell and subtending disk-shaped medial cells. k A part of the trichome situated ~14 μm deeper in the section than the trichome terminus (and ~28 μm below the upper surface of the section) that exhibits partial septations (arrows) like those shown in g and h. l–n A deeper part of the trichome (~39 μm below the upper surface of the section) that similarly exhibits partial septations (arrows), in l and m showing the specimen as viewed from above its upper surface (the same perspective as shown in i, but in m with the trichome tilted slightly to the right to show its interior) and in n showing the trichome as viewed from its side. o–q 3-D Raman images (acquired in a spectral window centered in the kerogen “G” band at ~1605 cm−1) showing the kerogenous composition of the trichome and its partial septations: o, the part of specimen denoted by the red rectangle in l, as viewed from above the trichome; p, the part denoted in m, titled slightly to the left; q, the part denoted in n, showing the specimen from its side. r A low-magnification optical image of stromatolitic laminae formed by laterally interlinked colonies (at arrows) of the entophysalidacean cyanobacterium Eoentophysalis
Mentions: Among the several taxonomic families of filamentous cyanobacteria, stromatolite-building members of the Oscillatoriaceae have the most extensive fossil record, represented by diverse fossils in hundreds of ancient microbial communities (e.g., Fig. 4a through q). Two representative Precambrian examples, ~850 Ma in age, are shown in Fig. 4a through f: a spirally coiled specimen (Helioconema funiculum, Fig. 4a and b), similar to species of the modern oscillatoriacean genus Spirulina; and a tapering cellular trichome (Cephalophytarion laticellulosum, Fig. 4c through f) that resembles the modern cyanobacterium Oscillatoria amoenum. The organismal form and cellular structure of such specimens, traditionally illustrated by photomicrographic montages (e.g., Fig. 4a and c), can be appreciably better documented by use of confocal laser scanning microscopy (CLSM), a technique only recently introduced to Precambrian studies (Schopf et al. 2006). Compare, for example, the optical image of the spirally coiled specimen (Fig. 4a) with its CLSM image (Fig. 4b), and the optical image of the tapering trichome, artificially flattened in the photomontage (Fig. 4c), with the corresponding CLSM images (Fig. 4d and e) that show the specimen to plunge steeply into the thin rock slice (a petrographic thin section) in which it is embedded. A second newly introduced technique, Raman imagery (Schopf et al. 2005), can be used to document, in three dimensions (Schopf and Kudryavtsev 2005), the chemical composition of such rock-embedded fossils and that of their embedding matrix, for the tapering trichome, showing that the walls of its terminal cells are composed of carbonaceous kerogen and that the cells themselves are permineralized by quartz (Fig. 4f).Fig. 4

Bottom Line: Fossil evidence of photosynthesis, documented in Precambrian sediments by microbially laminated stromatolites, cyanobacterial microscopic fossils, and carbon isotopic data consistent with the presence of Rubisco-mediated CO2-fixation, extends from the present to ~3,500 million years ago.Such data, however, do not resolve time of origin of O2-producing photoautotrophy from its anoxygenic, bacterial, evolutionary precursor.Though it is well established that Earth's ecosystem has been based on autotrophy since its very early stages, the time of origin of oxygenic photosynthesis, more than 2,450 million years ago, has yet to be established.

View Article: PubMed Central - PubMed

Affiliation: Department of Earth and Space Sciences, Institute of Geophysics and Planetary Physics, Center for the Study of Evolution and the Origin of Life, and Molecular Biology Institute, University of California, Los Angeles, 90095, USA. schopf@ess.ucla.edu

ABSTRACT
Fossil evidence of photosynthesis, documented in Precambrian sediments by microbially laminated stromatolites, cyanobacterial microscopic fossils, and carbon isotopic data consistent with the presence of Rubisco-mediated CO2-fixation, extends from the present to ~3,500 million years ago. Such data, however, do not resolve time of origin of O2-producing photoautotrophy from its anoxygenic, bacterial, evolutionary precursor. Though it is well established that Earth's ecosystem has been based on autotrophy since its very early stages, the time of origin of oxygenic photosynthesis, more than 2,450 million years ago, has yet to be established.

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