Outgassing of modern volcanos

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Outgassing of Modern VolcanosEarly atmosphere
was probably similar, and any oxygen was
outgassed was likely lost because it oxidized
reduced chemicals in the environment
From W. H. Schlesinger, Biogeochmistry 1997
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Aquifex
Basically a thermophillic anaerobe (90oC) Uses H2
as e- donor Can fix CO2
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Modern stromatolites (petrified microbial mats)
Fossilized stromatolites (1.8 billion years old
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Modern, freshwater, stromatolites
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Fossil stromatolite from Strelley Pool Chert 3.5
BYA
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Cyanobacterial fossils
3.5 billion year old filamentous prokaryote from
western Australia
1.0 billion year old filamentous prokaryote from
central Australia
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Microfossils and modern equivalents
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rRNA tree of life
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Carbon depletion--evidence of biology
-20 ?13C deficit of 20 parts in 1000 of 13C
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Banded Iron Formations
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Metabolic lifestyles in Archaean waters
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Time Line
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Evolution of eukaryotes
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rRNA tree of life
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rRNA tree of life
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rRNA tree of life