+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Timing of morphological and ecological innovations in the cyanobacteria--a key to understanding the rise in atmospheric oxygen

Timing of morphological and ecological innovations in the cyanobacteria--a key to understanding the rise in atmospheric oxygen

Geobiology 8(1): 1-23

When cyanobacteria originated and diversified, and what their ancient traits were, remain critical unresolved problems. Here, we used a phylogenomic approach to construct a well-resolved 'core' cyanobacterial tree. The branching positions of four lineages (Thermosynechococcus elongatus, Synechococcus elongatus, Synechococcus PCC 7335 and Acaryochloris marina) were problematic, probably due to long branch attraction artifacts. A consensus genomic tree was used to study trait evolution using ancestral state reconstruction (ASR). The early cyanobacteria were probably unicellular, freshwater, had small cell diameters, and lacked the traits to form thick microbial mats. Relaxed molecular clock analyses suggested that early cyanobacterial lineages were restricted to freshwater ecosystems until at least 2.4 Ga, before diversifying into coastal brackish and marine environments. The resultant increases in niche space and nutrient availability, and consequent sedimentation of organic carbon into the deep oceans, would have generated large pulses of oxygen into the biosphere, possibly explaining why oxygen rose so rapidly. Rapid atmospheric oxidation could have destroyed the methane-driven greenhouse with simultaneous drawdown in pCO(2), precipitating 'Snowball Earth' conditions. The traits associated with the formation of thick, laminated microbial mats (large cell diameters, filamentous growth, sheaths, motility and nitrogen fixation) were not seen until after diversification of the LPP, SPM and PNT clades, after 2.32 Ga. The appearance of these traits overlaps with a global carbon isotopic excursion between 2.2 and 2.1 Ga. Thus, a massive re-ordering of biogeochemical cycles caused by the appearance of complex laminated microbial communities in marine environments may have caused this excursion. Finally, we show that ASR may provide an explanation for why cyanobacterial microfossils have not been observed until after 2.0 Ga, and make suggestions for how future paleobiological searches for early cyanobacteria might proceed. In summary, key evolutionary events in the microbial world may have triggered some of the key geologic upheavals on the Paleoproterozoic Earth.

Please choose payment method:

(PDF emailed within 0-6 h: $19.90)

Accession: 056589264

Download citation: RISBibTeXText

PMID: 19863595

DOI: 10.1111/j.1472-4669.2009.00220.x

Related references

Secular rise of biotic soils and detrital clay minerals as a control of organic carbon burial and the rise of atmospheric oxygen in the late Precambrian. Abstracts with Programs - Geological Society of America 36(5): 403, 2004

Oxygen and animal evolution: did a rise of atmospheric oxygen "trigger" the origin of animals?. Bioessays 36(12): 1145-1155, 2014

Improved understanding of atmospheric organic aerosols via innovations in soft ionization aerosol mass spectrometry. Analytical Chemistry 83(7): 2409-2415, 2011

Modeling the rise of atmospheric oxygen. Eos, Transactions, American Geophysical Union 85(47, Suppl, 2004

Atmospheric evolution; the rise of oxygen. Pages 159-163:, 1992

Plume activity and the rise of atmospheric oxygen. Abstracts with Programs - Geological Society of America 32(7): 315, 2000

Supercontinents, supermountains and the rise of atmospheric oxygen. Geological Society of Australia 89: 62, 2008

Evidence for a dramatic rise in atmospheric oxygen between 2.2 and 1.9 b.y.b.p. Abstracts with Programs - Geological Society of America 21(6): 24, 1989

Earth history. The rise of atmospheric oxygen. Science 293(5531): 819-820, 2001

Sulfate, methane, and the rise in atmospheric oxygen. Geochimica et Cosmochimica Acta 71(15S): A176, 2007

Carbon isotopes and the rise of atmospheric oxygen. Geology 24(10): 867-870, 1996

Biogeochemical modelling of the rise in atmospheric oxygen. Geobiology 4(4): 239-269, 2006

Anaerobic methanotrophy and the rise of atmospheric oxygen. Philosophical Transactions. Series A Mathematical Physical and Engineering Sciences 365(1856): 1867-1888, 2007

Rise of atmospheric oxygen and the upside-down Archean mantle. Geochemistry, Geophysics, Geosystems 2(1), 2001

Search for new clues for the early rise of atmospheric oxygen. West Australian Geologist 386: 1-3, 1999