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Cold climate produced by algae contributed to onset of multicellular life
February 14, 2007The rise of multicellular animals about 540 million years ago was a turning point in the history of life
The rise of multicellular animals about 540 million years ago was a turning point in the history of life. A group of Finnish scientists suggests a new climate-biosphere interaction mechanism for the underlying processes in a new study, which will be published on February 14, 2007 in PLoS ONE, the international, peer-reviewed, open-access, online publication from the Public Library of Science (PLoS).
The theory invokes cold, ice-containing climates as a key precursor for multicellular life. If the model turns out to be correct, one can assume that complex life might exist also around stars which are more massive and short-lived than the Sun. Since remote sensing of highly reflecting glaciers should be possible, this may help designing future astronomical observation programmes for earthlike extrasolar planets.
Multicellular life was preceded by the cold Neoproterozoic climate 600-800 million years ago which at times produced widespread glaciations. According to the new theory, the coldness was due to low carbon dioxide concentration brought about by strong algal growth in the oceans. The algal growth was maintained by the lack of grazing animals and the ability of cold seawater to mix and transport nutrients efficiently. A moderately high seawater oxygen concentration developed as a byproduct of the algal growth. This enabled diffusive breathing of primitive multicellulars which were larger than their unicellular counterparts. The ability of cold water to contain more dissolved oxygen also helped the multicellulars to thrive.
The diversification of the marine food webs introduced by multicellular predators as well as the moving and burrowing activity of animals on the seafloor contributed to a more efficient decomposition of the algae-produced organic carbon, which slowed the rate of organic carbon sequestration. This in turn increased the atmospheric carbon dioxide level and ended the severe glaciations and the reign of unicellular algae, initiating the development of a modern-type climate.
Public Library of Science
Multicellular life was preceded by the cold Neoproterozoic climate 600-800 million years ago which at times produced widespread glaciations. According to the new theory, the coldness was due to low carbon dioxide concentration brought about by strong algal growth in the oceans. The algal growth was maintained by the lack of grazing animals and the ability of cold seawater to mix and transport nutrients efficiently. A moderately high seawater oxygen concentration developed as a byproduct of the algal growth. This enabled diffusive breathing of primitive multicellulars which were larger than their unicellular counterparts. The ability of cold water to contain more dissolved oxygen also helped the multicellulars to thrive.
The diversification of the marine food webs introduced by multicellular predators as well as the moving and burrowing activity of animals on the seafloor contributed to a more efficient decomposition of the algae-produced organic carbon, which slowed the rate of organic carbon sequestration. This in turn increased the atmospheric carbon dioxide level and ended the severe glaciations and the reign of unicellular algae, initiating the development of a modern-type climate.
Public Library of Science
Algae News and Current Algae Events RSSNew research challenges long-held assumptions of flightless bird evolution
Large flightless birds of the southern continents - African ostriches, Australian emus and cassowaries, South American rheas and the New Zealand kiwi - do not share a common flightless ancestor as once believed.
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Shipwrecks on coral reefs harbor unwanted species
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Duke chemists synthesize promising anti-cancer product
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Study shows continued spread of 'dead zones'
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Successful series of measurements in Arctic sea ice
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Key to virulence protein entry into host cells discovered
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New indicator uncovered that can predict coral health
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NOAA and Louisiana scientists predict largest Gulf of Mexico 'dead zone' on record
NOAA-supported scientists from the Louisiana Universities Marine Consortium and Louisiana State University are forecasting that the "dead zone" off the coast of Louisiana and Texas in the Gulf of Mexico this summer could be the largest on record.
Duckweed genome sequencing has global implications
Three plant biologists at Rutgers' Waksman Institute of Microbiology are obsessed with duckweed, a tiny aquatic plant with an unassuming name. Now they have convinced the federal government to focus its attention on duckweed's tremendous potential for cleaning up pollution, combating global warming and feeding the world.
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