New research deals a blow to the hypothesis that a decrease in atmospheric oxygen contributed to a mass extinction 250 million years ago.
... -old rocks in the Transvaal Supergroup in South Africa, they found evidence of a sudden increase in atmospheric oxygen that broadly coincided with physical evidence of glacial debris, and geochemical ...
... of the earth's surface. Throughout history our climate has been dependent on balance between CO2 and atmospheric oxygen. The more CO2 and other greenhouse gases, the warmer the climate has been. But ...
... their lives either as white dwarfs with very oxygen-rich cores, or undergo a supernova and collapse into ... discover two white dwarfs with large atmospheric oxygen abundances.
Lead author on the paper, ...
... molecule", oxygen, became abundant on Earth.
Andrew added: "Our understanding of the changes in atmospheric oxygen is good, but our planet is 70% covered by oceans. Determining the oceanic oxygen ...
Plate tectonics gave rise to atmospheric oxygen
... These bacteria thrived in oceans devoid of oxygen. The atmosphere also lacked oxygen then. Like today' ... transition about 540 million years ago, when atmospheric oxygen again increased notably reaching ...
... oxygen rich, Buick believes.
Geochemical examination of stratigraphic samples from the core indicates that atmospheric oxygen rose in a temporary "whiff" about 2.5 billion years ago. The whiff ...
... of complex life forms.
Konhauser says that this paper is the first to link to changes in Earth's volcanism to the microbial populations that determined the timing for the rise of atmospheric oxygen.
... of carbon-rich vegetation, seasonally dry climates, atmospheric oxygen, widespread lightning, and volcano ignitions. Yet, despite the human species' long-held appreciation of ...
... (2650-2100 million years ago), termed the Great Oxidation Event. Although the atmospheric ... rock succession, in order to reconstruct the history of atmospheric oxygenation. Time-series data for multiple ...
... fossils. The deglacial outwash formed a less dense, low¬ salinity 'lid' on the oceans preventing atmospheric oxygen penetrating to the seafloor. The absence of oxygen under such conditions served to ...
... stem cell genes OCT4, SOX2 and NANOG already in the skin cells by lowering the amount of atmospheric oxygen the cells were exposed to, and by adding a protein called fibroblast growth factor 2 (FGF2) ...
... formed in the ancient oceans, the team has found that a rise in atmospheric oxygen levels 580 million years ... years ago.
"It was not until a second rise in atmospheric oxygen 580 million years ago ...
... microbes with sulfur-based metabolisms. In addition, chemical and pH changes in the ocean and rising atmospheric oxygen may have allowed the emergence and spread of oxygen-dependent organisms.
The ...
