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Posts Tagged ‘Daines’

Lured by the promise of posters and breakfast, I wandered down to the Ice Rink area to check out the posters this morning, and I’m glad I did, because I got to meet Stuart Daines, a postdoctoral researcher in Tim Lenton’s Earth Systems Modelling Group (http://researchpages.net/ESMG/). They have developed a model of “oxygen oases” before the Great Oxidation Event 2300 million years ago. Oxygen oases are hypothesized regions of the ocean where, due to high primary production by oxygenic phytoplankton, the ocean could have had a much higher concentration of oxygen than the ocean did on average. These oxygen oases are important for understanding the evolution of life on Earth because they were regions in which the modern ocean carbon-oxygen system probably evolved. In their box model, organic carbon is converted to CO2 and methane during methanogensis; this is starkly contrasted with our groups model, where organic matter is used to feed sulfate and ferric iron reduction. Contrasting these two systems – their methane-oxygen coastal system with our global redoxcline ocean – gives us a broader picture of the biogeochemistry of the early Earth. However, like our model, it raises more questions than it answers. For example, what impact would the Paleoproterozoic global glaciations (~2400 million years ago – Kirschvink et al., 2000) have on primary production? What was the dominant limiting factor on primary production at this time? Could the ocean even support a redoxcline globally for such a long time period? These questions will hopefully be answered not only through future modelling endeavors, but also through direct analysis of the rock record. Hopefully, some of these answers will be discussed at later sessions, such as 07c: Records of Ocean Anoxia and their Impact on Life.

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