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Thread: does our oxygen is going to end?

  1. #1 does our oxygen is going to end? 
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    read this:
    Incidentally, having said that oxygen is produced by green plants and algae, it is an oversimplification to leave it at that. It is true that plants give off oxygen. But when a plant dies, its decay, in chemical reactions equivalent to burning all its carbonaceous materials, would use up an amount of oxygen equal to all the oxygen released by that plant during its lifetime. There would therefore be no net gain in atmospheric oxygen, but for one thing. Not all dead plants decay. Some of them are laid down as coal (or equivalents), where they are removed from circulation. If all the fossil fuels of the world were burned by humanity, much of the oxygen in the atmosphere would be replaced by carbon dioxide, restoring the ancient status quo. This is not likely to happen in the near future. But we should not forget that the only reason we have oxygen to breathe is that most of the carbon of the world is tied up underground.
    (From Richard Dawkins, The Ancestor's Tale, p. 565)
    is that right? what can we do about it?


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  3. #2  
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    I don't believe this is accurate. It is true that plant decay consumes oxygen. Plants also consume oxygen at night when their respiration is proceeding but there is no photosynthesis.

    However, the decay of plants goes hand - in - hand with the growth of other organisms. Decay is a biological process, so the carbon in the plants goes to build up the living things that are consuming those plants.

    The main consideration that Dawkins seems to err on, is that if the premise regarding fossil carbon were true, oxygen never would have been able to become established in the first place. Oxygenic photosynthesis evolved on the planet under conditions of high atmospheric CO2 and no fossil fuels whatsoever.


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    Yeah, I'm not sure about this idea. The Earth's atmosphere became oxygenated 2-3 billion years ago, the simplest explanation being from autotrophic bacteria such as cynaobacteria. Clearly, an atmosphere was first established and subsequently maintained, which means that Dawkins' claim is... if not incorrect, then requires a substantial amount of contextualization.
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    I've read this is true, there was a paper about it a few years back and Oxygen has in fact dropped a bit over the past few decades. By comparison to the share volume of Oxygen, and minor amount of Co2 even if most liquid fossil fuels were burned would have little noticeable effect. I'm not as certain about coal and mythl hydrates. I'll see if I can dig something up.
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  6. #5  
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    If there has been a drop in O2 levels surely it is a result of deforestation and ocean acidification (reduced algae?) rather than fossil fuel oxidation.
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  7. #6  
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    that, I think, is a very simple minded view


    plants give off around a tonne of O2 during their lifespan they rot in around a week, if they used all that O2 in a week it would be lethal to be near a compost heap



    now even if we assume that plant's do absorb all exhumed O2 as they rot, saying trees do the same is about as stubborn as various Christians saying the world is 6000 years old even after carbon dating
    It's not how many questions you ask, but the answers you get - Booms

    This is the Acadamy of Science! we don't need to 'prove' anything!
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