# Where is more oxygen? **URL:** \ **Category:** Factual Questions\ **Created:** [November 20, 2013, 10:10am UTC](https://boards.straightdope.com/t/where-is-more-oxygen/674332 "2013-11-20T10:10:26Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 21, 2013, 1:06am UTC](https://boards.straightdope.com/t/where-is-more-oxygen/674332/21 "2013-11-21T01:06:26Z")
10 meters, not 10 feet. ---
**Author:** ![Sofis](https://avatars.discourse-cdn.com/v4/letter/s/e5b9ba/32.png) [@Sofis](https://boards.straightdope.com/u/Sofis)\ **Post date:** [November 21, 2013, 2:41am UTC](https://boards.straightdope.com/t/where-is-more-oxygen/674332/22 "2013-11-21T02:41:59Z")
By the way, guys, I appear to have misread the cite I gave on the mass of atmospheric oxygen. [Here’s](http://members.shaw.ca/tfrisen/is_there_enough_oxygen.htm) a more readable one. The mass of atmospheric oxygen is actually 1.2 x 10^15 tonnes, so there is only a thousand times more in the water. That no one called me on this quite neatly illustrates how bad human intuition is at estimating these sorts of things, I think. You can be off by a factor of a million without anyone noticing. 🙂 ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [November 21, 2013, 3:15am UTC](https://boards.straightdope.com/t/where-is-more-oxygen/674332/23 "2013-11-21T03:15:44Z")
Yeah, who cares about 5 or 6 orders of magnitude, anyway? ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [November 21, 2013, 8:28am UTC](https://boards.straightdope.com/t/where-is-more-oxygen/674332/24 "2013-11-21T08:28:53Z")
> [@lazybratsche](#): > > It came from the oxygen in water, split off by plants and photosynthetic bacteria. Actually most of the oxygen in the atmosphere came from carbon dioxide. Although some water was split into hydrogen and oxygen, the hydrogen mostly recombined with atmospheric oxygen before it could reach the top of the atmosphere and escape. Carbon, in the form of organic compounds, is more persistent, and is eventually incorporated into rocks in the form of kerogen. Photosynthesis has produced more than twenty atmosphere’s worth of oxygen over the lifetime of the Earth, and the corresponding amount of carbon is buried in the crust- and so is most of the oxygen, in the form of oxidised minerals. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [November 21, 2013, 8:37am UTC](https://boards.straightdope.com/t/where-is-more-oxygen/674332/25 "2013-11-21T08:37:28Z")
> [@Jonathan\_Chance](#): > > Well, let’s throw this out there, then. > > In the past, the O2 level in the atmosphere has been up to 50% or so higher than now. Where’d that O2 come from and where’d it go? Less dissolved in the oceans? Released from melting ice? Hollowing out of the core? What? Volcanoes constantly emit carbon dioxide, and this is split into carbon and oxygen by photosynthesis. These two elements are removed by the processes of kerogen formation and oxidation of the crust. If the rate of oxygen removal is low compared to the rate of oxygen production, the atmospheric oxygen level will increase - but this will only go so far, since oxygen is a very active element, and at high levels the rate of oxidation increases considerably - sometimes, I would imagine, in the form of wildfire. ---
**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\ **Post date:** [November 21, 2013, 8:49am UTC](https://boards.straightdope.com/t/where-is-more-oxygen/674332/26 "2013-11-21T08:49:57Z")
> [@Sofis](#): > > Earth’s water masses at [1.35 x 10^18 tonnes](http://www.universetoday.com/65588/). Approximately eight ninths of that is oxygen, so 1.2 x 10^18 tonnes. > > The oxygen in the atmosphere masses at [1.2 x 10^9 tonnes](http://mathscinotes.wordpress.com/2011/04/09/oxygen-on-earth/). So there is approximately 1 000 000 000 times as much oxygen in water molecules as there is in the atmosphere. > > Given this estimate, the oxygen dissolved in water can probably be discounted as irrelevant. What about all the water vapor, and clouds, in the atmosphere? ---
**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\ **Post date:** [November 21, 2013, 9:09am UTC](https://boards.straightdope.com/t/where-is-more-oxygen/674332/27 "2013-11-21T09:09:00Z")
I read somewhere that, by volume, oxygen dominates the Earth’s crust (and mantle too, I guess), even more than it does in terms of mass or numbers of atoms. Not only is it the most common element in the crust, but, because, in the compounds it forms, its atoms are electron acceptors, such that the oxygen atoms retain and complete their outer electron shell. Thus the volume of an oxygen atom (including its electron shells) in a crustal compound is considerably greater than the volumes of the atoms of most of the other crustal elements, most of which act as electron donors and so lose their outer electron shell. Walk upon the surface of the Earth and, to a large extent, you are walking on (somewhat impure) oxygen. ---
**Author:** ![Sofis](https://avatars.discourse-cdn.com/v4/letter/s/e5b9ba/32.png) [@Sofis](https://boards.straightdope.com/u/Sofis)\ **Post date:** [November 21, 2013, 9:14am UTC](https://boards.straightdope.com/t/where-is-more-oxygen/674332/28 "2013-11-21T09:14:13Z")
> [@njtt](#): > > What about all the water vapor, and clouds, in the atmosphere? According to Wikipedia: [ > [@](#): > > The percentage water vapor in surface air varies from .01% at -42℃ (-44℉) to 4.24% when the dew point is 30℃ (86℉). ]([Water vapor - Wikipedia](http://en.wikipedia.org/wiki/Water_vapor#Water_vapor_in_Earth.27s_atmosphere)) At a few percent at most, there’s a lot less oxygen in atmospheric water vapor than there is in gaseous oxygen, so at the level of precision we’re using, it’s not going to affect the thousand to one ratio. ---
**Author:** ![Grey](https://avatars.discourse-cdn.com/v4/letter/g/b782af/32.png) [@Grey](https://boards.straightdope.com/u/Grey)\ **Post date:** [November 21, 2013, 5:28pm UTC](https://boards.straightdope.com/t/where-is-more-oxygen/674332/29 "2013-11-21T17:28:47Z")
> [@tracer](#): > > I’m guessing they meant “Percentage mass of the earth”, not “percentage mass of the earth’s core”. > > But then again, this IS a .de domain. Who knows if the people who wrote the webpage even speak English? Maybe but this wikipedia reference (^ Morgan, J. W.; Anders, E. (1980). “Chemical composition of Earth, Venus, and Mercury”. Proceedings of the National Academy of Sciences 77 (12): 6973–6977. Bibcode:1980PNAS…77.6973M. doi:10.1073/pnas.77.12.6973. PMC 350422. PMID 16592930.) says the > [@](#): > > The mass of the Earth is approximately 5.98×1024 kg. It is composed mostly of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminium (1.4%); with the remaining 1.2% consisting of trace amounts of other elements. Due to mass segregation, the core region is believed to be primarily composed of iron (88.8%), with smaller amounts of nickel (5.8%), sulfur (4.5%), and less than 1% trace elements. [Previous page](https://boards.straightdope.com/t/where-is-more-oxygen/674332.md?page=1)