Talk:Oxygen cycle

Wiki Education Foundation-supported course assignment
This article was the subject of a Wiki Education Foundation-supported course assignment, between 8 January 2019 and 23 April 2019. Further details are available on the course page. Student editor(s): Pengxiao Xu. Peer reviewers: Rotheconrad, Pengxiao Xu.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 05:58, 17 January 2022 (UTC)

Planning significant page update
I have been assigned to update and make additions to this Wikipedia page for a graduate course. The reference section is disorganized, mostly unnumbered, and links are broken or absent. The references are several decades old and we have more current data. I plan to update the data with current numbers and redo the reference section. I also plan to add historical and global context to the page as well as greater depth and more accessible explanations. If anyone has requests or trepidations please share them and I will accommodate if feasible. Rotheconrad (talk) 18:55, 15 February 2019 (UTC)

Planned References to use for page update:
Rotheconrad (talk) 21:43, 22 February 2019 (UTC)
 * 1) Petsch, Steven (2014). "The global oxygen cycle". Treatise Geochem Second Ed. 10 (2014): 437-474. https://doi.org/10.1016/B978-0-08-095975-7.00811-1
 * 2) Huang, Jianping et al.  (2018). "The global oxygen budget and its future projection." Science Bulletin. 63 (18): 1180-1186. https://doi.org/10.1016/j.scib.2018.07.023
 * 3) Boyce, Daniel G.; Lewis, Marlon R.; Worm, Boris (2010). "Global phytoplankton decline over the past century." Nature. 466 (7306): 591-596. https://doi.org/10.1038/nature09268
 * 4) Behrenfeld, Michael J. et al.  (2006)l. "Climate-driven trends in contemporary ocean productivity." Nature. 444 (7120): 752-755. https://doi.org/10.1038/nature05317
 * 5) Lenton, Timothy M.; Watson, Andrew J. (2000). "Redfield revisited: 2. What regulates the oxygen content of the atmosphere?." Global Biogeochemical Cycles. 14 (1): 249-268. https://doi.org/10.1029/1999GB900076
 * 6) Resplandy, L. et al.  (2018). "Quantification of ocean heat uptake from changes in atmospheric O 2 and CO 2 composition." Nature. 563 (7729): 105-108. https://doi.org/10.1038/s41586-018-0651-8
 * Hu, Qingyang, et al. (2016). "FeO 2 and FeOOH under deep lower-mantle conditions and Earth’s oxygen–hydrogen cycles." Nature. 534 (7606): 241-244. https://doi.org/10.1038/nature18018
 * 1) Falkowski, Paul G.  (2011). "The biological and geological contingencies for the rise of oxygen on Earth." Photosynth Res. 107 (1): 7-10. https://doi.org/10.1007/s11120-010-9602-4
 * 2) Falkowski, Paul G.; Godfrey, Linda V. (2008). "Electrons, life and the evolution of Earth's oxygen cycle." Philosophical Transactions of the Royal Society B: Biological Sciences. 363 (1504): 2705-2716. https://doi.org/10.1098/rstb.2008.0054
 * 3) Keeling, Ralph F.; Körtzinger, Arne; Gruber, Nicolas (2010). "Ocean deoxygenation in a warming world". Annual Review of Marine Science. 2 (2010): 199-229. https://doi.org/10.1146/annurev.marine.010908.163855
 * 4) Holland, Heinrich D. (2006). "The oxygenation of the atmosphere and oceans." Philosophical Transactions of the Royal Society B: Biological Sciences. 361 (1470): 903-915. https://doi.org/10.1098/rstb.2006.1838
 * 5) Lyons, Timothy W.; Reinhard, Christopher T.; Planavsky, Noah J. (2014). "The rise of oxygen in Earth’s early ocean and atmosphere." Nature. 506 (7488): 307. https://doi.org/10.1038/nature13068
 * 6) Reinhard, Christopher T.; et al. (2016). "Earth’s oxygen cycle and the evolution of animal life." Proceedings of the National Academy of Sciences. 113 (32): 8933-8938. https://doi.org/10.1073/pnas.1521544113


 * Note that Resplandy et al. 2018 has been retracted on account of some methodological problems. See https://www.nature.com/articles/s41586-019-1585-5. &diams; J. Johnson (JJ) (talk) 22:16, 1 October 2019 (UTC)

I have concerns about the main figure with the O2 fluxes numbers assigned to various sources and sinks. I understand that they are taken from the rather old reference dating back to Walker, 1980 (book chapter). There, the annual O2 fluxes were estimated (land + ocean photosynthesis) to amount to total of 300 Gton O2/year. However, the C cycle much more recent estimates suggest that the C flux due to land + ocean photosynthesis is about 210 Gton C/year (see the C cycle wiki page and references). These numbers don't match - since one stored carbon atom (weight 12g/mol) from the atmospheric CO2 causes a "release" of one O2 molecule (weight 32g/mol). The discrepancy is more than 2x. I that suggest this matter needs attention. It would be good to link the O2 cycle fluxes mole numbers to the C cycle fluxes numbers (they don't have to match perfectly, since there is a net gain in atmospheric CO2 and the net loss in O2 is perhaps harder to measure), but some discussion and relevant references would be very useful. The current differences in wiki pages for C and O2 appear too striking. — Preceding unsigned comment added by Pauls.stra (talk • contribs) 02:16, 4 January 2022 (UTC)

Stuff at the beginning of the talk page, beforehand without heading
Seasonal O2/CO2 ratios: I am trying to find out how much, if any, the O2 ratio in the atmosphere changes with the seasons. Some sources show O2/CO2 ratios varying considerably in the summer and winter in each hemisphere. Other sources say that there is no seasonal variability,and that the O2 level is always around 20%. What's the true story here?

Why no hydrosphere? Just wondering why the overview paragraph and the image make no reference to the hydrosphere. Surely this is a significant resevoir for oxygen given that there is dissolved O2 and CO2 and there is H2O itself. - Drstuey 07:28, 22 Nov 2004 (UTC)

Answer: I decided not to differentiate between the hydrosphere and biosphere, mainly because I didn't have enough info to break down the biosphere reservoir into land surface and hydrosphere components. Also, dissolved O2 levels in the hydrosphere are a function of biologic activity. For an interesting theory on the relationship between the evolution of photosynthetic life, dissolved oxygen in the ocea, and the worlds main commercial source of iron, check out the banded iron formation. - Cbusch01 14:46, 13 Jul 2005 (MST)

Watson/Lenton

As I am researching the subject of what regulates the oxygen content of the atmosphere, I have found the works of professor Watson and dr Lenton at East Anglia University ( see here: http://www.uea.ac.uk/~ajw/pubs.htm, particular the pieces that have Redfield Revisited in their title). It is not easy stuff (as I am but a humble journalist), but what I have understood so far is that the oxygen production by photosynthesis is a netto neutral affair, in that all the oxygen produced by trees shrubs and plankton is consumed by the breakdown of these organisms. So there must be other oxygen sources and if I understand Watson/Lenton well then one of these sources is the chemical weathering of rocks by plantroots that releases oxygen in the atmosphere and the burial of marine life in geologic time that once produced oxygen but which was buried without reclaiming the produced oxygen back. Bu~t I would be very happy to see on the Wiki page how you interpret this. Thanks

Theo Richel (www.richel.org/resume) 82.176.201.176 09:52, 30 November 2006 (UTC)

Answer: The amount of "free" oxygen in the atmosphere is dominated by photosynthesis. By free oxygen I mean that in the form of O2 gas. It is true that all the oxygen produced by photosynthesis is eventually consumed by respiration and decay, but there is a lag between when it is produced and when it is consumed that allows it to remain in the atmosphere for a period of time. A good analogy for atmospheric oxygen is a stream-fed lake. Initially, the flow of water into the lake bed is greater than the flow out and the lake slowly fills up with water. Eventually the water level in the lake is high enough that the routes of escape for water can keep up with the incoming stream, thus reaching the point that the inflow and outflow are in equilibrium (the netto neutral affair you mentioned). Although the lake level is now static, it is still filled with water. In the same manner, the oxygen "lake" in the atmosphere is still full even though the level is basically static. If the photosysntesis stream were ever turned off, the free oxygen "lake" would eventually dry up. But here is the tricky part: the oxygen molecules would still remain in the atmosphere. However, instead of being in the form of free oxygen (O2), it would be converted to carbon dioxide (CO2) via respiration and decay. Without photosynthesis, the planet earth would have a nitrogen/carbon dioxide atmosphere instead of the nitrogen/oxygen atmosphere we currently enjoy. There are other sources of atmospheric free oxygen instead of photosynthesis, but these other sources produce so little oxygen that they are virtually insignificant in the big picture. By-the-way, the main source of carbon dioxide and nitrogen in the atmosphere is volcanoes. See the carbon cycle and nitrogen cycle articles for further discussion. - Cbusch01 09:23, 07 May 2008 (CST)

Oxidation of iron ores - error in chemical equation
I noticed that the stoichiometry of the equation for formation of rusts through weathering was incorrect.

4FeO + 3O2 → 2Fe2O3

I've corrected it as it shouldn't be controversial! —Preceding unsigned comment added by Parallelepipete (talk • contribs) 11:22, 14 August 2008 (UTC)

Incomplete cycle
There is something not properly noted here: the water. It's ridiculous to include photolysis in the balancing, but not, for example, the watery part of photosynthesis and metabolism. Also oceans are a far bigger reservoir than the atmosphere (I do not mean the soluble O2 here.). -- Tomdo08 (talk) 03:51, 20 December 2010 (UTC)

Decline in oxygen levels.
According to the wikipedia article about phytoplankton, phytoplankton levels have been decreasing with about 1% every year the last 111 years ( which should correspond to decline of about 67% ). I have also read that the landmass covered by rain forests have decreased from about 14% to about 6% the last century ( which should correspond to a decline of about 43% ). As phytoplankton produces about 50% of the atmospheric oxygen while rain forests produce about 28% of the atmospheric oxygen, this should correspond to a decline of about 45% in global photosynthetic activity if I am right. I also calculated from the data in this article that without any photosynthetic activity the atmospheric oxygen will be depleted in 4666.67 years ( (1.4 * 10^18) / (3.0 * 10^14) ), but the usage of oxygen must also have increased due to the combustion of fossil fuels. Perhaps some information about this should be included in the article if my calculations are right.81.167.185.42 (talk) 12:36, 30 December 2010 (UTC)

According to carbon_dioxide_emissions the amount of CO2 emitted is 36,061,710 kilo ton in 2015. That is about a 25 Giga ton of oxygen, not the stated 12 Giga ton. The source [8] mentioned the 36,240,721 for 2015. Oxygen has a 2*16/(2*16+12) mass. GerGroeneveld (talk) 21:31, 28 December 2018 (UTC)

Updating the sources data
From articles I've read and videos I've watched the belief among oceanographers is that the amount of atmospheric O2 believed to be from ocean is somewhere between 50% and 80% sources. One name in particular is Dr Charles Trick who said "Over 50%" as a conservative estimate. This wikipedia article uses data from 1980 and could probably use an update from a more contemporary source.

Cheers — Preceding unsigned comment added by 76.10.148.181 (talk) 19:09, 18 May 2013 (UTC)

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Semantics - source vs process
the page currently states that the largest source of oxygen is photosynthesis.

This is incorrect. Photosynthesis is not a source, it's a process. The source is the actual organisms that carry out the process, and of these the largest source is phytoplankton. — Preceding unsigned comment added by 122.56.26.1 (talk) 23:02, 9 October 2018 (UTC)

I may be wrong, but think that most people would consider it just as accurate to call the process the source as to call the place where the oxygen molecules used to be the source, but you could change it if you wanted to. The main effect would be to make it slightly wordier, and, in my opinion, more awkward, but it wouldn't affect understandability or accuracy much. "The main source of atmospheric free oxygen is photosynthesis, which produces sugars and free oxygen from carbon dioxide and water:" might change to "The main source of atmospheric free oxygen is photosynthetic organisms, which produce sugars and free oxygen from carbon dioxide and water:".75.117.222.22 (talk) 05:55, 27 October 2020 (UTC)

How could we make the world's ecosystem Oxygen cycle to collapse?
as per Stephen Petranek at TEDxMidwest https://www.youtube.com/watch?v=HEfpxiUIZPs - 16:20 "a marginal tree" and when that imaginary tree is cut, we will have broken the oxygen cycle. Thy --SvenAERTS (talk) 02:17, 29 October 2018 (UTC)

Improvement can be made for the resources
1. Six different sources are listed in the Reference part, which is good but not enough in my opinion, especially only one of them is a published academic paper.

2. The First source is an article in Scientific American and has a link followed, but the link has already expired. I can't see the article by clicking the link provided.

3. Sources are a bit of outdated. Two Scientific American articles are published in 2003 and 1970 respectively and the academic paper is from a book published in 1980. More recent works is available, e.g. Kasting & Canfield, 2012.

4. The fourth source is actually notes taken in a class, which cannot be considered as very reliable. Pengxiao Xu (talk) 20:32, 15 February 2019 (UTC)

Some other references
[1] Petsch, Steven (2003). "The Global Oxygen Cycle". Treatise on Geochemistry. 8:515-555 https://doi.org/10.1016/B0-08-043751-6/08159-7

[2] Reinhard, Christopher T., Planavsky, Noah J., Olson, Stephanie L., Lyons, Timothy W., and Erwin, Douglas H. (2016). "Earth’s Oxygen Cycle and the Evolution of Animal Life." Proceedings of the National Academy of Sciences 113(32): 8933-38. https://dx.doi.org/10.1073/pnas.1521544113

[3] Keeling, Ralph F. (1995). "The Atmospheric Oxygen Cycle: The Oxygen Isotopes of Atmospheric Co 2 and 0 2 and the 0 2 /N 2 Ratio." 33:1253. https://dx.doi.org/10.1029/95rg00438

[4] Kasting, James F. and Canfield, Donald E (2012). "The Global Oxygen Cycle." Fundamentals of Geobiology." ch7:92-104. https://doi.org/10.1002/9781118280874.ch7

[5] Holland, Heinrich D (2002). "Volcanic gases, black smokers, and the Great Oxidation Event." Geochimica et Cosmochimica Acta 66(21): 3811-3826. https://doi.org/10.1016/S0016-7037(02)00950-X

[6] Lasaga, Antonio C., and Hiroshi Ohmoto (2002). "The oxygen geochemical cycle: dynamics and stability." Geochimica et Cosmochimica Acta 66(3): 361-38. https://doi.org/10.1016/S0016-7037(01)00685-8

[7] Najjar, Raymond G., and Ralph Keeling F. (2000). "Mean annual cycle of the air‐sea oxygen flux: A global view." Global biogeochemical cycles 14(2): 573-584. https://doi.org/10.1029/1999GB900086

[8] Walker, James CG (1986). "Global geochemical cycles of carbon, sulfur and oxygen." Marine Geology 70(1-2): 159-174. https://doi.org/10.1016/0025-3227(86)90093-9

[9] Sleep, Norman H (2005). "Dioxygen over geological time." Metal Ions in Biological Systems, Biogeochemical Cycles of Elements. CRC Press, 43: 92-116. https://www.taylorfrancis.com/books/9780824751999/chapters/10.1201%2F9780824751999-7

[10] Betts, J. N., and Holland, H. D. (1991). "The oxygen content of ocean bottom waters, the burial efficiency of organic carbon, and the regulation of atmospheric oxygen." Global and planetary change. 5(1-2): 5-18. https://doi.org/10.1016/0921-8181(91)90123-E — Preceding unsigned comment added by Pengxiao Xu (talk • contribs) 03:29, 23 February 2019 (UTC)

"by volume" makes no sense
Up to my understanding, "by volume" related to non gases makes no sense. Like in this sentence "The lithosphere is 46.6% oxygen by volume", and in some other ones.

Wlodr (talk) 09:09, 24 August 2019 (UTC)

Oxygen cycle
A 2409:4042:2305:CD94:2EE7:7748:4F07:633F (talk) 18:33, 21 July 2022 (UTC)

Science
Oxygen cycle information 117.254.35.145 (talk) 04:16, 30 December 2023 (UTC)