It is mentioned that marine planktons contribute 50-90 percent of the oxygen in the atmosphere. This is a wide range. If that is the case what is the contribution of the vegetation on the land, naturally it is very limited.
70% of the earth's surface is covered with water & the phytoplankton dwelling in the surface waters believed to contribute around 50-85% of the oxygen in Earth’s atmosphere while others [e.g. land plants] put the number at closer to one third. It is tough to calculate the exact figure as because phytoplankton biomasses fluctuate across the seasons; blooming mostly during the spring & autumn when there’s more available light and nutrients in the water. However, land plants are also playing very important role in the process. Before the origin of land plants, photosynthesis by phytoplankton was not intensive enough to deplete CO2 from the atmosphere. Indirectly, the land plants trigger the production in the water bodies by means of say phosphate weathering from rocks. Thus in no way land vegetation contributes less to oxygen enrichment in the atmosphere, although it is really difficult to figure out the exact contribution. Both the land & water plants play inevitable roles in balancing O2-CO2 in the atmosphere and much more.
I think it is not wise to deal with them in isolation. Hope I have made it somewhat clear to you.
Regards
Dola.
Thanks Dola for the informative response. Yes, it is very intriguing. I feel this is something that people should concentrate in future. The range 50-85 per cent is a very wide one, not very scientific. Thanks for the review also.
Does somebody have a scientific reference for the 50-85% statement? I know only from the study of Behrenfeld et al. (Science 291, 2594 (2001); DOI: 10.1126/science.1055071), which gives an estimate of ~50%.
Hi Alfred, I have read this in different places, but without much scientific explanations. Please find time to look at the following link if you don't mind:
http://earthsky.org/earth/how-much-do-oceans-add-to-worlds-oxygen
A reference that states that 70% of atmospheric oxygen is produced by the oceans is this one :
Walker, J. C. G. (1980). The oxygen cycle in the natural environment and the biogeochemical cycles. Berlin: Springer-Verlag.
Thanks a lot. I'm doing contents validation for a documentary and this is a statement that we hear over and over again... oceans are responsible from half the air your breathe on the planet... Could not find a real, scientific source. Now I have one (or two!) thanks.
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