Oxygen is the component that sustains life on earth. Too much or too little of it could change the entire life scenario on the planet. How does nature then keep the oxygen content in check?
IT IS the phosphorus element that holds
the key to the oxygen feedback mechanism, according to Philippe Van
Cappellen of the Georgia Institute of
Technology in Atlanta and Eltery Ingall
of the University of Texas at Austin, us.
Atmospheric oxygen is mostly produced by the photosynthetic algae floating on the surface of the sea. Excess oxygen is consumed by the ongoing
process of weathering whereby rocks
disintegrate into soil. This also releases
phosphorus which is eventually carried
off into the sea, where it is a vital nutrient for the algae. "There is only one
source of phosphorus for the ocean and
that is weathering," says Cappellen
(New Scientist, Vol 149, No 2015).
The duo have now developed a
computer model simulating the earth's
mogeochernical cycles. 'The model
assumes that excess phosphorus in
marine algae is recycled through the
farces of animals further up in the Cood
chain. The facces, with the phosphorus
content, is incorporated into the sedi
ment by aerobic bacteria. Phosphorus
'burial' takes place when there is SLIr
plus oxy en in the ocean; when the conditions reverse, phosphorus is 'leaked'
out into the sea due to death and decay
taking place in the oxygen deficient
environment. According to the model,
the alternative processes of 'burial' and
'leakage' holds the key to the earth's
oxygen balance.
When excess weathering takes place,
large amounts of oxygen is removed
from the atmosphere and consequently
from the sea. In spite of this, there is no
apparent change in the oxygen content.
As the model revealed, this was because
phosphorus is released from the bottom
sediments as a result of oxygen depletion. Excess phosphorus in turn resulted
in an explosion of the algal population,
releasing oxygen back into the
atmosphere. And in the presence of
dangerously high levels of oxygen, the
bacteria work overtime removing the
phosphorus from the water and
depositing it in the seabed, thus starving
the surface algae of nutrients.
We are a voice to you; you have been a support to us. Together we build journalism that is independent, credible and fearless. You can further help us by making a donation. This will mean a lot for our ability to bring you news, perspectives and analysis from the ground so that we can make change together.
.png)
Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.