Plants in High CO2 Concentration
Can plants survive in pure carbon dioxide?
Seeds should survive, but germinating and growing plants so require oxygen
(usually at night) for respiration and growth.
No. While plants take up carbon dioxide and give off oxygen in
photosynthesis, they must also use oxygen during respiration, in order to
live and grow.
This is a complicated question: The easy part is -- a plant would not do
well in pure CO2 because the CO2 would dissolve in water making carbonic
acid. This would make the soil and air too acidic, i.e. the pH would
decrease a couple of powers of 10 and the plant would likely not survive.
Having said that, SOME plants do grow faster when the level of CO2 is
increased from its ambient concentration of about 350 parts per million (by
volume) to say 600 parts per million. This acceleration in growth does not
apply to all plants.
As you probably know, the atmospheric concentration of CO2 is an issue
in global warming. The level of CO2 in the atmosphere is increasing. Some
scientists believe that the "average global temperature" is also increasing,
and they attribute the temperature increase directly to the increasing level
of CO2. This conclusion is not accepted by other scientists. They argue that
an "average global temperature" is meaningless, because the temperature
varies so much with time of day, location, season, altitude, and on and on.
In addition, they argue that CO2 is part of a non-linear feedback web
involving the land, oceans, atmosphere, plant cover, etc. The puzzle is that
the increase in the level of atmospheric CO2 is only a fraction of the
amount of CO2 generated by humans, so where did it go?
My opinion, strictly mine, is that the level of atmospheric CO2 is part
of a complex interaction of sources and sinks and we do not understand the
robustness of the feedback connections. So it is an oversimplification, and
maybe an important one, to say the level of CO2 in the atmosphere is the
direct result of burning hydrocarbons. The real world is much more
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Update: June 2012