I have been assigned to write an essay on "The Biochemical Fates of CO2." I would really appreciate some pointers in the right direction. Can anyone help???
Submitted by: Zakki in London
Answer:
Yes, perhaps we can help. Our first suggestion is for you to realize that everything, including CO2, is always in a state of flux, on one time scale or another; so, there is really no ultimate "fate" of CO2. Nevertheless, there are a number of different reservoirs where CO2, or its derivatives, can remain for very long times. Which brings up another point ...
At first we wondered if you meant Fate, in the singular, in the title of your assigned essay; but after thinking about it, we decided that Fates, in the plural, is really the more correct, because of the different routes that can be taken by CO2 once it is released into the atmosphere.
Suppose, for example, that you burn some coal, gas or oil. The CO2 produced by the combustion process can go a number of different directions. Some may make its way high into the atmosphere, travel around the world a couple thousand times, and then be absorbed into the surface of the ocean. If it dissolves into the North Atlantic, it might sink to great depths and become part of the transoceanic "conveyor belt" system that sets certain limits on earth's surface climate in many parts of the world. On the other hand, if it is assimilated by a microscopic plant it might sink with its host when it dies, or be eaten by a slightly larger, but still tiny, animal. Sooner or later, however, it will probably make its way to the depths of the sea, where over the eons it will be subducted under one of the continents, only to return ages later in the form of gaseous CO2 emitted by an explosive volcanic eruption.
This time around, the CO2 molecule - already once or more times destroyed and reconstituted (with probably different atomic partners) - may be assimilated by a blade of grass that is eaten by a cow that ultimately makes its way into a hamburger that you "assimilate." Now the carbon and oxygen atoms that made up the molecule are somewhere inside of you doing their part to provide you with some essential or non-essential service. Maybe they're even part of the neural system of your brain that enables you to read and comprehend this message. On the other hand, maybe you will respire them in a deep breath, as you wonder why you even asked us for help.
Ah, such is life and death, and everything in between. It's one eternal round; and CO2 and its derivatives are everywhere. And who can say what's most important? Although a daunting task to choose, we're especially fond of the role played by CO2 in sustaining life; and as you peruse our website, you will discover numerous examples of how plants grow ever more abundantly as the air's CO2 content rises.
So, do your part. Eat a plant. Grill a steak. Burn some coal. And write a good essay! But above all, keep exhaling. Your unwanted CO2 is a starving vegetable's most coveted resource.