Evapotranspiration aka – plant sweat

I have taken lots of pretty photos but… I will save that for my next post. The one to the left is courtesy of Environmental Monitor, an online newsletter for environmentalist – techies. I was intrigued by a new word I learned in my Wetlands class – evapotranspiration. Some people – including me have a great potential and an exuberant interest in science but can feel intimidated by all of the “scientist” talk. I have been in a wetlands class for 6 weeks and found myself “Googling” the question of whether nitrogen release in the atmosphere is bad or good. As it turns out, nitrogen is a necessary component of air:

“The air in our atmosphere is composed of molecules of different gases. The most common gases are nitrogen (78%), oxygen (about 21%), and argon (almost 1%). Other molecules are present in the atmosphere as well, but in very small quantities” http://eo.ucar.edu/basics/wx_1_b_1.html

So – nitrogen is not bad – but too much is not good. Too much can cause excessive algae growth which can kill aquatic life such as salmon.

However this is an aside. My subject is evapotranspiration. This is a long – scientific – scary word. However, in nice non-scientist terms – it simply means – plant sweat. So what does this have to do with my wetlands class? Wetland plants absorb water and then release it through their stomata – lets call them – leaf pores (just like we humans sweat through our pores). This provides two essential functions. First – the transpiration releases moisture into the atmosphere providing climate regulation and cooling. Second, as these plants use the water in the wetland, there is more space for additional water to be stored. As I understand it – this can provide benefits such as flood mitigation.

There you have it. Plant sweat is an essential part of the hydrolic cycle.  I wonder if human “evapotranspiration” also helps the environment? That may give us all more incentive to go for a run around Green Lake on a sunny day!

All you scientists out there – feel free to help me out and further explain evapotranspiration. I had a lot of help from my class and also from the websites below.





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