PDS AP Environmental Science 5th Period 2010-11

*Note: SargeK moved to the other class, but since we have no one to do geothermal, here is a guess post by him.

Earth's Natural Heat

Geothermal Energy is essentially using the earth’s natural heat for power. One way the process works is the heat from the earth warms water, which evaporates to steam. The steam is then used to turn turbines that then generate electricity. Geothermal energy is a good clean way to power and heat the world’s towns and cities without needing too much coal. There are many towns around the world reliant on geothermal energy, such as this one in China:

The concept of using the earth to heat our homes is pretty cool, if you are more interested in figuring out how this direct geothermal energy works, check out this link from howstuffworks.com: http://www.howstuffworks.com/environmental/energy/geothermal-energy.htm.

Keeping the Japan Nuclear Crisis in mind, you can’t help but wonder if other sources of energy can/would help Japan recover. To ease you curiosity, check out this news report about the potential for geothermal energy in Japan: http://www.sify.com/finance/analysis-hot-air-can-geothermal-help-japan-in-crisis-news-economy-ldyoksdhfid.html. In the grand scheme of things, geothermal energy provides a generally renewable source of energy. Although it cannot be used to fuel vehicles like biomass has potential to do, it is very efficient for heating and cooling buildings. Geothermal energy is a solid investment in the world’s future.

Can someone help me clarify the difference between sympatric and allopatric speciation? They seem pretty similar and I’m not quite sure of the exact difference.

I know that the good majority of nitrogen is fixed by bacteria, but for the nitrogen that gets fixed by lightning, is it the same reaction as with bacteria or are the formulas different?

Today we started off class by doing a whiteboarding activity. In this activity we got into groups of 3 and were instructed to determine the main reservoirs of nitrogen, its unique characteristics, and the human impacts on the nitrogen cycle. After each group was finished, we brought the whiteboards into the classroom and as a class went over each category. We determined that the three main reservoirs (in order of most nitrogen to least) are the Atmosphere, the Oceans (inorganic nitrogen), and thirdly regular soil.  The fact the the largest reservoir is the atmosphere is not surprising considering that nitrogen makes up 78% of it. In the oceans, nitrogen is found in an inorganic form, meaning that it is not bonded to carbon. Coming in a distant third, soil contains the nitrogen that is fixed by bacteria through the process known as nitrification. We determined that the unique characteristics of nitrogen are that in the form of N2 it is very stable due to a triple bond, it is also unique that nitrogen cannot go from the atmosphere to the biosphere without some sort of fixation (usually bacteria). Nitrogen can be taken up by plants through the roots, thus it is water soluble. The final unique characteristic we decided was the quickness in the nitrogen cycle due to a decent amount of flux. The human impacts on the nitrogen cycle are mainly found in the production of fertilizers using the haber-bosch process of artificial fixation, and in burning fossil fuels which leads to acid rain.  A very clear and detailed image of the nitrogen cycle can be found in the unit 4 study guide, however, this is what it looks like:

Image source: http://www.fossweb.com/resources/pictures/16327852.gif
A nitrogen cycle animation can be found at: http://www.classzone.com/books/ml_science_share/vis_sim/em05_pg20_nitrogen/em05_pg20_nitrogen.html
and a nice video at: http://www.youtube.com/watch?v=AqE-0VPHWbM
In class, we also stressed the point that the nitrogen cycle is driven by bacteria. After we went over the cycle, we reviewed some equations involving nitrogen. We reviewed all of the nitrogen cycle equations. These are nitrogen fixation (N2 -> NH3 or NH4+), Nitrification (NH3 or NH4+ -> NO2 -, NO2- + H2O -> NO3- + 2H) and Denitrification (NH3 or NO3- or NO2- -> N2), we did not need to know the Haber-Bosch process. We also quickly touched on the nitric oxide air polution formulas (N2 + O2 -> 2NO, 2NO + O2 -> 2NO2, and NO2 + H2O -> HNO3). All of these equations can be found in the yellow “I Must Have That Formula” handout, I believe it can be found in “the box.”

I think that the biggest environmental problem in the modern world is pollution. It is a problem that we don’t see too much of in the USA, however in many foreign/developing countries pollution is rampant. After living in China for 4 years I had to deal with massive pollution on a daily basis. Smog in the air, garbage in the streets, and chemicals in the rivers are serious problems, especially when many local people rely on the river for in-home water which can be very dangerous.