PDS APES 5th Period 2009-10

http://www.bynon.cc/blog/atmosphere.jpg

In class, we dicussed what made up “good air” and how it was defined.

First things first, we talked about how in Environmental Science, we mostly focus on the troposohere and the stratosphere. There are several differences between the two, but they both hold very important roles in providing “good air”

Trophosphere vs. Statosphere

Trophosphere = the air we breathe, where weather occurs, and is made up of 78% Nitrogen, 21% Oxygen and 1% “other” (more about that later), global warming, and the danger of ozone at this level.

Stratosphere= global winds and higher levels of O3, ozone thinning an issue, ozone= global sunscreen-necesary to block UV rays.

Overall, air in the trophosphere is comprised of 78% Nitrogen, 21% Oxygen and the 1% “other” made mostly of Co2, methane, water vapor and argon. Too much of one of these gases causes what we call “bad air”.

So in class, we’ve discussed how landfills are now the norm over incinerators due to the fact they are more convenient, less expensive and don’t release as many toxins into the air. So I guess my question is, why are incinerators still being built and used if the landfill is overall better for the environment? Is it a matter of convienience or cost? Thanks to anyone that can help!

Today was an exciting day in APES. We continued out discussion on by far the most exciting topic in the book, soil degradation and conservation! Now, before accusing me of being uneccesarily sarcastic, let’s look at why soil degradation and conservation is such an important topic.

First, we did a quick review of soil horizons/layers and nutrient leaching. Remember- “O” layer = leaf litter, “A” layer = topsoil. This will come into play shortly, I promise. Stay with me.

There are five ways to degrade soils, both naturally and unnatually: erosion, desertification, salinization, waterlogging, and decreased fertility. Humans have a part in all five of these issues, but erosion is by far the most pressing issue regarding soil degradation for two main reasons:

1. The topsoil level (A-layer, remember?) takes centuries to form an acceptable layer to support plant life.

2. Over 80% of our food supply is dependent on topsoil, and that’s not even counting the meat products we consume that depend on plants.

What causes erosion? Two main natural factors: Wind and Water.

Water is the largest eroder of the topsoil and with it come numerous other environmental effects, such as runoff and sediment pollution in bodies of water.

Then the humans come into play. Through agriculture, farmers have tilled soil to it’s death. The act of tilling and ploweing has churned up the topsoil layer, allowing the particle to become loose and more likely to be degraded by the two natural factors, wind and water.

http://www.dartmoor-npa.gov.uk/print/lab-erosion.gif

What can we do to decrease soil erosion?

Farmers: practice low or no till farming methods and lessen soil exposure.

Educationally: the government soil conservation program (NRCS).

Governments: provide susbsidies to keep farmers from planting on erodible land.

The following is a short and somewhat unintentionally hilarious video clip about how farmers can decrease soil erosion.

Soil Conservation

Ways to control erosion:
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Terracing

http://4.bp.blogspot.com/_zzB_LTb_7gQ/RlFz75KteDI/AAAAAAAAAB8/Kejcs5Uu_tc/s320/terracing.gif
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Contour planting and strip cropping

http://www.thisland.illinois.edu/60ways/images/17b.gif
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Alley cropping

http://www.ncga.com/files/Alley.jpg
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Windbreaks

http://pafarmgirl.files.wordpress.com/2009/09/windbreaks.jpg
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So this afternoon I was thumbing through my parents’ “Time” Magazine and came across a very interesting article about natural selection and how our ideas about evolution may be challenged. Basically, the article talks about how the outside environment affects our genes more drastically than we thought and how those changes may actually be being passed through to our children. This would completely debunk several of Darwin’s points about evolution. Even though it really has nothing to do with the section we are reading, I think it would be very interesting considering all of the discussions we’ve had about the differences between Lamarck and Darwin’s different theories.

http://www.time.com/time/health/article/0,8599,1951968,00.html

Ok, here is one of those, “its really late and my brain is dying so this might sound stupid” questions. I was looking over the trophic levels and the way they are labelled. I understand why the producers are trophic level 1, primary consumers are level 2, etc. However, totally forgot the point of the other labelling system, which begins with primary consumers and looks like a 1 followed by a degree mark. If anyone could explain the point of this, that would be fabulous. And thanks to everyone for the help about the soil!

So basically, I was looking through my Chapter 3 study guide and discovered that I completely skipped the question on soil horizons (sorry Mr. Willard!). Anyways, I went to page 49 and looked at the diagram like the packet said, but I found the whole explanation somewhat confusing. Why are the “O” and “A” layers named two different things when the diagram basically says they hold the same purpose? If anyone could clarify, that would be awesome!

In class we discussed human population growth rates in regards to 3 different equations. Each equation took into account certain aspects of population growth, including constant birth rate (CBR), constant death rate (CDR), annual growth rate (AGR), and doubling time. All three of these equations assist us in predicting future populations of any given area bases on the current year’s population.

1. Rule of 70

It is important to keep in mind that the AGR must be expressed in terms of a percent in order for the equation to work. That being said, do not change the percent to a decimal form, for example 7% to 0.07.

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2. Annual Growth Rate

The number you get from the AGR formula will already be in a precent form. Do not try and “change” it into a percent by shifting the decimal places.

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3. Annual Population Increase/Decrease

The Annual Population Increase/Decrease formula is tricky. There are a lot of places for errors to be made, so it was suggested in class to utilize scientific notation, then change the answer back to standard form. It would still work to do the entire equation in long form, but there are more room for errors.

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Hey guys, I don’t know if this was brought up in class while I was sick, but it would be great of I could get some clarification on this. The book discusses point-source pollution and nonpoint-source pollution, point source pollution being single sources of pollution and nonpoint sources being dispersed and hard to identify. Burning fossil fuels is considered a point source, and this is where I become confused. The book claims that nonpoint sources are difficult to cleanup as they become dispersed. Wouldn’t burning fossil fuels be in this category as cleanup of these forms of pollution are nearly impossible? I understand that they come from a single source (hence the point-source), but couldn’t it be kind of both? Sorry if this is hard to understand, and thanks for the help!