PDS AP Environmental Science 8th Period 2010-11

Hey y’all-

I don’t know why I didn’t think about this before but a while ago I found out about this seach engine, which is powered by Google, called Blackle. It saves energy by just having the background being black instead of white. It’s pretty cool, so check it out. I posted a link with specifics on how it saves energy.

http://www.blackle.com/about/

So I have 2 questions:

1. I’m confused about question number 4 in section V on the ch. 16 study guide, which is “What factors mask population declines in ocean fisheries and make global catch seem relatively stable?”The wording on this was unclear in the textbook. For one, it said that fishing fleets travel longer distances to reach less-fished portions of the ocean and they fish in deeper waters. But how exactly does fishing deeper and farther away mask population declines?

2. Also, on number 3 in section VI of the ch. 16 study guide, which asks about the issue of China’s fisheries data. I know the fisheries reported that they caught more fish than they actually did to fill a quota, but what is the environmental impact of this inaccurate reporting?

Thanks!

Hey y’all-

So I’m kindof confused between chemical and physical weathering. I understand biological, but chemical and physical seem too similar that I can’t tell the difference between them. For example, I know that rain is an example of physical weathering, but when water reacts with rock to break it down, that is considered chemical weathering. Can anyone help me differentiate the two?

Thanks

Thursday, February 17, 2011

Today in class, we discussed Soil Degradation and Conservation, Chapter 9 (part IV of study guide), but mostly focused on erosion and ways to prevent erosion.

First, we discussed the causes of degraded soil, which are:

• overgrazing
• deforestation
• cropland agriculture
• industrialization

We also talked about the different types of degraded soil, which are:

• erosion (the dislodging and movement of soil from one area to another. is part of both formation and destruction of soil)
• desertification (due to drought and human activities, occurs most in desert biomes)
• salinization (caused by evaporation of water from soil and leaves salts in soil, result of irrigation)
• waterlogging (attempt to leach salts deeper but raises water table, results in “root rot” and lack of oxygen to roots, too much water in soil prevents nutrients from getting to plant roots)
• decreased fertility

From there, we elaborated on erosion. Erosion is a problem in the A horizon and eroded soil takes centuries to be  replenished. The number 1 erosive force is water, although wind erosion is a problem, too. Erosion occurs faster than soil formation, so this means that soil is a potentially-renewable resource (since it can reform, but very slowly). Soil fertility decreases as organic matter is eroded away, since there the nutrients are being drained from the soil. Erosion is a major cause of water pollution, being that main water pollutant is sediment. Erosion occurs from both natural (ex: rain) and human activities(ex: overgrazing).

Some legislation was created to address problems with soil conservation, including the Soil Conservation Act, which led to the Natural Resource Conservation Service (1935) and the Food Security Act (1985). During the Dust Bowl, the Soil Conservation Act created soil conservation programs and promoted no-till or low-till farming. The Food Security Act provided subsidies for farmers who did not farm on degraded soil and instead planted trees or grasses on this land. These measures were made in order to revitalize the unarable soil.

To combat/prevent erosion, farmers use the following techniques on their cropland:

• Crop Rotation–alternating type of crop grown in a field each season so that the nutrients from corn, for example, aren’t completely drained out of the soil in three growing seasons. This method returns nutrients to the soil, breaks disease cycles, and minimizes erosion that comes from fields laying fallow.
• Contour Farming–plowing furrows sideways across a hillside perpendicular to the slope to prevent rill and gully erosion.

• Terracing–level platforms on mountains with raised edges to decrease the amount of soil lost to erosion (the precipitation will catch less soil as it runs down the mountain, perpendicular to the terraced levels).

• Intercropping–alternating bands of crops slow erosion by providing more ground  cover than a single crop and reduces vulnerability to insects and disease.

• Shelterbelts/Windbreaks–rows of trees or tall, perennial plants to slow wind erosion. Sometimes combined with intercropping when the tall perennials are sources of fruit, wood, or other crops.

• Reduced Tillage–use cover crops and crop residue on soil to restore nutrients to soil and only cut shallow groove into soil to plant seeds instead of inverting the soil. This increases organic matter and while decreasing erosion.

  

  http://www.marketfarmequipment.com/Chisel_Plow_Leveler_-_IHC_2x.gif

  Low-Tillage Machine

We also watched this video in class, which is a basic explanation of erosion, how soil is affected by erosion, and what we/farmers can do to prevent it.

http://www.youtube.com/watch?v=_UeVvUzgJAY

So after watching Bill McDonagh’s video and seeing his book today, I googled the book and I found what it’s made out of (because I know a few people were interested in that). Here’s the website (the information on the book design is in the last paragraph)

http://www.mcdonough.com/cradle_to_cradle.htm

So I was doing my research for my global leadership paper and I came across this which I found quite amusing. It was from Answers.com. Enjoy.

Question: “When did littering become a wordwide problem” Answer: “the littering had been a big problem around the world all the time. Littering is a really bad because it can hurt us and the earth. so if your the one who is littering, then STOP IT!!!!”

Hey y’all-

So I saw in my notes that the higher the temperature, the higher the biodiversity. So that would mean that tropical biomes would have the most biodiversity which doesn’t make sense to me because only very specific types of organisms can live in these harsh climates. It makes sense to me to say that temperate climates have the most biodiversity since they have a very adaptable, non-extreme climate. Can someone clear this up for me? Thanks! Nat

For the global wind directions, I am confused as to why each “pair” of winds goes the direction they do. I understand that warm air rises and cool air falls and I understand that the rotation of the Earth causes winds to go East and West instead of just North and South but for example, why do the trade winds above the equator go the opposite direction of those below the equator? In other words, why do the pairs go in opposite directions? Also, why do the polar convection cells go the same direction as the hadley cells (tropic level) if the air temperature is significantly different?

Thanks!

can someone help me figure out what neoclassical economics means? it keeps showing up in the chapter review quizzes and i can’t exactly pinpoint what it means. thanks!

can anyone help me distinguish between an environmnent and an ecosystem? the textbook definitions are very similar but I don’t understand the difference between the two