PDS AP Environmental Science 5th Period 2011-12

There’s a reason wind power is the face of the alternative energy movement. It’s the energy of the future: renewable, releases no carbon emissions, and, most of all, it’s adaptable. If you don’t believe me, check out this recent article from New York’s The Real Deal about the installation of wind turbines at Staten Island’s Freshkills Landfill (you may remember this from a video earlier this year). Interested? Read on…

Typical Wind Farm

This video here from the US Department of Energy (some say it’s the authority on US energy use and management, but perhaps that’s just a rumor) is the best we found in explaining the mechanics and operation of a standard wind turbine. These turbines (the tall poles with the propeller looking thingies) are very simple in their operation. Essentially, wind blows the propellers which, with the help of various gears and devices, turn an internal turbine that activates a generator, ultimately creating electricity. We’ll go into more details tomorrow, but that should give you a good background.

Wind turbines may not produce as much energy as, let’s say, a nuclear power plant, but the fact that they’re safe and versatile increases their appeal. Wind farms (a collection of turbines) can be built on hills, plains, and even oceans. As long as there’s wind, electricity will be produced. However, I don’t want to give too much away, so stay tuned for tomorrow’s presentation, it’s guaranteed to be classy.

http://therealdeal.com/blog/2012/03/20/city-issues-rfp-for-fresh-kills-solar-and-wind-facilities/

http://blogs.telegraph.co.uk/news/files/2012/02/wind-turbine-2.jpg

http://www.npr.org/templates/story/story.php?storyId=149020842

http://www.youtube.com/watch?v=tsZITSeQFR0

For the first two action-packed days following our return from the R&R of Spring Break, the focus of our in-class discussion in APES was Water Resource Issues. In nearly ninety minutes of never-dull, thoroughly engaging lecture and discussion, we covered, in brief, what our freshwater resources are, why our society experiences freshwater shortages, what solutions we put in place to combat these shortages, the environmental impact of how we combat these shortages, and how we can conserve our water resources.

First, we went over some basic facts about our planet’s freshwater supply. Though there’s a tremendous amount of water on Earth, only about 3% of Earth’s water is freshwater. And of this freshwater, roughly 3/4 of it is frozen (see below), and roughly 1/4 of it is below ground. In fact, only about 1% of Earth’s freshwater exists as surface freshwater.

A glacier, one example of frozen freshwater (Source: http://www.iceagenow.com/HubbardGlacier.jpg)

This background information led us to our next two topics: why our society experiences freshwater shortages and what solutions we put in place to combat these solutions. To know why our society experiences freshwater shortages, one needs only to remember the four D’s: dry climate, drought, desiccation (dry soil), and demand. Each of these conditions has the potential to be responsible for a society’s having an either insufficient or unsustainable supply of water. As for the solutions to these problems, they can also be remembered by recalling four five D’s. The five solution D’s are dams (see below), diversion, drilling, desalination, and demand reduction. With these “solutions,” we, as a society, are able to combat the freshwater shortages brought on by the other D’s.

The colossal Hoover Dam (Source: http://www.visitingdc.com/images/hoover-dam-directions.jpg)

These “solutions,” however, aren’t entirely perfect. Though each of them combats freshwater shortages, each them–with the exception of demand reduction–comes with adverse environmental impacts. Building dams or water transfer apparati (diversion) involves habitat destruction, which, in turn, leads to a loss of biodiversity. As for drilling for groundwater, it has the potential to cause a host of environmental issues, including water table lowering, depletion from overdrafting, subsidence (which can lead to sinkholes), saltwater intrusion, and chemical contamination (a graph detailing such contamination of groundwater can be seen below).

Groundwater Contamination (Source: http://groundwater.org/gi/images/contamination_diagram.jpg)

Finally, we discussed strategies for reducing water demand/conserving freshwater resources. Since so much of our freshwater–70 % of it on a global scale–is used for agriculture, one strategy that figured prominently in our discussion was efficient irrigation. With new technologies like drip irrigation and LEPA sprinklers (see below) farmers can now irrigate their fields with greater than 90% efficiency. We also discussed water-saving technologies like better-designed shower heads, toilets, and other household appliances. Furthermore, we examined the benefits of improved water management techniques like tiered water prices and the use of gray water by municipalities.

A LEPA Sprinkler (Source: http://www.senninger.com/wordpress/wp-content/uploads/2010/04/LEPA-QuadSpray-Circle-sm.jpg)

In short, Monday and Tuesday were two very scholarly, very productive days in APES. For all of those of you who were in class, I hope you had as much fun as I did. Hopefully, you’ll find this summary of the day’s activities to be helpful. Peace.

Hello All,

Here’s the story of a man who fought for something for which he deeply cared. It inspired me, and perhaps it will inspire you, too.

http://www.colbertnation.com/the-colbert-report-videos/171137/june-10-2008/alan-rabinowitz

I’m a little confused about extinction and the theory of island biogeography. Why is it that a large island near the mainland would have a high immigration rate and a low extinction rate. Wouldn’t the high immigration rate cause the population to exceed the carrying capacity and experience a crash or extinction? I would appreciate any help anyone has to offer.

During our final APES class of No-Shave November–when beards and peach fuzz raged with a never-before-imagined fury–we discussed The Theory of Demographic Transition.

In essence, the theory of demographic transition is a model that explains how a country’s birth rate, death rate, and population change as it transitions all the way from a preindustrial to a postindustrial society.

To ease our understanding, the theory of demographic transition is broken down into four stages.

Stage 1: Preindustrial (undeveloped)= slow growth. In this stage, birth rates are high, but due to the fact the country is undeveloped–and, therefore, has poor sanitation, little health care, and likely poor food distribution–death rates are equally high. For that reason, population stays relatively low and experiences no growth.

Stage 2: Transitional (most developing countries)=rapid growth. In this stage, as a country begins to develop, improves its sanitation, gains access to better health care, and improves its ability to produce and distribute food, its death rate declines rapidly. Its birth rate, on the contrary, stays high, and as a result, the country’s population grows tremendously.

Stage 3: Industrial (most developed countries here)=stable. In this stage, death rates remain low, and additionally, as women gain more access to birth control and receive greater educational opportunities, birth rates begin to fall, causing the population to begin to stabilize.

Stage 4: Postindustrial (very few developed countries here)=declining. When a country reaches stage four of the theory, it residents have achieved a relatively high level of affluence, and the country has experienced a tremendous deal of economic development, both of which lead to low birth and death rates and, not surprisingly, a possible decline in population.

Here is a graphic representation of the theory.

Source: http://bit.ly/usaeoA

One interesting conclusion to draw from this theory is that, if we want to bring better living conditions to an undeveloped country, the best thing we can do is jumpstart it economically. A Swedish doctor by the name of Hans Rosling, however, has somewhat different ideas. His contends that we need to bring health before wealth to undeveloped nations and that all data must be contextualized.

A TED talk in which Rosling shares his ideas and statistics about the matter is here.

Hans Rosling shows you the best stats you\’ve ever seen

On Tuesday of this fine late-September schoolweek , we spent some time discussing Ecological Efficiency/Energy Flow in ecosystems.

An ecosystem, of  course, is a particular location on Earth, distinguished by its mix of interacting biotic and abiotic components. Ecological efficiency/energy flow (ecological efficiency is the more “scientific” of the terms) refers to the proportion of consumed energy that can be passed from one trophic level to another.

Typically, ecological efficiency is visualized in the form of pyramid.

A pyramid demonstrating ecological efficiency (source: http://www.globalchange.umich.edu/gctext/Inquiries/Inquiries_by_Unit/Unit_4_files/image006.jpg)

At the bottom of the pyramid sit the primary producers, who, by way of photosynthesis, produce a large amount of energy. On the next level sit the primary consumers: those who eat the primary producers. As the picture depicts, although the primary producers able to store a large amount of energy, only 10% of that energy is transferred to the next trophic level–all the rest is lost in the form of heat. This trend continues with subsequent trophic, all the way to the top of the pyramid. So by the time the tertiary consumers are eating the the secondary consumers, they are only receiving a small, small amount of energy.

The last thing we discussed in class was Net Primary Production (NPP). Net Primary Production accounts for the amount of energy available to be used by consumers after the producers have performed respiration and can be expressed by the equation Net Primary Production = Gross Primary Production – Respiration (NPP = GPP – R). Ultimately, NPP is essential for an ecosystem, as it is the energy leftovers on which all of the consumers depend.

The way I see it, the most pressing environmental issue our world faces today is climate change. Little doubt remains, I think, that human activity has led to a detrimental warming of earth’s climate, and so it’s imperative that we, as a human race, work together to combat further harm to our planet through global warming.