2.04 Honors: Nature's Way: Recycling

The Honors student will:

Explain the importance of nitrogen in living things

As you are learning, when you're up here in the mountains, the weather can be a little tricky and storms come in quickly. (Roll your mouse over the lightning to hear what we're experiencing.) Sure is a good thing we're able to use this hiker's cabin for shelter!

While we're taking a break waiting for the storm to pass, let's talk about one more cycle in nature - the nitrogen cycle. We just saw how the Earth recycled water and carbon; well, it cycles nitrogen too. All living things need nitrogen as well as water and carbon. Nitrogen is a major component of proteins, the stuff that our bodies are made of. There is actually a connection between lightning and the nitrogen cycle that you'll see in a minute.

The Nitrogen Cycle

Note: You'll want to add information from this section to your Travel Log notes page.

Nitrogen is a key element in things like proteins and in the genetic make up of living things. You know if it wasn't for protein, your muscles would not become big and strong. We also need nitrogen in DNA. The air you breathe is about 78 percent nitrogen gas; however, most living things can not use this form of nitrogen. You and I get our nitrogen from the foods we eat. Meat and other protein sources are high in nitrogen content.

A diagram of the nitrogen cycle. N2 in the atmosphere can be incorporated into plants through nitrogen fixation. Plants turn N2 into NH4+ then to NO2- and then finally into NO3-. When organisims die the process of denitrification turns the NO3- back into N2 gas.

Notice from the picture that there are two ways that the nitrogen gas in the air is converted into a useable form for living things. Those two ways are:

lightning strikes
nitrogen fixation - bacteria in soil can convert nitrogen into a form that living things can process. This process is how most nitrogen gas is changed into the nitrogen we use.

Nitrogen can be returned to the ecosystem through animal wastes and through the decay of dead organisms. Nitrogen is a key ingredient in the commercial fertilizer you put on plants. Without nitrogen-fortified fertilizer, our farmers couldn't produce nearly as much food as they currently do!

Text-only version

The Nitrogen Cycle (01:37)

Problems Caused by Man

As you can see nature has a way of cycling nitrogen and keeping it in balance. However, add man and our modern ways to the mix and we have some problems. To investigate the problems associated with nitrogen, first go to the Environmental Protection Agency web site and read about the following human health and environmental problems. (When you get to the site look for the "Why should we be concerned" section)

acid rain (biodiversity)
eutrophication
nitrification of water

U.S. Environmental Protection Agency: Mid-Atlantic Integrated Assessment: Nitrogen

Not so good huh? Nope; but it's not hopeless.

Now that you understand how man is mucking it up a bit in relation to nitrogen in our environment, let's see what some folks are doing to try to fix some of these problems.

Open and print Page 1 of the report found by clicking the Long Island Sound Study link below.
Use the report page to complete the analysis items in the Article Reading and Analysis page (linked below).
1. Open, print, and save the Article Reading and Analysis document as an .rtf file. You will submit it as the assessment for this lesson.

Long Island Sound Study | Article Reading and Analysis

Important: Make sure that you have all the items answered and that you have placed a copy in your Travel Log and have a saved .rtf file to submit as the assessment for this lesson.

2.04 Honors Nature's Way: Recycling
15 points

Note: You should have completed the regular portion of the activity and should have already submitted the assessment for that part of the activity. If you have not done so, please do that now.

To complete the Honors activity, go to the assessment area and submit your completed Article Reading and Analysis page as an attachment to 2.04 Honors Nature's Way: Recycling.

Lightning image public domain, nitrogen cycle © NASA 2006 http://soil.gsfc.nasa.gov/NFTG/nitrocyc.htm, globe © clipart.com 2006