The Water Cycle
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Cycles of Matter
You have heard of the water cycle...right? There are 2 more very important cycles of matter. The Carbon Cycle and the Nitrogen Cycle How do they work? How are the like the water cycle? How are they different? What is Nitrogen Fixation? This and more answered here! FYI - did you know that all matter is recycled? |
The Carbon Cycle
All organisms contain carbon. Some organisms, including humans, get carbon from food. Other organisms,such as plants, get carbon from the atmosphere or bodies of water. Like other types of matter, carbon cycles through ecosystems. Like nitrogen, carbon can enter the environment when organisms die and decompose. This returns carbon compounds to the soil and releases carbon dioxide (CO2) into the atmosphere for use by other organisms. Carbon is also found in fossil fuels, which formed when decomposing organisms were exposed to pressure, high temperatures, and bacteria over hundreds of millions of years. The Greenhouse Effect Carbon dioxide is one of the gases in the atmosphere that absorbs thermal energy from the Sun and keeps Earth warm. This process is called the greenhouse effect. While the greenhouse effect is essential for life, a steady increase in greenhouse gases can harm ecosystems. |
The Nitrogen Cycle
Just as water is necessary for life on Earth, so is the element nitrogen. Nitrogen, like water, cycles between Earth and its atmosphere and back again. The atmosphere is 78% nitrogen. However, this nitrogen is in a form that plants and animals cannot use. The nitrogen must first be changed into a different form with the help of certain bacteria that live in soil and water. These bacteria take in nitrogen from the atmosphere and change it into nitrogen compounds that other living things can use. This process is called Nitrogen fixation Plants and some other organisms take in this changed nitrogen from the soil and water. Then, animals take in nitrogen when they eat the plants or other organisms. Certain bacteria convert nitrogen in soil and water into a form usable by plants |