Biogeochemical Cycles s2

Biogeochemical cycles I. CARBON CYCLE

(1) Go to http://www.epa.gov/climatechange/kids/basics/today/carbon-dioxide.html Click and complete scene 1.

(2) Name 2 places on the earth we find carbon: 1. ______2. ______

(3) Go to http://www.windows.ucar.edu/tour/link=/earth/Water/co2_cycle.html, read about the carbon cycle and fill in the blanks below:

Plants pull carbon (in the form of carbon dioxide) from the atmosphere to make food, through a process called ______.

Through food chains animals get ______from the plants and other animals they eat.

When plants and animals die and ______, carbon goes back into the ground.

Some carbon is buried deep in the ground and forms ______.

When humans burn fossil fuels, ______is released back into the atmosphere.

When humans and animals exhale, they release carbon back into the air by a process called ______.

(4) Go to http://www.windows2universe.org/earth/Water/co2_cycle.html

How are oceans involved in the carbon cycle?

How is the temperature of the Earth partly controlled by carbon?

What role do rocks have within the carbon cycle?

How are humans altering the carbon cycle?

(5) Use this site to play a carbon game: http://www.windows2universe.org/earth/climate/carbon_cycle.html Click to begin your journey. Take notes on (1) where you begin the carbon cycle, (2) the stops that you make, and (3) what you learn along the way.

Facts to find: How much of the atmosphere is made of carbon dioxide? By how much has CO2 increased in the atmosphere during the past 150 years? The deep ocean accounts for more than ______% of the Earth’s carbon. How much carbon does the surface ocean absorb from the atmosphere each year? True or false. When plants die and decay, they bring carbon into soil.

True or False. Plants both absorb CO2 from the atmosphere and release it into the atmosphere. True or False. Phytoplankton are tiny plants and algae that float in the ocean and take up carbon dioxide as they grow. When carbon enters the deep ocean, how long does it stay there?

II. NITROGEN CYCLE Go to the website: http://www.windows.ucar.edu/tour/link=/earth/Life/nitrogen_cycle.html&edu=mid and answer the questions below:

1. For what three things do plants and animals need nitrogen?

2. What are 2 ways nitrogen becomes useable to plants, humans and animals?

3. How do herbivores obtain the nitrogen they need?

4. How is nitrogen returned to the atmosphere?

5. What are two ways humans impact the nitrogen cycle:

6. What happens when there is an excess of nitrogen?

Like carbon, nitrogen must be recycled continuously. Go to the following websites to learn how this happens: http://www.cst.cmich.edu/centers/mwrc/nitrogen.htm

1. Where is most nitrogen in the biosphere located?

2. This nitrogen is not in a useable form. Plants and animals cannot simply absorb nitrogen from the atmosphere. Therefore, it must be ______, which means ______. 3. There are two ways that nitrogen can be removed from the atmosphere: a) b) 4. What happens to nitrogen inside of a plant?

5. How does the nitrogen get to carnivores?

6. What happens to the nitrogen when organisms die?

7. What is the name of the process that returns nitrogen to the atmosphere?

8. Go to the following site and place a number next to the steps involved in the nitrogen cycle: http://ridge.icu.ac.jp/gen-ed/ecosystem- jpgs/nitrogen-cycle.jpg

o nitrogen-fixation – (nitrogen in atmosphere converted to ammonia by lightning or nitrogen-fixing bacteria) _____ o nitrification (ammonia converted to nitrates by nitrifying bacteria)______o assimilation (plants absorb nitrates, incorporate into proteins. Nitrogen in now in the food chain) _____ o ammonification (dead plants/animals converted to ammonia by ammonifying bacteria) _____ o denitrification (some nitrates are returned to atmosphere by denitrifying bacteria) ______

9. What type of organism do you notice is essential in nearly every stop of the nitrogen cycle?

III. WATER CYCLE 1. http://education.jlab.org/reading/water_cycle.html 1. The ______evaporates ______from lakes and oceans. As the air rises, it cools. The water vapor condenses into tiny droplets of ______. The droplets crowd together and form a ______. Wind blows the ______towards the land. The tiny droplets join together and fall as precipitation to the ______. The water soaks into the ground and collects in ______. The ______that never ends has started again! 2. Identify each number in the picture below IV. PHOSPHOROUS CYCLE Go to: http://filebox.vt.edu/users/chagedor/biol_4684/Cycles/Pcycle.html and answer these questions based on the “soil based view” of the phosphorus cycle. 1. How does phosphorus initially enter the cycle? 2. What do plants do with it? 3. How do herbivores get it? 4. How do carnivores get it? 5. How do herbivores and carnivores return phosphorus to the cycle? 6. Why do living things need phosphorus?