Biogeochemical Cycles Unit Objective Students will be able to… Draw and label the water, carbon, and nitrogen cycles and explain what happens in each part of the cycle.

Matter and Living Things An Introduction to Environmental Chemistry Brainstorm: What do living things require?

atmosphere temperature energy TWANE water nutrients

A Terrarium A terrarium represents the components of an ecosystem and illustrates the fundamentals of energy flow. Energy flow Heat energy Light energy Chemical energy Chemical elements Bacteria, protists, and fungi

Ecosystems are supplied with a continual influx of energy from the sun and Earth’s interior. Is that enough? Student Misconceptions and Concerns Students are unlikely to have any prior knowledge of biogeochemical cycles. Although some transfers between the biotic and abiotic components of ecosystems, such as the use of fertilizer on plants, may be known to them, the broader fact that the biosphere is a self-cycling system is not appreciated by most students. Before you lecture, consider asking your students to explain how carbon, phosphorus, and nitrogen cycle through the atmosphere. Pre-testing your students on their knowledge can confirm both what they understand and what they may need explained to them in more detail. Teaching Tips As you discuss the importance of the biogeochemical cycles, consider explaining the basic label information provided on a container of plant fertilizer. Consider an example that might be used on houseplants, and therefore more likely to be familiar to students. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, which are essential chemicals for growth. Nope! So life on earth depends on the cycling of chemicals through the ecosystem. 5

The Major Earth Systems Geosphere – land, rocks, earth (Note: The surface land is called the lithosphere) Hydrosphere – water (oceans, lakes, rivers…) Atmosphere - air (78% N2, 21% O2) Biosphere – all living and decomposing organisms

Cycling between them

Biogeochemical Cycles Biogeochemical cycles is the flow of elements and compounds between biotic (living) components and abiotic (nonliving) components. * reservoirs (or sinks) Student Misconceptions and Concerns Students are unlikely to have any prior knowledge of biogeochemical cycles. Although some transfers between the biotic and abiotic components of ecosystems, such as the use of fertilizer on plants, may be known to them, the broader fact that the biosphere is a self-cycling system is not appreciated by most students. Before you lecture, consider asking your students to explain how carbon, phosphorus, and nitrogen cycle through the atmosphere. Pre-testing your students on their knowledge can confirm both what they understand and what they may need explained to them in more detail. Teaching Tips As you discuss the importance of the biogeochemical cycles, consider explaining the basic label information provided on a container of plant fertilizer. Consider an example that might be used on houseplants, and therefore more likely to be familiar to students. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, which are essential chemicals for growth. compartments that store matter 9

Water Cycle http://www.brainpop.com/science/earthsystem/watercycle/

Terms Evaporation – liquid to a gas from the surface of a liquid Condensation – gas collecting into clouds of water vapor Precipitation – rain, sleet, or snow Transpiration – evaporation of water from leaves ground water – water that has seeped underground Aquifer– water trapped and stored underground Run off – water that follows the slope of land down to rivers, lakes and oceans

Interesting Facts about Water There is a constant amount of water on and in the earth. Only 3% of the water is “fresh” 70% of fresh water is frozen in glaciers.

We have energy and water – now what nutrients do we need? Only about 24 elements! Six of them are macronutrients. The rest are micronutrients. Ex: Calcium, Magnesium We need them in large quantities!

CHNOPS What are the BIG SIX??? carbon hydrogen sulfur oxygen nitrogen phosphorus

Elements that make up Life!!

CARBON The Carbon Cycle CO2 C6H12O6

So what is carbon in the real world? Main ingredient in all organic molecules Used by plants in photosynthesis Used to compose carbon dioxide and all macromolecules Graphite or diamond! Can you name all three? Think back to Sports and Human Performance!

How do you think the levels of carbon stay in check in the environment? Photosynthesis The return of CO2 to the atmosphere by respiration closely balances its removal by photosynthesis. Respiration

Respiration

The Carbon Cycle Play the Carbon Cycle Game - http://www.windows2universe.org/earth/climate/carbon_cycle.html

The Carbon Cycle Continual movement of carbon atoms through organisms, oceans, atmosphere & crust Atmosphere as CO2 Biosphere as proteins, sugars, Hydrosphere Geosphere as CO2 As limestone fossils & fossil fuel

Where do we find the MOST carbon dioxide? 90% of Carbon Dioxide is stored in the ocean reservoir!

What disrupts this balance? The burning of fossil fuels! Combustion Reaction: CH4 + O2  CO2 + H2O Global Warming is a result of the excess CO2 in the atmosphere http://www.brainpop.com/science/earthsystem/carboncycle/

Nitrogen – The Nitrogen Cycle http://www.brainpop.com/science/earthsystem/nitrogencycle/ NH4+ NH3 N2 BACTERIA

Air (N2)  Nitrifying Bacteria  Plants  Animals  Decomposers  Denitrifying Bacteria  Air (N2)

Key Concepts Nitrogen in the soil (think fertilizer and manure) help plants grow. Plants get Nitrogen from the soil and excess nitrogen results in excess growth (to a point) Crop rotation keeps the nitrogen levels in the soil at healthy. Nitrogen is needed to make proteins – we get it by eating plants or eating animals that eat plants.

Bacteria are the Stars! Bacteria take the nitrogen out of the air and put it in the soil Other bacteria take the nitrogen out of the soil and puts it in the air Without bacteria there would be no nitrogen cycle.

What happens when humans disrupt the Nitrogen Cycle? Infertile land from using all the nitrogen up (this is why we have crop rotation) Acid Rain from polluting gases Algae blooms from fertilizer runoff into lakes and streams – These use up all the oxygen

Check for Understanding: Think, Pair, Share What would happen if all the decomposers went on “strike” and stopped working? Which cycles would it affect and how?

These biogeochemical cycles is part of what makes a planet habitable Connection to Space? These biogeochemical cycles is part of what makes a planet habitable EARTH: The most common elements in our atmosphere are nitrogen (78%), oxygen (21%), and argon (1%). The rest is comprised of very small amounts of neon, helium, methane, carbon dioxide, krypton, hydrogen, xenon, ozone, nitrous oxide, carbon monoxide, ammonia, and iodine. There is also water vapor in the lower part of Earth’s atmosphere. Venus has thick clouds of toxic CO2. Mars’s atmosphere is 95% carbon dioxide. The rest of it is nitrogen (3%), argon (1.6%), and very small amounts of water, methane, and oxygen. The gas giants have methane (CH4). “ices” – mixtures of compounds that include ammonia, ammonium, methane, and water. Read more: http://www.universetoday.com/35796/atmosphere-of-the-planets/#ixzz2KMkUkHrA