Science 10AP: Nutrient Cycles in Ecosystems

2.2E Nutrient Cycles in EcosystemsName:

Date:

(Refer to p. 68 – 91 of BC Science 10)

Nutrient Cycling in the Biosphere

Make some notes differentiating nutrients, stores and nutrient cycles.

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Metric measurement units used in the diagrams of nutrient cycles:

· gigatonne: _______________________________

· megatonne: ______________________________

**Complete Act. 2-2A Understanding Nutrient Cycles

The Effect of Human Activities on Nutrient Cycles

Make some notes the effect of human activities on nutrient cycles.

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What was Biosphere II?

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Energy Flow and Chemical Cycling through Ecosystems

(not in text book)

Energy flow occurs linearly, in one direction, through ecosystems. Energy enters from ______________ and exits as heat loss.

Most of the energy acquired by a given level of the food chain is used for respiration at that level and escapes in to the surrounding environment as ______________________________________. This energy is therefore unavailable to the next level of the food chain.

Label the diagram below to differentiate between chemicals cycling through a system and energy flowing.

The Carbon, Nitrogen, and Phosphorus Cycles

Which five elements limit life in ecosystems? ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Which of the five chemical elements are cycled between living organisms and the atmosphere?

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How does phosphorus enter the environment?

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Health of the ecosystem depends on a ______________________ of these five nutrients.

THE CARBON CYCLE.

· Every living thing contains ______________.

· Only _________% of the Earth’s crust is carbon.

How carbon is stored

Short term:

· ___________________________________________

· ____________________________________________

· ____________________________________________

· ____________________________________________

· ____________________________________________

Long term:

· ___________________________________________

· ____________________________________________

· ____________________________________________

· ____________________________________________

Define the following:

· sedimentation:

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· carbonate: __________________________________________________________

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Refer to THE CARBON CYCLE on p. 8 of your Data Booklet to answer the following.

1. The greatest carbon stores on earth: ___________________________________________________________________

2. The store that contains the least amount of carbon: ___________________________________________________________________

3. The greatest carbon exchange (in gigatonnes) and what is responsible : ___________________________________________________________________

4. The smallest carbon exchange (in gigatonnes) and what is responsible : ___________________________________________________________________

5. What process only releases carbon into the cycle? ___________________________________________________________________

How carbon is cycled through the ecosystem

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Photosynthesis

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The balanced chemical equation for photosynthesis is:

· Also occurs in some micro-organisms, such as _____________________________.

· Makes usable energy for __________________________.

· By eating plants, ___________________ obtain energy and take _______________ into their cells.

Cellular Respiration

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The balanced chemical reaction for cellular respiration is:

Create a diagram that illustrates the link between these two reactions.

Decomposition

The importance of decomposition in the carbon cycle: _____________________________________________________________________________________________________________________________________________________________________________________________________________________

Other ways carbon is cycled through ecosystems

· The following also play an important part in the carbon cycle, by releasing CO2 into the atmosphere:

· the oceans:__________________________________________________

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· volcanic activity:_____________________________________________

· decomposing trees: ___________________________________________

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· forest fires: _________________________________________________

HUMAN ACTIVITIES AND THE CARBON CYCLE

· Human activities have affected the natural carbon cycle in the following ways:

· Burning fossil fuels:

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· Land clearing/logging:

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The Nitrogen Cycle

Which macromolecules is nitrogen an important component of? ___________________________________________________________________________________________________________________________________________________________________________________________________

I. Proteins are made up of ________________ acids.

II. DNA is the abbreviation for _____________________________________

DNA is made up of many nucleotides.

View the Nitrogen cycle animation. It is very good.

http://www.mhhe.com/biosci/genbio/tlw3/eBridge/Chp29/animations/ch29/1_nitrogen_cycle.swf

How nitrogen is stored (textbook)

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How nitrogen is cycled through ecosystems

· ______% of the Earth’s atmosphere is nitrogen gas.

· Most organisms cannot use it in this form, so much of the nitrogen cycle involves ______ processes to make nitrogen available to plants, and then in turn to animals.

1. ________________________________________

2. ________________________________________

3. ________________________________________

1. Nitrogen Fixation: ________________________________________________

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Can occur in 3 ways:

1. In the atmosphere: _____________________________________

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· Compounds formed by _______ and _______ can enter soil through _______________________.

· Only small amounts

2. In the soil: ____________________________________________

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· Bacteria grow in root nodules and legumes.

· Symbiosis -> mutualism: plants get ____________, bacterial get _____________.

3. In water bodies: _______________________________________

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2. Nitrification: ___________________________________________________________

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· There are 2 stages involving nitrifying bacteria:

1. __________________________________________________________

2. __________________________________________________________

3. Uptake: _______________________________________________________

· These nitrogen compounds compose plant ______________.

· Herbivores and omnivores then eat plants, and use nitrogen for _________& ________________ _______________.

How nitrogen is returned to the atmosphere

Denitrification: ______________________________________________

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· denitrifying bacteria converted _____________ (______) back to ___________________ (____).

· Should be a _________________ between the amount of fixed nitrogen and nitrogen returned to the atmosphere.

· N2 is also returned to the atmosphere as ammonia (NH3) through _________________________________________________________

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How nitrogen is removed from ecosystems

· Excess nitrogen dissolves in ___________, enters the _______________________, and washes into _________and ____________.

· The nitrogen compounds eventually become trapped in ____________________________________, and will not be released again until the rock is ________________________.

HUMAN ACTIVITIES AND THE NITROGEN CYCLE

· Due to human activities, the amount of nitrogen in the ecosystem has __________________ in the last 50 years.

1. _______________________________________ and _________________________________ releases nitrogen oxide (NO) and nitrogen dioxide (NO2).

· Burning also releases nitrogen compounds that increase _____ ______________________ in the form of nitric acid (HNO3).

2. ________________________ often use large amounts of nitrogen-containing ______________________.

· Excess nitrogen is washed away, or leached, into the waterways.

· leaching: _______________________________________________________________________________________________________________________________________________________________________________________

· This promotes huge growth in aquatic algae = eutrophication: _______________________________________________________________________________________________________________________________________________________________________________________

Refer to THE NITROGEN CYCLE on p. 11 of your Data Booklet.

1. What two processes take nitrogen from the atmosphere and where do they occur? ________________________________________________________________________________________________________________________________________

2. Locate the two stages of nitrification. Name organism(s) and ions involved in the process.

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3. What is involved in uptake? List the ion(s) involved. ________________________________________________________________________________________________________________________________________

4. Locate denitrification on the data table. Name organism(s) and ions involved in the process.

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5. Locate and name another natural process that adds nitrogen to the cycle. ____________________________________________________________________

6. Locate and name two human activities that add nitrogen to the cycle. ________________________________________________________________________________________________________________________________________

The Phosphorus Cycle

Phosphorus is essential for _______________________ in plants and animals

Phosphorus is a part of the molecule that carries _________ in living cells.

· ______: adensosine triphosphate

· a special nucleotide that acts as the ‘energy currency of the cell’. Study this diagram to see what we mean by that:

Here you can see how energy is released from the ATP molecule when it is hydrolyzed to ADP and phosphate:

How is phosphorous used in plants? ___________________________________________________________________________________________________________________________________________________________________________________________________

How is phosphorous used in animals? ___________________________________________________________________________________________________________________________________________________________________________________________________

How phosphorus is stored

· Phosphorus is not stored in the ________________________.

· it is trapped in _______________________ (PO43–, HPO42–, H2PO4–) found in __________ (Earth’s Crust) and __________________________ in the ocean.

Refer to THE PHOSPHORUS CYCLE on p. 9 of your Data Booklet.

1. List the five phosphorus sinks, in order, from largest to smallest? ____________________________________________________________________________________________________________________________________________________________________________________________________________

How phosphorus is cycled through ecosystems

Weathering: _____________________________________________________

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Differentiate chemical weathering and physical weathering:

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· Weathering doesn’t occur until there is geological uplift.

· Geological uplift: __________________________________

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Refer to THE PHOSPHORUS CYCLE on p. 9 of your Data Booklet.

1. List the eight processes, in order, from largest to smallest involved in the flow of phosphorus in the phosphorus cycle? ____________________________________________________________________________________________________________________________________________________________________________________________________________

HUMAN ACTIVITIES AND THE PHOSPHORUS CYCLE

Human activities can either add excess phosphorus to the ecosystem or reduce the phosphorus supplies in the ecosystem.

· Add excess phosphorus:

· Mined for commercial fertilizers and detergents

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· Reduce phosphorus supplies:

· Slash-and-burn practices

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HOW CHANGES IN NUTRIENT CYCLES AFFECT BIODIVERSITY

· Any significant changes to any of these nutrients (____, _____, ____, _____, and _____) can greatly impact the health and biodiversity in an ecosystem

1. Carbon: contributing to _______________________

· _______________ carbon in the atmosphere, slight temperature changes and changes in water level can all affect ecosystem biodiversity

· If one part of the ecosystem is affected/removed, it affects the rest of the food chain/food web.

2. Nitrogen: can seriously affect __________ biodiversity

· Some plants better adapted to ______________ nitrogen levels than others and therefore out complete the less tolerant species.

3. Phosphorus: can affect _______ _________

· _________________ phosphorus have reduced algae production in some lakes, which is an important food source for _________________.

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