Lesson Notes: Nitrogen, Carbon and Phosphorus get recycled through living things.

Read the Study guide and do questions from pages 33 to 42 
Read and make notes on section 2.2 of your textbook.  

Assignment:  draw a cartoon of the Nitrogen cycle OR the carbon cycle in a simplified form.

NUTRIENT CYCLE NOTES            section 2.2                                                                   

Why do living things need

Nitrogen in their bodies?                  Nitrogen is part of the amine group in an amino acid.  Amino acids are

building blocks of protein and protein are building blocks for many structures in living things.  Within your body, proteins form enzymes, pigment, muscle, cellular components.   Animals have protein as a major structural component. 

How much Nitrogen is in the atmosphere?     about 80% of air is nitrogen and the other 20% is oxygen. This nitrogen is necessary for survival for all life on earth, yet most life forms are unable to access the nitrogen without help from microbes.

How do PLANTS AND ANIMALS

access atmospheric nitrogen? They cannot do it alone.                               
PLANTS AND ANIMALS MUST ACCESS NITROGEN  IN A COMPLEX,     ROUNDABOUT WAY THAT DEPEND UPON BACTERIA.        

here are the four steps: 
                          STEP 1:  NITROGEN FIXATION:  NITROGEN GAS MUST TURN INTO  AMMONIUM

N_{2 gets turned into} NH₄⁺ 

At the NH4 stage, plants are able to absorb this and use it for life functions but animals (including humans cannot – unless you believe those people who like to drink pee for nutrition)

a.     in soil:  nitrogen fixing bacteria in roots These bacteria live as symbionts in the roots of plants such as legumes (beans), clover..  Examples of nitrogen fixing bacteria  living in roots is Rhizobium..

b.     An aquatic example is Cyanobacterium

                                                             STEP 2: AMMONIUM IS TURNED INTO NITRITES AND NITRATES by NITRIFYING BACTERIA in the soil:   

NH₄⁺ gets turned into NO₃^-:  
ammonium turns into nitrates

STEP 3: Both Ammonium and NITRATES CAN NOW BE ABSORBED by  PLANTS through their roots:

Plants take the nitrate and turn it into plant proteins

STEP 4:  PLANTS ARE EATEN BY ANIMALS

When animals eat plants, the plant protein are converted into animal protein.  

Are there other sources of nitrogen without following those steps?    There are three other sources:
1.  When animals and plants die, their bodies decompose into AMMONIUM Microbes and fungi and other DECOMPOSERS are responsible for this 
2.  When animals urinate in the environment, urine breaks down into AMMONIUM

3.  Lightening strikes can make nitrates  in the soil .     

What would happen if Rhizobium, Cyanobacteria and all

Those nitrogen fixers became extinct?   

                                                            First plants would die from lack of nitrogen and then all the animals would die.  We depend on the nitrogen fixers to make our protein.  (you are protein, when you stop to think about it…)

How is nitrogen returned back to the atmosphere? DENITRIFICATION:  again a task performed by bacteria:  the denitrifying bacteria. 

EUTRIFICATION:                                     too much of a good thing  nitrogen is essential so more nitrogen is better right?  Wrong.  Human industry and agriculture can release ammonia into the environment (a lake) and cause algae to bloom. Algae grows quickly and then dies all at once, robbing the lake of oxygen. Fish die as a result. 

Images to remember                                Copy fig 2.35 and 2.37 in words p. 80 and 81 in your textbook

CARBON CYCLE

Carbon cycled throughout the earth’s history                                                                                                                                             The Carbon dioxide you are breathing out now could have contained carbon  from Isaac Newton’s teacup  and the same one that entered a prehistoric plant through  photosynthesis. The carbon emitted from a car was photosynthesized by an aquatic plant millions of years ago.  Carbon on earth never really disappears.  It just gets used over and over again. 

Carbon cycles through these places                      
1.  atmosphere in the form of carbon dioxide:  CO2

                                                                                         
2. Plant material:  cellulose, starch

                                                                                          
3. Animal material:  carbon is in our fat and protein. 

                                                                                        
4. Shells of phytoplankton:  calcium carbonate shells

                                                                                          
5. Dissolved in the ocean:  as carbonic acid

Atmospheric carbon has sources and sinks :           

a sink removes carbon dioxide from the atmosphere.  
A source returns carbon back to the atmosphere.

Examples of Carbon sinks

1.     PLANTS, especially forests and

 bogs    THROUGH PHOTOSYNTHESIS     

                                                            CO₂ + H₂O    ^sunlightà   C₆H₁₂O₆ + O₂

                                                Also fossilized plants: 

3.  atmosphere to the ocean         carbon dioxide gets absorbed into the ocean and turns into carbonic acid.  This acid is a buffer.  The buffer has a tendency to maintain ocean acidity at a constant level

4. ocean to phytoplankton shells   the bicarbonate ion  HCO₃^- can combine with calcium to make calcium carbonate CaCO₃ shells for a variety of sea life, including phytoplankton.  This carbon can be locked up for millions of years as the sea life dies and turns into limestone cliffs.

Examples of Carbon sources:

1. animals breathing: cell respiration
2. plants and animals dying and releasing carbon dioxide 
3.  fossil fuel combustion:           

                                                C₆H₁₂O₆ + O_{2  -->}   CO₂ + H₂O

PHOSPHORUS CYCLE

PHOSPHORUS is used for             1. energy:  part of adenosine triphosphate, an energy molecule

                                                             2.  Makes genetic material:  DNA and RNA

                                                            3.  In vertebrate animals:  makes bone

                                                            4.  In plants: promotes growth

PHOSPHORUS CYCLE                             FROM LIVING THINGS TO THE SOIL AND BACK AGAIN. 

                                                            Phosphate is trapped in rocks, sediments, ocean floor

                                                            Weathering releases phosphates

EUTRIPHICATION                           humans add phosphorus to the environment resulting in algal blooms and fish death

  
Water and Carbon Cycle Crash Course