1. Nitrogen Cycle A. Nitrogen Facts  Makes up DNA & proteins (muscle function). (muscle function).  Help plants grow. Where Nitrogen is Found (store):  Atmosphere (78% is N 2 )  Oceans  Organic matter in soil  Lakes, marshes, organisms

2. 1 4 3 2 4 1

3. B. How Nitrogen Changes Form: - N 2 is not usable by plants or animals, so it has to be converted to other forms. -Plants can use NO 3 - (nitrate) and NH 4 + (ammonium) Part I. Making nitrogen into usable form (3 steps) 1.Nitrogen Fixation  process in which nitrogen gas (N 2 ) is converted into a compound that contains ammonium (NH 4 + ) or nitrates (NO 3 - )  Occurs in 3 ways:  Atmosphere:  Soil: N 2  NH 4 + (Nitrogen fixing bacteria eg. Rhizobium)  Water: N 2  NH 4 + (Cyanobacteria) N 2  NO 3 - (lightening) Not in the Data Booklet

4. 2.Nitrification  done by nitrifying bacteria.  2 Stages:     3. Uptake  The process of taking up usable nitrogen by plants and incorporated into plant DNA  NO 3 - is sucked into plants & used for growth.  Herbivores eat plants & use N for making proteins & DNA. Step 1 NO 3 - (nitrate) NH 4 + (ammonium)NO 2 - (nitrite) Step 2

5. Part II. Return N 2 to ecosystem 1.Denitrification   done by denitrifying bacteria & volcanic eruptions  NO 3 -  N 2 2. Decomposition:   nitrogen from DNA/protein of dead organism  NH 4 + (Bacteria and Fungi) 3. Volcanic Ash:   Return ammonia (NH 3 ) to atmosphere

6. C. Human activities affect the nitrogen cycle. 1.Burning fossil fuels + Land clearing ► NO & NO 2 produced  lead to Acid Rain  lead to Acid Rain Question: Leaching of nitrogen into water ways, what problem could this make?

7. Algal Bloom 2. Overfertilization  NH 4 + & NO 3 - leach into soil & waterways. ► huge growth in aquatic algae = eutrophication  Algal blooms use up all CO 2 & O 2, blocking sunlight and therefore kill many aquatic organisms.  Algal blooms can produce neurotoxin that poison the animals

8. The Phosphorous Cycle Phosphorous Facts  In Plant, Phosphorous contributes to root growth, stem strength and seed production.  In animals/human, phosphorous is important for bone development and DNA. Where Phosphorous is Found (storage):  Found in phosphate rocks (PO 4 3–, HPO 4 2–, H 2 PO 4 - ) and sediments on the ocean floor; Not in the Atmosphere

9. The Phosphorous Cycle * * 1 2 * 3 * 4 5 6 6 7 8 9 10 11 12 13 * * * *

10. B. How Phosphorous Changes Form. 1.Weathering (breaking down rock into smaller pieces). a) Chemical weathering (Chemical reaction) : acid rain or lichens releases phosphates (PO 4 3- ) acid rain or lichens releases phosphates (PO 4 3- ) b) Physical weathering (physical process) : wind, water and freezing release the phosphates. wind, water and freezing release the phosphates. 2.Uptake: plants suck up PO 4 3-, then are eaten by animals. 3.Decomposition: Bacteria break down organic matter & phosphorous is returned to soil. phosphorous is returned to soil. 4.Geologic Uplift: when rocks under the ground are pushed up  mountains  weathering (mountain building).

11. C. Human activities affect the Phosphorous Cycle. 1. Fertilizer, P-containing detergents, animal waste (bird’s dropping or guano),industrial waste, untreated human waste add additional phosphate to the phosphorous cycle. dried excrement of fish-eating sea birds, deposited in rocky coastal regions 2. Guano: dried excrement of fish-eating sea birds, deposited in rocky coastal regions Q. How much phosphorus does guano contribute to the phosphorus cycle? 2. Too much phosphorous can cause death in some animals (Eutrophication)

12. How Changes in Nutrient Cycles Affect Biodiversity To Review: Any significant changes to any of these nutrients (C, H, O, N or P) can greatly impact biodiversity. 1. Carbon cycle changes  climate change & global warming. 2. Too much nitrogen can allow certain plant species to out-compete other species. 3. Decreased levels of phosphorous  slow growth of algae (important producers).

13. ► Homework: Pg 91 # All ► Handout from yesterday. ► Chapter 2 Test on Friday.