Update Study_Sheet.md

Grade 9/Science/SNC1DZ/Study_Sheet.md

@@ -426,6 +426,13 @@ atmosphere, river to lake)
 - **Reshaping the geological features of Earth**
     - Erosion and sedimentation 
 
+### Human Inpacts
+- Humans building dams (flooding is a problem!)
+- Deforestation contributes to global warming, hence melting glaciers and causing flooding in cities
+- (Also less transpiration from clear cutting) – pg. 48
+- Factories and cars pollute the air, leading to acid precipitation
+- Oil spills destroy aquatic ecosystems
+
 ## Carbon Cycle
 - Fourth most abundant element in universe
 - Building block of all living things
@@ -436,8 +443,23 @@ atmosphere, river to lake)
 - CO<sub>2</sub> is a waste product of cellular respiration
 - Plants use carbon dioxide and water to form simple sugars (photosynthesis)
 - Light Energy -->  Chemical Energy
+- Carbon dioxide is `returned to the enviornment by:
+    1. `Resipiration` in plants, animals & micro-organisms.
+    2. `Decay` caused by micro-organisms (decompoers).
+    3. `Combustion` i.e. Burning fossil fuels.
+- **Phtosynthesis**
+    - CO<sub>2</sub> is converted to glucose using water and sunlight
+- **Cellular Respiration**
+    - Breaks down glucose to release energy, expel CO<sub>2</sub>
+- **Oceans are a HUGE carbon sink**.
 - <img src="https://www.news-medical.net/image.axd?picture=2017%2F6%2Fshutterstock_581980219.jpg" width="500">
 
+### Human Impacts
+- **Mining & burning fossil fuels**: Speed up release of CO<sup>2</sub> to the atmosphere.
+- **Deforestation & clearing vegetation**:  ↑ CO<sub>2</sub> in atmosphere.
+- **Acid rain**: release CO<sub>2</sub> from limestone.
+- CO<sub>2</sub> in the atmosphere is now higher than it has been in at least **800 000 years**.
+
 ## Nitrogen Cycle
 - The most abudant gas in the atmopshere (~78%)
 - `Nitrogen Fixation`: The process that causes the strong two-atom nitrogen molecules found in the atmopshere to break apart so they can combine with other atoms.
@@ -446,8 +468,10 @@ atmosphere, river to lake)
 - Atmopspheric nitrogen = N<sub>2</sub>
     - Most living organisms are `unable` to use this form of nitrogen
     - Therefore, must be **converted** to a usable form!
+    
+
 ### STEPS/PROCESSES
-- <img src="https://image.slidesharecdn.com/lab-11methodsforestimatingdenitrificationprocess-130414125752-phpapp01/95/lab11-methods-for-estimating-denitrification-process-4-638.jpg?cb=1365944316" witdh="300">
+- <img src="https://image.slidesharecdn.com/lab-11methodsforestimatingdenitrificationprocess-130414125752-phpapp01/95/lab11-methods-for-estimating-denitrification-process-4-638.jpg?cb=1365944316" witdh="100">
 
 ### Nitrogen Fixation
 - Most of the nitrogen used by living things is taken from the atmosphere by certain bacteria in a process called `nitrogen fixation`. 
@@ -456,6 +480,8 @@ atmosphere, river to lake)
 - Humans add nitrogen to soil through fertilizer
 - 3 ways nitrogen to get fixed
     1. Atmopheric Fixation
+        - Lightning Storms
+            - stroms and fuel burning in car engines produce nitrates, which are washed by rain into soil water. 
     2. Industrial Fixation
     3. Biological Fixation
         - 2 types
@@ -464,7 +490,14 @@ atmosphere, river to lake)
                 - Nitrogen changes into ammonium.
             2. Symbiotic Relationship Bacteria
                 - Bacteria live in the roots of legume family plants and provide the plants with ammonium(NH<sub>4</sub><sup>+</sup>) in exchange for the plant's carbon and a protected biome.
-             
+- `Nitrites` are absorbed by plant roots and converted to plant protein.
+- `Nitrates` **can be absorbed by other plants** to continue the cycle.
+- `Denitrifying bacteria` convert soil nitrates into N<sub>2</sub> gas
+    - This is a `loss` of N<sub>2</sub> from the cycle 
+
+### Human Impacts
+- Nitrates also `enters` the cycle **through the addition of nitrogen rich fertilizers to the soil** – made industrially from nitrogen gas (Eutrophication – pg. 60) 
+- Factories release NO compounds (acid rain)
 
 ## Nutrient Recycling
 - There is a `limited` amount of `nutrients` on earth
@@ -473,7 +506,14 @@ atmosphere, river to lake)
     - There are similar cycles for all nutrients.
 - When plants and animals die, their nutrient content is `not wasted`.
 - Bacteria and fungi decompose the remains and release the nutrients back into the abiotic environment (i.e. into the soil, nearby water and air).
+- Nutrients are then taken up by other plants and used to make new organic material.
+- This material is passed on down the food chains and is reused by all the chain members.
+- When death occurs for these members, the nutrients are again returned to the abiotic environment and the cycling of nutrients continues in this circular way.
+- This ensures that there is no real longterm drain on the Earth’s nutrients, despite millions of years of plant and animal activity.
 
+### Summary Of Nutrient Recycling
+- The way in which elements are continuously being broken down and/or exchanged for reuse
+- Occurs between the living and non-living components of an ecosystem.
 
 ## Benefits of Succession
 - Provides a mechanism by which ecosysmtems maintain their long term sustainability.