1. Food Chains to Food Webs - Journals
Begin by writing/drawing your food chain down the middle of a page in your Environmental Science journal
After you’ve walked around the room, add at least 6 organisms from your classmates’ food chains
Additions must come from (at least) two different food chains.
Make a legend indicating which group (one name OK) the new organisms came from (see board)!
Be sure their level in the food web is accurately reflected!

2. Stream Chemistry and Modeling/Management
Unit 1: The Hydrosphere

3. Chemical Parameters for Streams
Dissolved Oxygen pH
Alkalinity
Phosphates/Nitrates
Chloride
Most are measured in ppm or mg/L
What is 1 ppm? ( or % as compared to water)
May not seem like a lot, but can mean life or death for many organisms

4. Dissolved Oxygen Review – absorbed through gills or skin
Dissolved oxygen is higher when…
More turbulence (mixing with the air)
Lower temperature
More photosynthetic organisms
Less organic pollution
Remember, plants use oxygen for cellular respiration too (levels can drop very low at night)

5. pH and Alkalinity
Review: pH has a unique scale of…representative of the concentration of Hydrogen atoms in solution
Determined by precipitation (acidic), other inputs, and alkalinity of the stream
Most prefer , will die at lower than 5
Alkalinity – ability of streams to buffer an acidic pH
Presence of a limestone (CaCO3) bedrock

6. Phosphates and Nitrates
Phosphorus – important nutrient for DNA and ATP (energy)
Phosphorus cycle – rocks break down and release phosphates (PO43-)
Nitrogen – important nutrient for DNA and proteins
Cycles through a variety of non-/useable forms via the Nitrogen Cycle
Too much of either can lead to eutrophication caused by runoff of manure and fertilizers, air pollution, and wastewater treatment discharge
We saw this runoff in our create your own watershed activity
Bad for humans too – if nitrate is too high in drinking water, bacteria in their digestive track can convert too much of it to nitrite which can hinder the blood’s ability to carry oxygen

7. Chlorides
Found to a greater extent in salt water (salts like NaCl dissolve)
Enter through weathering of minerals, industrial discharge, or runoff from farms or roads (de-icing compounds)
As you get closer to the sea, there’s more mixing between salt and fresh water
Organisms are adapted to only living on salt or fresh water

8. Modeling and Management
Will discuss and apply more after our test (?)
Studies often begin in the field, but eventually scientific models are used
Require simplifications and testing
Changes in management (which you can manipulate in a model) can be assessed in a model
Can take this data to governing bodies
What might be the downside of a model?

9. Stations Review Activity – to come before the test
Groups of 3 or 4 (no exceptions)
Move to the station, don’t bring the station to you
5 minutes per station – we will track
While you wait to move to the next station – how might this information be tested?
Take notes as you go!