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!

Stream Chemistry and Modeling/Management Unit 1: The Hydrosphere

Chemical Parameters for Streams Dissolved Oxygen pH Alkalinity Phosphates/Nitrates Chloride Most are measured in ppm or mg/L What is 1 ppm? (0.000001 or 0.0001% as compared to water) May not seem like a lot, but can mean life or death for many organisms

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)

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 6.5-8.2, will die at lower than 5 Alkalinity – ability of streams to buffer an acidic pH Presence of a limestone (CaCO3) bedrock

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

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

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?

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!