Reservoirs - Physical boundaries or holding tanks (the ocean is a reservoir)
- A reservoir is also thought of by the mass of material in it, (the ozone, the fish in the ocean)
- You must be the one that defines a reservoir when doing your study, (the pesticides in a hawk is a reservoir)
Cycles Can Be Portrayed Visually, Graphically, or Mathematically
- When we construct a portrayal of the characteristics and functioning of a cycle or any characteristics of a cycle or any other environmental process, it's called a model
- Models of natural cycles and other processes can be:
- Physical models
- Landscape drawings
- Box models
- Mathematical models
- Landscape drawing
- Basic water cycle drawing
- Reservoirs are portrayed as boxes connected with arrows
- Even simpler cycle drawing
- Has units and %s along with the process on each arrow (Ocean evaporation 86% Atmosphere)
- Reservoirs -Boxes
- Contents - Numbers in that box
- Transfer processes - Arrows
- Fluxes - Numbers on the arrows
- Box models are the first step in developing math and computer models
- Each process is described by a math equation
The Content of a Reservoir is a Function of Both Concentration and Overall Size
Content (or burden) of a reservoir = total mass of substance in reservoir = concentration mass of physical unit
E.G. Content of Sodium in Sea Water
( concentration of seawater) (total mass of ocean)
(burden of Na in seawater)
Am I Going to Sample Every Fish in Lake Ontario? Once I Get a Fish, How Do I Find Mercury Content? (Put It In a Blender)
- There are not really any boundaries that exist on their own, we as researchers point out and make boundaries.
Fluxes are Flows of Matter Into and Out of Reservoirs
Flux - Amount of material transferred, described in terms of mass or volume per unit of time
- Evaporation of water from the ocean surface to atmosphere ~
- Fluxes are controlled by the rates of transfer processes and capacities of reservoirs
Source - Where the flux is coming from; a source gives out more than it takes in
Sink - Where the flux is going; a sink takes in more than it gives out
- If source - sinks steady state
Can a Source Also Be a Sink?
- Yes the atmosphere! (it evaporates water, and rain water)
- If the source and sink are running at the same rate it will stay the same
- How long will it take to use up a reservoir is a calculation?
- When source is way more than sink, it is called "burden is increasing"?
Turn over time - The time it takes to empty or fill a reservoir.
What if a Material of Interest Enters a Reservoir?
- Multiple possibilities
- Can go from source to sink (the amount of time it goes from source to sink is called residence time)
Positive Feedback - Self reinforcing, self perpetuating "vicious" cycle
Negative Feedback - Self regulating, homeostatic