Intro to chem: Dissolved oxygen

Question 1

At what concentration of oxygen are the waters considered hypoxic/ anoxic?

Answer 1

~2.3mg/L

Question 2

What impact does barometric pressure have on [DO] in lakes?

So what would be the difference between DO in an alpine vs valley lake? What about with depth?

Answer 2

Higher barometric pressure= increased [DO] in lakes

so, an alpine lake holds less DO than a valley lake (all else equal)

As you go deeper in a lake, [DO] will increase with the higher pressure

Question 3

T/F

Anoxia is more likely in systems that are cooler, more saline, or found at higher altitude

Answer 3

false

WARMER, more saline, or higher altitude

Question 4

T/F

Salinity suppresses DO levels

Answer 4

true

Question 5

How in turbulence mediated in streams vs lakes?

Answer 5

Lakes= wind
Streams= gravity and stream morphology (bed/bank)