1. Intro to Freshwater Ecosystems

Question 1

Give 3 reasons why freshwater ecosystems are important to study

Answer 1

1. they’re good model ecosystems because they’re usually ~closed (minimal flow)
2. Understanding freshwater ecosystems helps us understand physics, chemistry, & geology (and vise versa- it’s all connected!)
3. Function & ecological services of freshwater ecosystems are very important

Question 2

Give 4 examples of the ecosystem function of freshwaters

Answer 2

• primary production vs:
• respiration… sources or sinks of CO2?
• secondary production: production of consumer biomass (eg fish)
• nutrient cycling (eg nitrogen)

Question 3

T/F

rivers are our only true renewable source of water

Answer 3

true!

lakes can dry up

Question 4

Intact freshwater systems are essential for potable water: rivers contain ___% of freshwater resources and not all of that is good quality

Answer 4

0.01%

Question 5

Irrigation is critical for food production, but there are two major costs that come with it:

Answer 5

1. water withdrawal & evaporation (waste)
2. pollution from pesticides and fertilizer

Question 6

__% of the world’s population lives in areas where water security or biodiversity threat exceeds the 75th percentile

Answer 6

80%
(as of 2000- probably higher now)
freshwater resources are very important!!

Question 7

T/F
Canada is very water abundant, but Alberta isn’t

Answer 7

true

Question 8

and
-

Answer 8

fisheries and recreation value (tourism)

Question 9

Sampling stratified lake waters is more complicated than sampling small streams or the mixed layer of a lake. How is it done?

Answer 9

• With a Van Dorn sampler (lowered into the water with a rope). This is used to sample anything at depth
• not for gas samples, measurements are taken with a probe

Question 10

Does oxygen form a polar or non-polar molecule? Does this make it have high or low solubility in water?

Answer 10

non-polar
low