Lecture 12 - Factors Controlling Nutrient Cycling

Question 1

chemicals can come in two forms in the water based on their size. what are the two forms?

Answer 1

dissolved or particulate

Question 2

how do ions appear in lakes

Answer 2

land erosion

Question 3

solubility of ions depend on

Answer 3

temperature, pH and concentration of the ions in the water

Question 4

high temperature = _______ erosion

Answer 4

easy/fast

Question 5

concentration of ions/nutrients depend on

Answer 5

the amount the biota is eating/pooping

Question 6

acidity of water effects what?

Answer 6

controls mobilization of ions and impacts biological activity

Question 7

smoke stacks blow crap from the US to canadian waters - the Great Lakes and Northern canada waters. why is it that the northern canada waters were more affected by the smoke stacks (got more acidic)

Answer 7

great lakes = hard water = can buffer/bind up contaminants so less of an effect
northern canada lakes are soft water = low capacity to buffer

Question 8

turbidity definition and affected by what

Answer 8

turbidity = amount of light absorbed by water
affected by
- suspended particles
- presence of dissolved organic molecules

Question 9

suspended particles are ______ for bacteria and fungi

Answer 9

food

Question 10

redox potential determines ________ of water

Answer 10

chemical environment

Question 11

free P vs iron-phosphorus
which form can be taken up by microbes?

Answer 11

free P is available (unbound)

Question 12

redox potential is determined by

Answer 12

concentration of dissolved O2 (DO)

Question 13

amount of Dissolve O2 in water depends on

Answer 13

metabolic activity
temperature
diffusion / proximity to atmosphere

Question 14

cold water holds _____ (more/less) oxygen

Answer 14

more

Question 15

deep water holds _____ (more/less) oxygen

Answer 15

less

Question 16

consumption of DO in water by

Answer 16

respiration

Question 17

addition of DO to water by

Answer 17

photosynthesis

Question 18

when consumption outweighs addition of oxygen, leads to ______ conditions which is ____-saturated

Answer 18

anaerobic
sub

Question 19

when addition outweighs consumption of oxygen in a lake, this leads to ______ environment which is _____-saturated

Answer 19

oxygen-rich
super saturated

Question 20

photosynthesis done by primary producers. what factors control the rate of it?

Answer 20

light, temp, nutrients

Question 21

temperature and photosynthesis: rate of photosynthesis _____ with each ____ºC increase until _______

Answer 21

doubles
10ºC
threshold

Question 22

more nutrients = ____ rate of photosynthesis

Answer 22

increases

Question 23

water velocity ______ availability of CO2, and removes ________

Answer 23

increases

inhibitory chemicals

Question 24

respiration _____ with biomass

Answer 24

increases

Question 25

respiration ______ O2 levels

Answer 25

decreases

Question 26

respiration is controlled by

Answer 26

temperature and abundance of carbon

Question 27

if there’s a lot of primary producers in my backyard wetland, should the NPP be positive or negative

Answer 27

NPP = GPP - respiration so if hella GPP, NPP should be a positive because production outweighs respiration

Question 28

if NPP = -3, what does this mean

Answer 28

less carbon is being produced than consumed

Question 29

difference between NPP and NEP

Answer 29

NPP = net primary production NEP = net ecosystem production

Question 30

what time of the year does DO get depleted in hypolimnion of lakes and explain

Answer 30

when lake is stratified (summer and winter) stratified = low DO at bottom of lake because at bottom there’s more guys eating DO than making DO (and no mixing) most primary producers are at the top of the lake because easy access to light

Question 31

day-night variations of DO in a lake depend on

Answer 31

reaeration and biomass

Question 32

T/F: littoral zone of lake more likely to have DO all year round

Answer 32

true because littoral zone is top of lake so more likely for primary producers to be there so regardless of stratification they’ll always be chilling in littoral zone making DO for everyone

Question 33

fill in blanks with respiration and photosynthesis: during the day _____ dominates and at night _____ dominates in terms of the water being saturated with O2

Answer 33

photosynthesis respiration