Lecture 1; Rivers and lakes

Question 1

what does density vary with in water?

Answer 1

temperature and salinity

Question 2

what is velocity?

Answer 2

the resistance of a fluid to something moving thorugh it

Question 3

what is roughness?

Answer 3

property of an organism or bed of a stream in contact with the fluid of water flowing over it

Question 4

what does roughness increase with?

Answer 4

size and velocity

Question 5

which freshwater system is depth more important in?

Answer 5

lakes

Question 6

What forces impact larger objects?

Answer 6

pressure > drag

Question 7

what forces impact medium objects?

Answer 7

pressure and drag both important

Question 8

what forces impact small objects?

Answer 8

drag and viscosity

Question 9

Reynolds number equation

Answer 9

density x velocity x length / viscocity

Question 10

what is Reynolds number?

Answer 10

ratio of pressure forces to drag forces

Question 11

does flow increase downstream and why?

Answer 11

yes due to more inputs pf water form the catch,ent

Question 12

lotic?

Answer 12

rivers as flowing systems

Question 13

lentic?

Answer 13

lakes as standing waters

Question 14

name 3 sources of energy to the stream

Answer 14

• sunlight (SW radiation)
• LW radiation
• connection from river to air above

Question 15

Hyporheic

Answer 15

below river bay

Question 16

what is more variable, air or water temperature?

Answer 16

Air is more variable

Question 17

when does relationship between air and water temperature not exist?

Answer 17

when water freezes

Question 18

Frazil ice

Answer 18

small mobile ice

Question 19

Anchor ice

Answer 19

solid ice which can’t move

Question 20

coldest form of streams?

Answer 20

glacier fed stream

Question 21

most variable streams?

Answer 21

streasms receiving snowmelt as runoff

Question 22

average temperature tends to increase as we go downstream?

Answer 22

TRUE

Question 23

why small streams more stable?

Answer 23

dominate by one type of source

Question 24

riparian vegetation?

Answer 24

vegetation growing alongside of river (30m)

Question 25

effect of riparian veg on stream?

Answer 25

• creates more shade

- decrease temp as blocks out sunlight

Question 26

what increases DO in freshwaters?

Answer 26

• photosynthesis
• turbulence
• more surface are

Question 27

DO and water temp relationship?

Answer 27

• inverse relationship

- cold water can hold more DO

Question 28

polar and covalent compounds relationship with temperature?

Answer 28

• polar; positive

- covalent; negative

Question 29

When is DO less soluble n water?

Answer 29

in warmer temperatures

Question 30

DO levels for egg development?

Answer 30

> 0.5mg/l

Question 31

co2 + H2o =

Answer 31

H2CO3 (carbonic acid)

Question 32

when does co2 dissolve more?

Answer 32

when temp increases

Question 33

rainwater pH?

Answer 33

5.64

Question 34

buffering is…

Answer 34

effect of small changes that inputs of acids will have on a small river or lake

Question 35

buffering is caused by

Answer 35

natural carbonates and bicarbonates

Question 36

source of phosphorous?

Answer 36

weathering of phosphate bearing rocks

Question 37

phosphorus cycle?

Answer 37

• sourced from p rocks
• becomes lake sediment
• dissolves into imorganic phosphate
• plant and bacteria convert it into organic posphate

Question 38

in natural waters, what is the N;P ratio?

Answer 38

6:1

Question 39

allochotonous carbon

Answer 39

from outside the system

Question 40

autochtonous carcbon

Answer 40

from within the system