Properties of water, light and oxygen

Question 1

Salinity of freshwater

Answer 1

Less than 0.5 PSU

Question 2

Salinity of marine water

Answer 2

greater than 35 PSU

Question 3

Zones in Aquatic environments (what is it and what are the organisms like?)
Pelagic zone

Answer 3

Open water

Organisms are planktonic

Question 4

Zones in Aquatic environments (what is it and what are the organisms like?)
benthic zone

Answer 4

bottom of the water body
Benthic organisms (crawlers, burrowers etc.)

Question 5

Zones in Aquatic environments (what is it and what are the organisms like?)
Littoral zone

Answer 5

Edge of the water body that has little wave action

Planktonic and attached organisms

Question 6

Zones in Aquatic environments (what is it and what are the organisms like?)
Rocky littoral zone

Answer 6

Edge of water body with high wave action of flowing water

Planktonic and attached

Question 7

Mixing regimes

Lotic waters

Answer 7

running water - organisms that are not attached will flow down the river

Question 8

Mixing regimes

Lentic waters

Answer 8

Standing water - strong currents around the perimeter

Question 9

How does water density influence aquatic plants?

Answer 9

water density is 1g/ml
aquatic plants do not need structural tissue or xylem and phloem
Plants grow quicker because less energy used

Question 10

what is the heat capacity of water and air?

what does this mean for aquatic environments?

Answer 10

water = 1000 cal/l
Air = 0.31 cal/l

temperature in water is more stable and only fluctuates by about 20 degrees celcius

Question 11

what is the relationship between temperature and density

Answer 11

density increases as temperature decreases

Question 12

what is a Homothermal water column

Answer 12

temperature is the same all the way down

Question 13

what is a stratified water column

Answer 13

water cannot mix so there are two separate circulations (the Epilimnion and Hyperlimnion, which are separated by the thermocline)
Organisms congregate at thermocline due to light and nutrient availability

Question 14

Types of stratification

Holomcitic

Answer 14

No stratification

Question 15

Types of stratification

Monomictic

Answer 15

stratifies once a year - if the heat from the sun is too strong the currents cannot mix the water enough - the size of epilimnion depends on temperature

Question 16

Types of stratification

Amictic

Answer 16

permanently stratified - all oceans

Question 17

what wavelengths are photosynthetically active radiation (PAR)

Answer 17

400-700nm

Question 18

Light

what is the Euphotic zone

Answer 18

between 1-100% light intensity - the only place plants can grow

Question 19

how is a secchi disk used to measure light penetration

Answer 19

it is a disk with white and black quarters - you lower it into the water until it can no longer be seen and record the depth - this is where there is less than 10% light penetration

Question 20

what travels further? blue of red light?

Answer 20

Blue light

Question 21

what is the oxygen diffusion coefficient

Answer 21

the speed that water diffuses - it is 800 times slower in water than in air - higher in cold water than warm water

Question 22

List the order of trophic statuses from the most nutrient poor to the most nutrient rich

Answer 22

Ultra-oligotrophic (>90%)
Oligotrophic
Mesotrophic
Eutrophic (0-40%)
Hyper-eutrophic (0-10%)