L1 Abiotic factors

Question 1

What is a measure of biomass and productivity in the ocean?

Answer 1

Chlorophyll a

Question 2

Where are areas of more and less chlorophyll?

Answer 2

Hotspots - coastal areas

Coldspots - Mid ocean

Question 3

What are the vertical ocean regions called?

Answer 3

Littoral - tidal zone
Neritic - above continental shelf
Oceanic - above continental slope and abyss

Question 4

what are the horizontal regions of the ocean called?

Answer 4

Epipelagic - surface waters
Pelagic - open ocean
Benthic - sea floor

Question 5

What is the best solvent?

Answer 5

Water

Question 6

What causes salinity?

Answer 6

River run off, volcanic activity
weathering of rocks - + ions
precipitation and hydrothermal vents - ions

Question 7

what is the ocean average salinity?

Answer 7

35%, varies btw 31-39%

Question 8

What instrument measures salinity?

Answer 8

Refractometer

Question 9

which area of oceans have the highest salinity and why?

Answer 9

when SW freezes, ions are excluded, so icebergs are almost pure and liquid water is saltier. In summer evens out slightly.
Also partially enclosed seas have high salinity, eg Red Sea

Question 10

which 4 ions are most abundant

Answer 10

Cl- 19.3%
Na+ 10.75%
SO4 2- 2.7%
Mg2+ 1.29%

Question 11

What unit is salinity measured in?

Answer 11

PSU - Practical salinity unit

Question 12

what are 3 important nutrients in the ocean?

Answer 12

Nitrate, Silicate and Phosphate

Question 13

What is a CTD meter?

Answer 13

Measures Conductivity, temp and density

Question 14

what can be used to trace a body of water?

Answer 14

SO6 -marker

Question 15

How much do day/night temperatures vary by?

Answer 15

<1 degree C

Question 16

What percentage of dissolved gas in the ocean is CO2 and O2?

Answer 16

80% CO2 (compared to 0.04% in air)

0-8ml/l of O2 compared to 210 in air.

Question 17

does cold or hot water have more O2 dissolved?

Answer 17

Cold

Question 18

2 ways to measure light penetration

Answer 18

Secchi disc

submersible photocells

Question 19

What is oxygen minima?

Answer 19

regions of the ocean with less available O2 than is needed for life

Question 20

What causes turbidity?

Answer 20

Phytoplankton and mineral particles

Question 21

name of zones with enough light for photosynthesis, enough light to see, not enough light to see

Answer 21

Photic/Euphotic
Disphotic/Dysphotic
Aphotic

Question 22

how is UV light cut out?

Answer 22

Salts absorbing it

Not absorbed in FW lakes or shallow SW

Question 23

at What depth is there most thermocline?

Answer 23

Intermediate depth, 200-1000m

Temp drops and Density increases

Question 24

When does salinity vary and when is it constant?

Answer 24

Varies in intermediate layers 200-1000m

Stays constant after 1000, as layers mix.

Question 25

Why do nutrients run out in summer? | How are they replaced?

Answer 25

Surface layers heat up, creating many small layers which dont mix, so nutrients cant be replenished from below. In autumn, surface cools and there is downwelling of nutrient low water, displaces deep rich water which rises. Over winter, waters mix and nutrients are replenished.

Question 26

Where does the Coriolis effect deflect currents to?

Answer 26

currents and winds deflected to the right in N hemisphere | To the L in southern hemisphere.

Question 27

How does the antarctic conveyor belt work?

Answer 27

Cold water at poles sinks and gets more dense. Movement of this deep cold water across globe.

Question 28

What is a gyre?

Answer 28

Major circular surface currents in indian, pacific and Atlantic oceans. Very low productivity in the centre.

Question 29

Descibe Ekman spiral

Answer 29

net movement of water is at 90 degrees to direction of wind. each layer moves in a slightly different direction

Question 30

What is ENSO?

Answer 30

El nino southern oscillation Years of abnormal weather patterns Increased SST with less/no upwelling reduced primary productivity

Question 31

What causes SST to rise?

Answer 31

High atmospheric pressure = less offshore winds = thermocline tilts less = no upwellings = higher SST

Question 32

example of El nino in Peruvian fisheries

Answer 32

Coastal upwelling usually supports lucrative fisheries. Run of low yieldsof anchoveta 1976 - 1985. These years had abnormally high SST.

Question 33

How do el nino years osscillate?

Answer 33

Oscillate between indian and pacific ocean. High pressure on one side = low pressure on other side

Question 34

Which was a bad el nino year and what were the consequences?

Answer 34

1977-8 Devastation both sides Fire, drought, tornadoes, famine, cyclones, hurricanes, heavy rainfall, mudslides, ice storms King penguin pop threatened by southern ocean warming

Question 35

Example of geo engineering

Answer 35

Iron fertilisation in HNLC areas eg Southern ocean. 2002 Early research shows stimulates growth of algae. change in species composition. Disregard of whole ecosystem response. Jellyfish bloom, Algae skeletons sink and cause widespread anoxia. NOC investigated widespread long term effects. found increased growth of Pseudonitchsia, produce Domoic acid.