Into the Abyss

Question 1

How is the ocean stratified?

Answer 1

by density (warm and fresh= less dense than saline and cold)

Question 2

what is the thermocline

Answer 2

thin layer in body of water where there is a rapid drop in temperature with depth

Question 3

what is the pycnocline

Answer 3

thin layer where there is a rapid increase of density with depth

Question 4

what is the dominant control on density

Answer 4

temperature

Question 5

other than temperature, how can water change in density

Answer 5

exchanging of material to another body of water

Question 6

explain the origins of salinity

Answer 6

streams carry dissolved substances to the sea-> made of cations from exposed crustal rock and anions likely from the mantle

Question 7

how can the concentration of dissolved materials change?

Answer 7

addition or removal of freshwater due to rates of precipitation and evaporation

Question 8

what is the halocline

Answer 8

a thin layer of water where there is a rapid change of salinity with depth

Question 9

how can one track how two water masses mix with each other?

Answer 9

see how their characteristics change

Question 10

give three depth layers in the ocean

Answer 10

surface zone/mixed layer, thermocline/halocline/pycnocline, deep zone

Question 11

what percentage of the ocean’s volume is in the deep zone?

Answer 11

80%

Question 12

at what latitudes is the deep zone in contact with the atmosphere?

Answer 12

high latitudes

Question 13

to what depth is plant and animal life restricted?

Answer 13

200m (photic zone)

Question 14

what is calcareous ooze and where can it be found

Answer 14

layers of muddy, calcium carbonate bearing soft rock sediment on the seafloor, low to mid latitudes

Question 15

what organisms are favoured by warm surface water and why

Answer 15

carbonate secreting organisms, not found in deeper water due to acidity

Question 16

name the largest body of polar surface water

Answer 16

antarctic circumpolar water, extends to the ocean floor

Question 17

roughly what depths are upper water masses at?

Answer 17

550-1500m

Question 18

where and how are deep and bottom water masses formed?

Answer 18

cold polar seas, cold winds cool water and cause it to sink

Question 19

how is north atlantic deepwater formed?

Answer 19

intense surface cooling and convective overturning-> becomes trapped in basins, overflows ridges and disperses

Question 20

how is antarctic bottom water formed?

Answer 20

cold winds and sea ice cool cool surface water as cold as possible without freezing, mixes with dense brine and sinks to deep ocean

Question 21

what is a gyre?

Answer 21

large subcircular ocean system made up of major ocean currents

Question 22

why is the centre higher than the periphery in the NA ocean gyre>

Answer 22

converging currents force it upwards

Question 23

explain the motion of currents in a gyre

Answer 23

coriolis effect and the pressure gradient balance and create a system in dynamic equilibrium so that water flows across rather than down the slope-> geostrophic currents

Question 24

what are warm and cold core rings?

Answer 24

meanders in currents like the gulf stream

Question 25

by what measure is the speed of thermohaline circulation measured

Answer 25

metres per day

Question 26

where do deep waters enter and leave the surface current system?

Answer 26

southern ocean

Question 27

why would the breakdown of thermohaline circulation alter climate?

Answer 27

thermohaline circulation is an important transporter of heat

Question 28

what determines the solubility of gas?

Answer 28

partial pressure: more soluble when water is cold, fresh and under high pressure

Question 29

how are the oceans ventilated

Answer 29

oxygen rich water sinking

Question 30

what gas is very soluble

Answer 30

CO2