The properties of water, currents and tides

Question 1

outline the structure of a water molecule

Answer 1

a negatively charged oxygen atom and 2 positively charged hydrogen atoms form a polar water molecule with electric attractions called hydrogen bonds

Question 2

outline how evaporation occurs

Answer 2

when molecules move fast enough it breaks free from all the hydrogen bonds and escapes from the liquid phase into the gaseous phase

Question 3

why is ice less dense than water

Answer 3

ice is less dense than water as the hydrogen bonds lock the water molecule into a fixed 3D lattice

Question 4

outline the property of heat capacity in regards to water and organisms in the water

Answer 4

the ability to absorb lots of heat for a with only a small increase in temp means the temp stays relatively stable so marine organisms aren’t subject to rapid changes in temp

Question 5

define heat capacity

Answer 5

the amount of heat needed to raise a substances temperature

Question 6

what is salinity

Answer 6

the total amount of dissolved salt in water measured in ppt

Question 7

how is salinity measured

Answer 7

via the conductivity of sea water, the more ions from the more salt mean electricity is passed through at a faster rate

Question 8

what determines the density of sea water

Answer 8

the temperature and salinity- water becomes more dense as it gets saltier and colder
temperature is the main controller of seawater density

Question 9

what are the most important gases in the ocean

Answer 9

oxygen
carbon dioxide
nitrogen

Question 10

what happens to sea water as temp and salinity increase

Answer 10

concentration of oxygen decreases

Question 11

why is co2 more soluble than oxygen

Answer 11

it reacts chemically when dissolved in water= the carbonate/bicarbonate buffer system

Question 12

outline how different wavelengths of light are absorbed by the ocean

Answer 12

shorter wavelengths of light are transmitted better so red is absorbed first and blue/green absorbed last

Question 13

what is the maximum depth light can penetrate the ocean

Answer 13

1000m

Question 14

what is the relationship between hydrostatic pressure and depth

Answer 14

it increases linearly

Question 15

what drives surface ocean currents

Answer 15

heat energy from the sun which causes winds

Question 16

what is the coriolis effect

Answer 16

the deflection of large scale motions such as winds and currents to the right in the northern hemisphere and to the left in the southern hemisphere
= instead of moving in the same direction as the wind, water moves at an angle of 45 degrees to the wind

Question 17

what are gyres

Answer 17

the result of wind driven surface currents forming a large, circular system called a gyre

Question 18

where do warm western currents move to

Answer 18

carry large amounts of solar heat from the equator to higher latitudes and cold currents flow in the opposite direction to the eastern side

Question 19

what influences currents on the continental shelf

Answer 19

the seabed
shape of coastline
tides

Question 20

what are the different layers in the ocean

Answer 20

1) surface layer = 100-200m
2) intermediate layer= 1000-1500m
3) deep layer= more than 1500m
4) bottom layer = contact with the seabed

Question 21

what is a permanent/main thermocline

Answer 21

a transition zone between warm surface water and cold water below

Question 22

what is a seasonal thermocline

Answer 22

formed in the temperate and polar latitudes in the spring and summer where the upper part of the surface layer is heated by the sun and then there is a sharp transition to cooler water below
the zone disappears when weather cools

Question 23

what are the main locations where water becomes dense enough to reach the bottom

Answer 23

• Atlantic ocean
• south of Greenland
• north of Antarctica

Question 24

define fetch

Answer 24

the span of open water over which wind blows. the larger the fetch the larger the size of waves

Question 25

what causes tides

Answer 25

the gravitational pull of the pool combined with the earths rotation