week 2- oceanography

Question 1

what can scientists use satellites to do?

Answer 1

generate chlorophyll maps like this to analyse phytoplankton distribution

Question 2

how quickly does phytoplankton grow?

Answer 2

can grow explosively over a few weeks or even days and this is called a bloom. chlorophyll maps can only measure the surface chlorophyl

Question 3

what is the hydrological cycle?

Answer 3

involves the continuous circulation of water in the Earth-Atmosphere system. At its core, the water cycle is the motion of the water from the ground to the atmosphere and back again.

Question 4

what are the parts involved in the hydrological cycle and how long does water stay in each part?

Answer 4

• clouds: days
• ocean: 3,060 years
• soil: 600 years
• lakes:6.6 years

Question 5

water is a what?

Answer 5

solvent. the dipolar nature of the water attracts molecules together resulting in water surface tension

Question 6

why is water a solvent?

Answer 6

water molecules stick to other chemicals and reduce the attraction between their ions so they dissolve

Question 7

is water viscous?

Answer 7

yes and salt water has a higher viscosity then fresh water. so Speed in sea water requires a morphology that increases laminar flow through a fairly viscous and dense liquid.

Question 8

what two key features determine the
physical (and chemical) structure of the oceans

Answer 8

• temperature
• salinity
  (along with depth and pressure)

Question 9

what is the range in sea temperature?

Answer 9

-2 polar to 29 in costal seas

Question 10

which is denser warm or cold water? and fresh and saline water?

Answer 10

cold is denser and saline is denser

Question 11

what are the three distinct zones of ocean temperature?

Answer 11

• surface zone
• thermocline
• deep zone

Question 12

what is the surface zone?

Answer 12

mixed layer 25-500m depth mixed layer depth depends on mixing

Question 13

what is the thermocline zone?

Answer 13

( 200-1000m) rapid decrease in Temperature as a surface heat diffuses down and advection of cool water

Question 14

what is the deep zone?

Answer 14

(depth below 1000m) stable temperature around 1 degree

Question 15

thermocline + halocline = what

Answer 15

pycnocline

Question 16

thermocline definition?

Answer 16

an abrupt temperature gradient in a body of water such as a lake, marked by a layer above and below which the water is at different temperatures.

Question 17

Halocline definition?

Answer 17

vertical zone in the oceanic water column in which salinity changes rapidly with depth, located below the well-mixed, uniformly saline surface water layer.

Question 18

Pycnocline definition?

Answer 18

in oceanography, boundary separating two liquid layers of different densities.

Question 19

The ocean is stratified what does that mean?

Answer 19

ocean is made up of density layers or is stratified
* This stratification is a key determining factor to the nutrients supply and hence the phytoplankton distribution and blooms
* Mixing between layers of the ocean as heat slowly seeps deeper into the ocean by the action of currents, wind and tides
* Nutrients gets used up at the surface of the ocean
* High carbon at the surface as it is absorbed from atoms used up in photosynthesis

Question 20

what is the stratification of warm tropical seas like?

Answer 20

highly stratified surface layers decoupled from deep and quickly become nutrient depleted

Question 21

What is the stratification of polar waters like?

Answer 21

cool at surface so easier to pull water down from the surface so is less stratified

Question 22

what does the mixed layer seasonal cycle do?

Answer 22

The mixed-layer seasonal cycle has a strong impact on light and nutrient availability (phytoplankton are concentrated above the mixed later). Mixed layer generally deepens in winter due to wind mixing which eats away at the pycnocline. The result is a springtime
phytoplankton bloom driven by high nutrients, shallower mixing, increasing light, and warmer temperatures

Question 23

can salt water be drunk?

Answer 23

no

Question 24

what is salinity?

Answer 24

the total amount of solid inorganic material dissolved in seawater

Question 25

is it less or more salty in polar regions?

Answer 25

less salty due to ice melting fresh water into the sea and in warmer region there is more salt as there is more evaporation and less rain fall so less fresh water goes into the sea

Question 26

why is salt important for colder waters?

Answer 26

is key for the formation of deep waters that drives the oceans circulation

Question 27

what are the effects of salinity?

Answer 27

• density increases
• boiling point is elevated
• freezing point is lowered ie. why we put salt on roads

Question 28

how do we measure the salinity and temperature of the ocean measured?

Answer 28

the conductivity temperature depth rossette is used (CTD)

Question 29

what are ocean currents driven by?

Answer 29

driven by wind or part driven by global overturning circulation

Question 30

What is the ekman transport?

Answer 30

The earth rotates once a day and this imparts movement on the water bodies of the ocean this effects are strongest at the poles. Water and winds are deflected to the right in the northern hemisphere and to the left in the souther

Question 31

what is the Coriolis effect?

Answer 31

earths rotation determines current flow

Question 32

name some key currents?

Answer 32

• The gulf stream- the northerly loop of the north Atlantic subtropical gyre about 4mph and it carries warm water to the UK
• The Antarctic circumpolar current- it is the only current that circumscribes the whole earth and it connects all the ocean basics
• Pacific ocean circulation- two huge sub tropical gyres dominate the pacific with a dominate equatorial counter current due to its size

Question 33

why are currents and winds important?

Answer 33

Current and winds drive vertical upwelling (as well and horizontal flow), that replenishes surface nutrients to the euphotic zone