currents + climate control

Question 1

what do ocean currents impact

Answer 1

huge impacts on nutrient, org, climate

Question 2

what are marginal seas

Answer 2

Major oceans (basins) have marginal seas (seas that are restrictive and open to the ocean. Can have different conditions) 
ex. Mediterranean sea

Question 3

what factors generate currents

Answer 3

The factors - wind and earth rotation

Question 4

how does wind impact currents

Answer 4

○ Trade winds - historically used as paths for ships
○ Higher sunlight at equator heats air
○ Air rises, moves to higer latitudes, and sinks as it cools
○ Drives planetary winds which drag over water- creates currents

Question 5

describe NE and SE winds

Answer 5

NE and SE trades blow
O to 30 deg. N/S lat.
NE trades blow SW
SE trades blow NW

Question 6

describe surface currents - wind

Answer 6

Surface currents 
pushed by wind 
move 450 to wind 
e.g. 450 to right NH 
450 to left SH.

Question 7

coriolis effect

Answer 7

force of earth’s rotation deflecting bodies (water/wind) located on it

Question 8

how can earths rotation impact currents - coriolis effect + ekmans transport

Answer 8

• Earth rotates west to east
• Coriolis affect increases down a water column bc of friction
○ Drag between water layerd increases deflection but water motion decreases with depth
○ Forms a narrowing spiral
○ At 90 m depth or 300’ from the wind - there will be no impact of the wind
○ Overall, below surface layers = current is 90 degrees from wind pushing it
○ Known as ekmans transport
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Question 9

what are gyres

Answer 9

Huge circular motions of surface water in ocean basins (due to global winds and coriollis) 
		○ e.g. gulf stream 
			§ Large gyre systems and rings 
		○ e.g. kuroshio current north pacific 
Affects phytoplankton numbers

Question 10

what are rings

Answer 10

• Rings ; satellite gyres form off main flow as it moves eastward in gyre
○ Can impact organism migrations
○ Rings can move organisms quite far as they move
§ e.g. cold core rings(nova scotia) head south
§ Warm core rings (florida) head north

Question 11

isolation via currents

Answer 11

• Southern ocean currents isolate antiarctica

Isolates the organisms and keeps them in those regions

Question 12

oceanic boundary currents

Answer 12

• Western sides of pacific/atlantic gyres

Strong currents; strong thermal boundaries; and motion creates high sea level at centers

Question 13

describe upwelling

Answer 13

• Combination of wind and coriolis effect
  
  • Bring water upward
  • Bring nutrients inshore and/or to surface - resupplying

Question 14

how is climate controlled - polar

Answer 14

• Polar waters remain cold/dense
• As they freeze, salt content remains making it sink
• sinking polar water pushes denser water ahead long ocean floors to equator
over years cold water spreads, mixing, eventually returning to surface.

Question 15

describe sea water density - measured, relationship w temp and h2o etc

Answer 15

Seawater density 
# of g/cm3 
@ increases with decreasing temp. & increasing 
salinity creates pycnoclines 
Normally 1.02 to 1.07 g/cm3 
solar penetrates about 
50m; wind mixes first 3- 
10m 
low density H20 rides on 
high density H20.

Question 16

what is pycnocline

Answer 16

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

Question 17

the great ocean conveyer belt

Answer 17

• Driven by density and wind moving heat of the planet (slow, not well understood)
  
  • Slowing down as the planet is warming

look at diagram

Question 18

describe el nino

Answer 18

means little boy - after christ child
upwelling of humboldt current normally brings nutrient rich waters
it slows down at a point (diagram) and warm water flows south
normally okay, but has a strong effect evry. 3-7 years
no winds drive water offshore

Question 19

how does el nino impact organism

Answer 19

•
• Warm nutrient poor water smothers the cold water - impacts the fish populations
• Generates waves of eastward moving warm water shutting down upwelling
• Anchovy numbers decline, collapse = birds die, water levels rise flooding the costal areas
Cascade effect - severe mortality in shellfish and coral (affected by temp and the food availability)

Question 20

what is El nino linked to

Answer 20

SO - seesaw system of high and low pressure
Nao - strong pressure different creates low water exchange, effecting atlantic ocean
• e.g. exchange between Swedish gullmar fjord and the open ocean
○ Organics build up
Low O2 effecting fisheries

Question 21

describe la nina

Answer 21

• Strong el nino often followed by la nina
• Equatorial easter pacific ocean becomes 3-5 degrees lower than normal - cooling affect
• Opposite effects of el nino - flooding in australia/ sri lanka
we are currently in la nina