i.circulation a.coriolis effect affects motion of winds, currents and tidesaffects motion of winds,...

I.I. CirculationCirculation

A.A. Coriolis EffectCoriolis Effect• Affects motion of winds, currents and Affects motion of winds, currents and

tidestides• Caused by rotation of earthCaused by rotation of earth• N. Hemisphere – Deflects motion to rightN. Hemisphere – Deflects motion to right• S. Hemisphere – Deflects motion to leftS. Hemisphere – Deflects motion to left

Fig. 3.18


B.B. Wind PatternsWind Patterns• Driven by solar heatingDriven by solar heating• Modified by rotation of earth (Coriolis Modified by rotation of earth (Coriolis

Effect)Effect)• Trade windsTrade winds (0–30 (0–30oo latitude) - Steadiest latitude) - Steadiest

• DoldrumsDoldrums (Equator) (Equator)• WesterliesWesterlies (30–60 (30–60o o latitude)latitude)

• Horse latitudesHorse latitudes (30 (30oo latitude) latitude)• Polar easterliesPolar easterlies (60–90 (60–90o o latitude) – Most variablelatitude) – Most variable

Fig. 3.19

Fig. 3.20


C.C. Surface CurrentsSurface Currents• Driven by windsDriven by winds

• Surface currents deflected to right/left of wind Surface currents deflected to right/left of wind direction by Coriolis Effectdirection by Coriolis Effect

Fig. 3.21




• AnticyclonicAnticyclonic gyres in major basins gyres in major basins• Clockwise in N. HemisphereClockwise in N. Hemisphere• Counterclockwise in S. HemisphereCounterclockwise in S. Hemisphere• Used in navigation by early sailorsUsed in navigation by early sailors

Fig. 3.22




• AnticyclonicAnticyclonic gyres in major basins gyres in major basins• Clockwise in N. HemisphereClockwise in N. Hemisphere• Counterclockwise in S. HemisphereCounterclockwise in S. Hemisphere• Used in navigation by early sailorsUsed in navigation by early sailors

• Currents transport heat from equator to Currents transport heat from equator to polespoles

• Why is Antarctica covered with ice today?Why is Antarctica covered with ice today?

• Surface temperatures higher on western Surface temperatures higher on western margins of ocean basins margins of ocean basins vs.vs. eastern margins eastern margins

Fig. 3.23


D.D. WavesWaves• Surface waves produced by wind blowing Surface waves produced by wind blowing

across water (friction)across water (friction)• StructureStructure

• CrestCrest – Highest part – Highest part• TroughTrough – Lowest part – Lowest part• WavelengthWavelength – Distance between crests – Distance between crests• PeriodPeriod – Time between crests – Time between crests

Fig. 3.24



across water (friction)across water (friction)• StructureStructure• Size related to wind speed and Size related to wind speed and fetchfetch

Fig. 3.26



across water (friction)across water (friction)• StructureStructure• Size related to wind speed and Size related to wind speed and fetchfetch• Seas Seas Swell Swell Surf Surf

• Surface usually Surface usually confused swellconfused swell• Crest + trough cancelCrest + trough cancel• Crest + crest reinforceCrest + crest reinforce

Fig. 3.27


E.E. TidesTides• FactorsFactors

• Rotation of earthRotation of earth• Gravitational influence of moonGravitational influence of moon• Gravitational influence of sunGravitational influence of sun

Fig. 3.29




• Full cycle = 24 hours 50 minutes (Full cycle = 24 hours 50 minutes (Why?Why?))

Fig. 3.30




• Full cycle = 24 hours 50 minutesFull cycle = 24 hours 50 minutes• Spring tidesSpring tides – Moon and sun reinforce – Moon and sun reinforce• Neap tidesNeap tides – Moon and sun don’t reinforce – Moon and sun don’t reinforce

Fig. 3.31




• Full cycle = 24 hours 50 minutesFull cycle = 24 hours 50 minutes• Spring tidesSpring tides – Moon and sun reinforce – Moon and sun reinforce• Neap tidesNeap tides – Moon and sun don’t reinforce – Moon and sun don’t reinforce• PeriodPeriod

• SemidiurnalSemidiurnal – N. America (E. Coast), Europe, Africa – N. America (E. Coast), Europe, Africa• MixedMixed – N. America (W. Coast) – N. America (W. Coast)• DiurnalDiurnal – Antarctica, Caribbean, Gulf of Mexico, – Antarctica, Caribbean, Gulf of Mexico,

PacificPacific

Fig. 3.32

Fig. 3.33


F.F. Vertical CirculationVertical Circulation• EddiesEddies• Thermohaline circulationThermohaline circulation

• Driven by unstable water column with denser Driven by unstable water column with denser water at surfacewater at surface

• Drives Drives Great Ocean ConveyorGreat Ocean Conveyor

Fig. 16.3

II.II. Challenges of Life in the SeaChallenges of Life in the Sea

A.A. SalinitySalinity• Enzymes and other organic molecules Enzymes and other organic molecules

sensitive to changes in concentrations of sensitive to changes in concentrations of dissolved ionsdissolved ions

• Marine organisms live in medium Marine organisms live in medium containing dissolved ions that can affect containing dissolved ions that can affect their biologytheir biology

1.1. Diffusion and OsmosisDiffusion and Osmosis• In solution, molecules move randomly and tend In solution, molecules move randomly and tend

to migrate from regions of higher concentration to migrate from regions of higher concentration to regions of lower concentration (to regions of lower concentration (diffusiondiffusion))

Fig. 4.12

II.II. Challenges of Life in the SeaChallenges of Life in the Sea

A.A. SalinitySalinity1.1. Diffusion and OsmosisDiffusion and Osmosis

• Diffusion problematic – leads to loss of important Diffusion problematic – leads to loss of important ionsions

• Selectively permeable cell membrane limits Selectively permeable cell membrane limits movement of certain molecules (large, electrically movement of certain molecules (large, electrically charged) but allow movement of small molecules, charged) but allow movement of small molecules, e.g.e.g. water water

• OsmosisOsmosis – Diffusion of water across selectively – Diffusion of water across selectively permeable membranepermeable membrane

• Water diffuses from region of higher water Water diffuses from region of higher water concentration (lower salt concentration) to concentration (lower salt concentration) to region of lower water concentrationregion of lower water concentration

• Possible to move molecules against Possible to move molecules against concentration gradient by using energy to power concentration gradient by using energy to power active transportactive transport

Fig. 4.13

i.circulation a.coriolis effect affects motion of winds, currents and tidesaffects motion of winds,...

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