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40 Cards in this Set
- Front
- Back
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oceans |
store of carbon dioxide, come CO2 drawn into ocean, becoming more acidic - effecting marine life (coral) |
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thermohaline |
zone where temperature changes most rapidly temperature gradients |
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5 oceans |
Pacific - largets, 3.9km deep, rocks <2Ma, old west Atlantic 0 3.3 Km deep, 15 Ma, oldest from ridge Arctic - basically landlocked (Siberia, Canada, Alaska) - deep water convection from Atlantic ocean to north Atlantic = from strait - 14 mil km^2 South ocean - circumpolar ocean Indian ocean |
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seas |
oceans divided into seas - shallow areas underlaid by continental shelf, depth 10s-4-500m deep ex. Basalt shelf under sea, north Alaska/Canada |
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hypsometric curve |
a statistical summary of the average elevation of different parts of the earth x-axis - cumulative area as a % of total surface area of the earth y-axis - elevation above and below sea level |
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highest mountain |
everest - 8.8km |
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average elevation of continent |
5 km |
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deep ocean flor depth |
3-5km |
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ocean trench |
deepest marianus trench 11km western Pacific |
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releif |
20km from highest land to the deepest trench |
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oceans occur |
ocean form basin - oceanic crust and t=ltiohphere below is denser that that below continent basaltic and babrors underlie oceanir while metamrohpic and igneous lie under continetal rock under oceanis denser due to higher concentrations of iron and magnesium |
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physical characteristics |
mid0atalntic ridge (mountain chain trough) ridge displaced transform fault abyssal plain - 3-5km deep continental rise continental slope continetal shelf break oceanic island (cape verdi_ seamount and guyots |
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pelagic sedimentation |
sediment increases as it furthers from axis of the mid-Atlantic ridge drape of sediment - insight to climate change 0 sedimentary cores (1m) largely silt and clay - occasionally small pebble layer 1-2mm |
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types of pelagic sediment |
terrigenous - silt and clays - turbidite flows (husdson river new york) - near continents biogenic ooze - further from continents volcanic ash pelagic clay - ex. aerosols |
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biogenic ooze |
calcareous (CaCO3) and siliceous (SiSO2) e.g. chalk largely form skeletal (tests) rep=mains and nanoplankton -coccolithophores -photic zone of tropics foraminifera diatoms radiolarians |
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algae bloom |
occur sporadically today but when Britain further south was more common Anisa satellite |
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coccolithophores |
break up to form coccoliths |
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foraminifers |
protist = single-celled animals multiple chambers 2-300 microns across sheets of calcium carbonate examine isotopes - oxygen 16 and 18 - climate change |
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diatoms |
SiSO2 2-30 microns across silica skeletons |
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radiolarians |
SiSO2 10s-100s microns across silica skeletions |
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distribution |
glacial-marine sediments - mainly surrounding Antarctica, some off wast coast Greenland land-derived sediment - mouth rivers ooze - silica dissolved sea water - facial pallets - 2-3% Antartica - high productivity = nutrient-rich water calcareous ooze - dissolved sea water - saturated upper layers (100m) - depths 100s m unsaturated of CO2 = dissolution |
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rates continental margin |
continental margin - 10-40 cm / 1000yrs |
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rate abysall plains |
calcareous ooze - 0.5-1.8m /1000 yrs siliceous ooze - 0.2-0.5cm/1000 yrs pelagic clay - 0.1-0.2/1000 yrs |
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temperature |
satellite - sea surface warmest equatorial regions - 20s-30s seasonality - less distinct than on land stabilise near land depth - changes more dramatic equatorial than high -latitude (surface temp colder) thermocline - temperature gradient |
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salinity |
average 3.5% dominated sodium chloride NaCl - also calcium potassium, sulphite ions saltiest around Mediterranean 0 red sea - can reach 3.804% low salinity - glacial melt tropic - few 100m - surface levels higher - evaporation |
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halocline |
where salinity change rapidly with depth |
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density |
depth- increases tropic higher - just under 1.024 g cm^3 high latitude - 1.0275g cm^3 function of salinity and temperature increases decrease temp increase with increase salinity |
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pycnocline |
zone in which salinity changes rapidly |
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fresh water salinity |
1.000 gm cm ^-3 |
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av.seawater salinity |
at 4 degrees - 1.025 g cm^-3 |
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surface currents |
shallow circulation - uper 100-200 m deep circulation gyres |
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gyres |
transport salt and heat spiral or vortex of wind circulate near surface water surface above - high-pressure cells Ex. North Pacific gyre - N/E trade winds moving surface water westward across northern equatorial Pacific, Coriolis effect starts to deflect water to right, plus land deflection, form western boundary effect, cold current/California current moving south = fog in area like san Francisco |
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eddies or vortex |
mixing between warm gulf stream and cool adjacent waters - can last for month then dissipate (north Atlantic) |
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current - movement |
clockwise northern hemisphere anti-clockwise southern hemisphere |
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deep water currents |
governed by gravity, driven by density differences density of water = f(temp. and salinity) cold and saline water tends to sink - drags water to replace |
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NADW |
North Atlantic deep water - Labrador sea, Greenland sea - warmed in Caribbean , flows N/E due to gulf stream, cools with altitude + salt from evaporation = denser - sinks in Greenland and Norwegian sea and offshore Canada, 15-20 million m^3 sec^-1 |
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AADW |
Sea ice around Antarctic - ice rejects solutes in water (brine expulsion) -- sinks |
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how does density increase |
ocean loses heat to the atmosphere sea ice - brine expulsion evaporation |
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effect of adding fresh water |
ice sheet north Canada - Laurentide ice sheet - melt - fresh water- density changes - creation lakes (Lake Agassiz) drain suddenly in Mackenzie river - rapid change thermohaline circulation |
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effect stop sinking of salty water in north atlantic region |
slow down/stop gulf stream p western climate = cooler |
