Oceanography Exam 1
Describe Earth System
Geosphere, Atmosphere, Biosphere, Hydrosphere
continental rise
gently sloping area at the base of the continental slope; transition from margin to deep ocean floor (has turbidite currents)
storm surge
low pressure center of hurricane that makes a "hill" or dome of water on the sea surface that moves with storm; very destructive, causes most destruction and deaths during hurricanes
climate
long-term environmental conditions in region/entire planet
latitude & distribution of solar radiation
low latitudes: concentrated solar radiation in small area (little light reflected bc of high angle high latitudes: sam sunlight spread over larger area
oceanic heat flow
low latitudes: more heat gained than lost high latitudes: more heat lost than gained
salinity variations vs. depth & latitude
low-latitudes: salinity decreases with depth high-latitudes: salinity increases with depth
Oceanic Crust
made of basalt; higher density
Continental Crust
made of granite; lower density
carbonate buffering system
maintains ocean's pH of 8.1
formation of deep currents
occur below pycnocline and influences 90% of all ocean; caused by density differences
Transform Fault
occurs BETWEEN offset mid-ocean ridge at transform plate boundary moves in opposite directions many earthquakes
Fracture Zone
occurs BEYOND offset mid-ocean ridge not at plate boundary moves in same direction few earthquakes
sea ice
frozen seawater
Atmosphere
gas layer around Earth
why is water a good solvent?
"universal solvent" that can dissolve more compounds than any other solvent
water density as function of temperature & ice formation
-Density increases as temperature decreases -At 0 degrees, ice begins to form & density of water decreases
lithogenous distribution in pelagic environment
-deep water deposits, found in deep-ocean basins -finer-grained sediment -deposited slowly
silica biogenic sediment
-from diatoms/algae & diatomaceous Earth -from radiolarians/single-cell orgs & bacterial/plankton -Siliceous ooze
calcareous biogenic sediment
-from nannoplankton/alage & coccoliths -from foraminifera- single cell orgs -Calcareous ooze
Coriolis effect
-rotation of Earth causes moving objects to follow curved paths (N. Hemisphere → to right; S. Hemisphere → to left) -Varies based on latitude- effect is 0 at equator & greatest at poles -Depends on amount of time object in motion -Only changes direction of moving object, not speed
lithogenous distribution in neritic environment
-shallow water deposits, found in continental shelves -close to land -coarse-grained sediment -deposited quickly
Evidence of plate tectonics
1. magnetic evidence of seafloor spreading 2. age of ocean crust 3. heat flow 4. distribution of earthquakes 5. satellite measurements
Atlantic Ocean
2nd largest ocean
El Nino-Southern Oscillation (ENSO)
A reversal of wind and water currents in the South Pacific Occurs every 2-10 years, irregular, lasts 12-18 months
Hydrosphere
All the water on earth (solid, liquid & gas)
CCD
Calcite Compensation Depth Depth where CaCO3 dissolves quickly Ocean pressure increases and properties of water change (lower temp, higher pressure, high CO2, more acidic)
Earth's internal chemical structure
Crust - low density Mantle Core- high density
western boundary current
Currents that are big, narrow, warm, deep and fast flowing on the west side of ocean basins and carry water from the tropics poleward
Earth's internal physical structure
Lithosphere, Asthenosphere, Mesosphere, Outer Core, Inner Core
active continental margin
a continental margin that coincides with a plate boundary (convergent or transform); high tectonic activity
Earth's internal structure
chemical composition & physical properties
pycnocline
a layer of water in which there is a rapid change of density with depth
abyssal plains
a smooth, nearly flat region of the deep ocean floor; deepest parts of ocean; from by falling sediment over time; feature of deep-ocean basin
thermocline
abrupt change of temperature with depth
Features of deep-ocean basin
abyssal plains, volcanic arcs, ocean trenches
Formation of solar system- Neublar Hypothesis
all bodies in the soar system formed from nebula, cloud of gas & space dust
conveyer-belt circulation
an integrated model combining deep thermohaline circulation and surface currents; changes in global deep water circulation pattern that can dramatically affect climate
mid-ocean ridge
an underwater moutain chain where new ocean floor is formed
pH variation with depth
at the surface, pH is 8.1, as you get slightly deeper pH decreases in layer because of marine respiration, but then pH gradually increases with depth
why is water a dipolar molecule?
bc it has a positive charge end and negative charge end
carbonate buffering system if ocean pH increases (more basic)
bicarbonate ion releases H+, drops pH
fronts
boundaries between air masses warm front: contact between warm air mass moving into cold air area cold front: contact between cold air mass moving into warm air area
carbonate buffering system if ocean pH decreases (more acidic)
carbonate ion combines with H+, rises pH
Steps of Wilson Cycle
continent splits apart → narrow sea forms → basin fully formed & mid-ocean ridge forms → subduction zone forms & basin gets smaller → plates come back together → ocean disappears, mountains created as continents collide
Features of continental margins
continental shelf, continental slope, continental rise & trenches
air movements and atmospheric pressure
cool, dense air sinks → higher surface pressure warm, moist air rises → lower surface pressure AIR ALWAYS FLOWS FROM HIGH TO LOW PRESSURE
continental margins with cold currents
cool, dry air
difference between covalent bond & hydrogen bond
covalent bond stronger than hydrogen bond
wind belts
created by low circulation cells closest to surface of Earth
Lithosphere
crust & upper mantle cool, rigid shell includes oceanic (high density) & continental (low density) crust
Isostatic Adjustment
crust moves vertically; less dense continental crust floats higher than dense oceanic crust
boundary current
currents associated with gyres that flow around the periphery of an ocean basin
eastern boundary current
currents that are wide, shallow, slow & small, equatorward-flowing cold drifts of water on the eastern side of ocean basin
density stratification
dense material sinks, lighter material rises in layers; Early Earth: high density stuff settles in core, less dense stuff forms spheres around core
rift valleys
depression surrounded by steep walls that goes along crest of mid-ocean ridge; feature of mid-ocean ridge
westerly wind belt
falling air in subtropics, moves along surface to high latitude
cause of high pressure zones
falling, cool air
passive continental margin
far from plate boundary; low tectonic activity
continental shelf
flat zone from shore beneath ocean surface to shelf break
Formation of Earth's atmosphere
formed by density stratification; 1st atmosphere: blown out to space; 2nd atmosphere: water vapor, carbon dioxide, hydrogen, etc
water's effect on global temperature
heat energy exchanged/redistributed in water cycle: Energy from sun stored in ocean → evaporation takes heat from ocean to atmosphere → water vapor condenses in cooler, higher air to form clouds/rain → release of latent heat of condensation
heat capacity
heat needed to raise the temp. of any substance by 1 degree
polar easterly wind belt
high pressure air moves away from poles
Asthenosphere
hot, soft layer of the mantle on which the lithosphere floats flows with high viscosity & helps lithospheric plates move
icebergs
ice that formed on land and broke off from glaciers
land breeze
land to ocean: when land cools → causes dense air to sink & flow toward warm ocean; during night
thermal properties of water
large capacity to store heat; changes state because of heat absorbed from environment
gyre
large horizontal circular moving loop of water
Pacific Ocean
largest and deepest ocean; 1/2 of all oceans
halocline
layer of water that separates ocean layers with different salinity
classification of marine sediments
lithogenous (land), biogenous (organisms), hydrogenous (water), cosmogenous (outer space)
Plate Tectonics
lithosphere crust plates moving horizontally; because of plates moving, continents move too (continental drift)
Biosphere
living organisms on Earth; connected to atmosphere
Density
mass per unit of volume; high density = heavy for size
thermohaline circulation
movement of ocean water caused by density difference brought about by variations in temperature and salinity. As ocean water freezes at the poles it concentrates salt, and the colder, denser water sinks aka deep currents
wind
moving air from high to low pressure
ocean current
moving masses of water; surface currents: wind driven, horizontal current; deep currents: density driven, vertical current
principle of constant proportions
ocean is well mixed, components are the same in all parts of the ocean but salinity varies in different parts
sea breeze
ocean to land: when air warmed by land rises → gets replaced by cool ocean air; during day
processes that decrease seawater salinity
precipitation, runoff, icebergs melting (adds water)
monsoon circulation
seasonal reversal of pressure and wind in a large continental region. Strongest in Asia, where winter winds from the Asian interior produce dry winters and summer winds blowing inland from the Indian and Pacific Oceans produce wet summers
Wilson Cycle
opening and closing/life of ocean basins; uses plate tectonics to show formation, growth and destruction of basins
Formation of Earth's oceans
outgassed water vapor released, then falls as rain oceans made by dissolved rock elements: salinity develops, rain dissolves rocks and dissolved compounds accumulate in ocean basin
resources provided by marine sediment
petroleum, gas hydrates, sand & gravel, evaporative salts, phosphorite
divergent plate boundary
plates move apart; sea floor created; ocean-ocean crust or continental-continental; forms mid-ocean ridge & volcanoes
convergent plate boundary
plates move towards each other; old sea floor destroyed by subduction; oceanic & continental crust; forms trench & volcanic arch
transform plate boundary
plates slide past each other; oceanic & continental; creates transform fault
hydrogenous sediment
precipitation of dissolved materials from seawater
Features of Mid-ocean Ridge
rift valleys, seamounts, hydrothermal vents, pillow lava
convection cell
rising and sinking air
cause of low pressure zones
rising, warm air
lithogenous sediment cycle
rock weathers → erodes & moves downhill to sea → on seafloor travels with plate to be uplifted or subducted → material made into mountains again
Geosphere
rocks & minerals part of Earth
pillow lava
rocks formed when hot basaltic lava cools fast; feature of mid-ocean ridge
why does salinity vary in different parts of ocean?
salinity affected by all processes that add or remove water (precipitation, runoff, melting ice, evaporation, etc.)
hydrothermal vents
sea floor hot springs created when cold seawater seeps down along cracks and fractures in the ocean crust and approaches an underground magma chamber; feature of mid-ocean ridge
processes that increase seawater salinity
sea ice forming, evaporation (removes water)
tropical cyclone
severe storm with large rotating mass of low pressure, strong wind & rain; Origin: release of latent heat of condensation warms atmosphere, powers storm → air rises & pressure decreases → more warm & moist surface air drawn into storm → air cools and forms rain
continental margins
shallow water areas close to shore
weather
short-term, environmental conditions on small area
Arctic Ocean
smallest and shallowest ocean
continental slope
steep slope where deep ocean basins begin (has submarine canyons_
trade wind belts
strong winds from east
storm
strong winds, precipitation, thunder & lightening caused by seasonal change in pressure systems over continents; air masses from high and low latitudes, meets at midlatitudes causing storm
Ekman spiral
surface winds drive surface currents, and each layer of water drags the layer below, but the Coriolis Force changes each layer's direction slightly to make a spiral effect
residence time
the average length of time that a substance resides in the ocean; higher RT = higher concentrations
what causes Earth's seasons?
the tilt of the Earth's axis
Ekman transport
the water movement 90 degrees from the wind direction
western intensification of subtropical gyres
top of hill forming subtropical convergence in gyre is closer to western boundary of the gyre than the center; western boundary currents of subtropical gyre is faster, deeper, narrower than eastern boundary current
salinity
total amount of material dissolved in sea water
turbidy current
underwater avalanches of sediment, water & rock caused by earthquakes, sediment banks collapsing & sediment from flood water
seamounts
underwater volcanoes; feature of mid-ocean ridge
currents & climate
warm surface currents: warm the air and carry water vapor over continents → rain
continental margins with warm currents
warm, humid climate
density variations in the atmosphere
warm, moist air rises → less dense cool, dry air sinks → more dense
geostrophic currents
water flows down hill → Coriolis effect opposes gravity and deflects water to the right → effect of gravity and Coriolis balances
downwelling
water moves from surface to deeper; carries O2 down
upwelling
water moves vertically from deeper part of ocean to surface; cold, rich in nutrients
plate boundary
where plates interact with each other associated with tectonic activity