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