Mid term

The Principle of Constant Proportions

although the concentrations may vary, the relative proportions of these salts remain very consistent worldwide

Oxygen enters seawater mainly:

as a byproduct of photosynthesis

Salt water freezes at a ___________ then fresh water.

at a lower temperature than

What are Counter-currents

currents that flow against the wind

thermostatic properties of water

The properties that act to moderate change in temperature. For instance: Water has a very high heat capacity therefore its temperature will not increase even if a large amount of heat is added

atmospheric convection

Warm moist air rising over cold dry air resulting in a convection current in the atmosphere,

Thermohaline circulation

a worldwide system of ocean currents in which warmer, fresher water moves along the surface and colder, saltier water moves deep beneath the surface

The major source of carbon dioxide in seawater is:

from the respiration of marine animals and other organisms

The most abundant gaseous components of the Earth's atmosphere are: A) carbon dioxide and oxygen. B) nitrogen and hydrogen. C) nitrogen and carbon dioxide. D) oxygen and carbon dioxide. E) nitrogen and oxygen.

nitrogen and oxygen.

Residence time is:

the average length of time an element spends in the ocean.

Ferrell cells

the middle atmospheric circulation cell in each hemisphere. air in these cells rises at 60 latitude and falls at 30 latitude

Upwelling

the movement of deep, cold, and nutrient-rich water to the surface

The upper sunlit layer of the ocean is called:

the photic zone

Radiometric dating

the process of measuring the absolute age of geologic material by measuring the concentrations of radioactive isotopes and their decay products

Hadley cells

"A large-scale atmospheric convection cell in which air rises at the equator and sinks at medium latitudes, about 30 degrees north or south"

Surface ocean circulation

- wind driven - ocean currents travel at 90 degrees to wind direction - dominated by subtropical gyres

Ocean stratification

-surface water float over cold, dense deep water -different densities mean little mixing between the two layers -nutrient rich deep waters don't mix with nutrient poor surface waters. -but light availability limits photosynthesis to only the surface waters

types of plate boundaries

1)convergent: plates collide, come together: lithosphere destroyed 2)divergent:plates seperate: lithosphere created 3)transform: plates slide hoizontally past each other: lithosphere is neither created nor destroyed

haloclines

A zone in which the ocean's salinity increases rapidly with increasing depth

What is the approximate mixing time of the world ocean? A) About 1,600 years. B) About 100,000 years. C) About 100,000,000 years. D) About 1 billion years. E) It has never been fully mixed.

About 1,600 years.

Active vs. passive margins

Active: narrow shelf, tectonically active Passive: broad shelf, tectonically inactive

Which of the following statements best describes the conservative constituents of seawater?

Conservative constituents, which include salinity, change very slowly.

driving forces of plate tectonics

Convection Heat rises from the core and that causes the plates to shift and move about

The Earth's rotation influences currents by a force (or acceleration, to be correct) known as:

Coriolis effect.

what are Undercurrents and counter- currents

Countercurrents: A current flowing in an opposite direction to another. Undercurrents: A current of water below the surface, moving in a different direction from any surface current

pycnoclines

Depth zone within which seawater density changes.

What is a Gyre

Large scale circular system of currents caused by interacting forces (wind, gravity, Coriolis force)

Major ocean currents

North Pacific Drift, Kuroshio Current, Oyashio Current, Humboldt Current, West Wind Drift, Bengula Current, Gulf Stream, Labrador Current, North Atlantic Drift

Active vs. passive margins

Passive Continental Margin: Oceanic crust and continental crust part of same tectonic plate (no volcanoes or earthquakes) Active margins: Three possible types of Active Margins, all at convergent plate boundaries o Ocean-Ocean Convergence (older crust is subducted - new crust is hot and buoyant, the older is more dense). Example: Japan o Ocean-Continent Convergence (oceanic crust is subducted). Example: Andes Mountains o Continent-Continent Convergence (neither crust is subducted, they just collide - mountains go up). Example: Himalayan Mountains

isostasy

The balancing of the downward force of the crust and the upward force of the mantle.

The Coriolis Effect

The way in which the rotation of the earth bends the path of winds, sea currents, and objects that fly through different latitudes

climate conveyor

Thermohaline circulation

A system of four currents completing a flow circuit around the periphery of an ocean basin is collectively called:

gyre

geostrophic gyres

gyres in balance between the pressure gradient and the Coriolis effect

The ocean is a "steady-state" system in regard to salinity which means that salinity is: A) increasing due to evaporation as the Earth warms up. B) decreasing due to several years of excessive rainfall. C) increasing due to pollution. D) in equilibrium, with dissolved components entering equal to dissolved components leaving.

in equilibrium, with dissolved components entering equal to dissolved components leaving.

Heat capacity of water

is 3 times that of land. Sunlight penetrates water. Constant mixing, due to waves. Maritime locations generally have longer seasonal lag.

Once an element or dissolved substance reaches the ocean

it may stay or be removed depending on the individual chemistry of the element

Thermoclines

narrow layers of fast temperature change that separate a warm upper layer of water and cold deeper waters

If you were standing on top of a high mid-Pacific island at 15º north latitude, from which direction would you expect the wind to come? (Hint: don't forget to consider the Coriolis effect!)

northeast

Ekman transport

results from Coriolis effect--surface ocean water moves into a spiral through the surface layers resulting in a net transpot of water to the right of the wind in the northern hemisphere, and to the left of the wind in the southern hemisphere

Sediment accumulation

sediment protected from erosion and accumulates layer by layer

Other than the hydrogen and oxygen atoms themselves, the two most abundant elements (ions) dissolved in seawater are:

sodium and chloride.

The property of water that accounts for the ability of liquid water to absorb heat and change only very little in temperature is called:

specific heat or heat capacity.

Magnetic striping

the stripes on the rocks on the ocean floor hold a record of reversals in Earth's magnetic field. the rocks contain iron. rock began as molten material that cooled and hardened, as rock cooled the iron bits inside lined up in the direction of the Earth's magnetic poles. This locked the iron bits in place giving the rocks a permanent "magnetic memory". Scientists found that stripes of rock that formed when earth's magnetic field pointed north alternate with the stripes of rock that formed when the magnetic field pointed south.

The most pronounced thermoclines exist in: A) the temperate zones B) the polar regions C) the tropics D) anywhere - it depends on salinity E) anywhere - it depends on water clarity

the temperate zones

CFCs (chlorinated fluorocarbons) are used to trace the movement of ocean currents because:

they readily dissolve in ocean water, are easily transported by ocean currents, are long-lived, and can be detected in very small quantities.

The Coriolis effect causes objects moving in the northern hemisphere to veer off course:

to the right, or clockwise when viewed from above

The dependable surface winds of the Earth centered at about 15º north and south latitudes are called:

trade winds

Polar cells

where polar air sinks and flows away from the poles downward meeting the ferrel cells at 60 degrees latitude