Intro to Oceanography Exam 1

what is the difference between a short and long residence time?

- longer residence time = unreactive ("conservative"), higher concentration in seawater - short residence time = insoluble or reactive, smaller concentration in seawater - steady state = ocean salinity nearly constant through time

what is the normal measurement of density in fresh water and sea water in sigma t?

0 = freshwater 28 = seawater

deep ocean temperatures are usually between what?

0 to 4 degrees centigrade

what are the 2 main sources of dissolved material (salt) in the ocean?

1) chemical weathering on land 2) hydrothermal weathering on the ocean floor

what are the 2 reasons why ocean waters are colder with increasing depth?

1) cold waters are denser than warm waters and, hence, tend to sink 2) deep waters are generated at high latitudes, where surface waters are cold, and then sink and flow beneath warm equatorial surface waters

what 4 things are ocean surface salinity controlled by?

1) evaporation - increases salinity 2) freshwater runoff - reduces salinity 3) atmospheric transfer of water vapor (freshwater) - across Central America 4) Sea-ice formation - increases salinity

where are the lowest areas of salinity?

1) high latitudes 2) North Pacific and Southern oceans

seawater temperature variation is controlled by what 3 things?

1) latitude (cold waters in Arctic and Southern oceans) 2) global deep ocean circulation 3) inflow of warm Mediterranean Intermediate Water (MIW)

what are the 3 ocean layers?

1) mixed surface layer 2) pycnocline / thermocline 3) deep ocean

what are 2 sources of salt added to oceans?

1) river input (primarily) 2) circulation through mid-ocean ridges

what are the 3 ways salinity changes?

1) salinity changes by adding or removing water 2) salinity decreases by precipitation (rain/snow), river runoff, melting snow 3) salinity increases by evaporation and formation of sea ice

what are 4 "sinks" of the ocean? (salt removed)

1) salt spray 2) recycling through mid-ocean ridges 3) biogenic sediments 4) evaporite formation and burial

density of seawater is controlled by what 3 things?

1) temperature 2) salinity 3) pressure - density increases with decreasing temperature, increasing salinity, and increasing pressure

what is the range of percent of salinity in the ocean?

32% - 37%

what is typical seawater salinity?

35 ppt (parts per thousand)

what percentage sodium chloride is sea water?

80%

who gave the first calculation of residence time? what is it?

John Joly, 80-100 million years old

where are the areas of highest salinity located?

North Atlantic (main source of ocean deep waters)

where are the areas of lowest salinity located?

North Pacific (strong freshwater input to surface here)

what happens to density as you go down the ocean?

always increases

what is the reservoir theory?

analyzes the movement of material between different reservoirs in the Earth system. It is a powerful tool for evaluating changes in ocean chemistry

major transfers of energy to atmosphere occur when?

as water vapor is converted to liquid water during the precipitation process

which ocean's surface waters have the most salinity?

atlantic

what is residence time?

average length of time a substance remains dissolved in seawater

what is the word to describe less than sea water salinity? < 33 ppt

brackish (hyposaline), usually results from mixing with freshwater, as in coastal areas

what is the dominant dissolved material in salt water?

chloride (anion = negative charge)

what is the relationship between temperature of seawater and density?

cold water = high density warm water = low density

how is density measured?

conductivity

what is the ability conduct electricity called?

conductivity

what does a CTD instrument meausure?

conductivity-temperature-depth

there is _____________ change in density as you go down the coean

continuous

what is the layer called of the ocean between 1000 meters and the bottom?

deep water - uniform variation

what controls ocean circulation?

density

what are the 3 major properties of seawater?

density, temperature, and salinity

evaporation tends to be stronger at what side of ocean basins?

east side - where cold equatorward-flowing currents are located

climate belts are due to what?

global-scale atmospheric circulation

what is a rapid change of salinity with depth called?

halocline

what are the 3 different names for the different types of gradients?

halocline = salt gradient thermocline = temperature gradient pycnocline = density gradient

density flows can carry a lot of fine material in suspension, producing a deposit after the material rains out, what is this deposit called?

hemipelagic deposit

the greater the amount of salt, the ____________ the conductivty

higher (salt water = conductive)

how does conductivity show amounts of salinity?

higher concentrations of dissolved salts result in higher electrical conductivity

what is the word to describe greater than sea water salinity? > 38 ppt

hypersaline, usually results from strong evaporation

what layer of the ocean has the most rapid change?

intermediate layer

what is the layer called of the ocean between 200 meters and 1000 meters water depth?

intermediate layer - very rapid changes in properties, big changes in salinity, temperature, and density

what is a line of equal density on a TSD diagram called?

isopycnal

what is a line of equal temperature called on a graph?

isotherm

temperatures are lower in the south polar region than the north polar region, why?

landmass - temperature extremes are greater over land areas (Antarctica) than over oceans, such as the Arctic Ocean at the North Pole

what might be a reason why a number of ships and airplanes get lost in the Bermuda Triangle?

methane "mega bursts", where giant bubbles of methane are released from the seafloor and suck down unfortunate vessels

where on earth are temperatures highest?

near the equator

fresh water is electrically ________________

neutral (nonconductive)

salinity is the strongest influence on density in _______________ oceans

polar - minimal vertical temperature variations in polar oceans make salinity the most important control on density there

climate on earth is closely related to what 2 things?

precipitation and salinity levels

what is the total amount of solid material dissolved in water?

salinity (g/1000g)

at low temperatures, the influence of ________________ is greater than the influence of ________________ in controlling density

salinity; temperature

temperature is more likely to change in shallow or deep water mass?

shallow

what is the second largest dissolved material in salt water?

sodium (cation = positive charge)

the hydrologic cycle is driven by what kind of energy?

solar

what is ultimately responsible for both atmospheric and oceanic circulation?

solar energy

what is the layer called of the ocean surface down to 200 meters water depth?

surface layer (wind mixed layer) - wind causes the waters to mix together, relatively uniform conditions

latitude controls what?

temperature

what does a TSD diagram show?

temperature-salinity-density shows combined influences of temperature and salinity on seawater density

what does stratification describe?

the layering of oceanic water masses, which are predominantly thin and laterally extensive (very thin pancakes)

the ocean is perfectly "density stratified", what does this mean?

the least dense water masses are on the surface, the densest water masses are on the bottom, and there is a density continuum from top to bottom

what is the hydrologic cycle?

the movement of water over the earth's surface

there is high salinity in what two tropics?

tropic of cancer tropic of capricorn - also the driest zones, P < E (precipitation < evaporation)

temperature is the strongest influence on density in _______________ oceans

tropical - large vertical temperature variations in tropical oceans make temperature the most important control on density

surface ocean salinity is ______________, while deeper ocean salinity is nearly the _________________

variable; same

evaporation tends to be weaker at what side of ocean basins?

west side - where warm poleward-flowing currents are located

is saline water conductive?

yes - conductivity is proportional to salinity, hence salinity can be calculated from conductivity

what is total deep water salinity variation?

~0.5 ppt (about 1/10 of surface waters)

what do oceanographers most commonly use to measure density?

σT - sigma t σT = X - 1000