all Flashcards
The most abundant mineral in lithogenous sediments is __________.
quartz. Quartz is silicon dioxide, a very hard and chemically stable mineral under conditions at the surface of Earth.
From smallest to largest, what is the list of particle sizes?
clay, silt, sand, pebbles
In which environments would you expect lithogenous sediment to be the dominant sediment type?
sandy beaches, abyssal plains, at the base of a continental slope
What is calcareous ooze?
a fine-grained, deep ocean sediment containing the skeletal remains of calcite-secreting microbes
What is the calcite compensation depth, or CCD?
the ocean depth below which calcite is unstable and will dissolve quickly
What three steps are required for calcareous ooze to exist below the CCD?
deposition of calcite shells above the CCD, cover of these shells by a non-calcareous material, and movement of the sea floor over millions of years
What would happen if the depth of the CCD were above the top of the mid-ocean ridge?
Calcareous ooze would not be found below the CCD.
What can you infer about the ocean environment from a core sample composed of the following layers:
Siliceous ooze (youngest layer)
Calcareous ooze
Basalt rock (oldest layer)
The core was collected in a region of high surface productivity in water deeper than 4500 meters.
The White Cliffs of Dover are an example of what sediment type?
biogenous
Calcite dissolves more readily in seawater that is ________ in temperature and ________ in pressure.
colder; higher
Sediments derived from the remains of the hard parts of once-living organisms are called __________ sediments.
biogenous
Two common types of chemical compounds found in biogenous sediments are __________ and __________.
calcium carbonate; silica
The two major types of microscopic, planktonic organisms that produce siliceous oozes are __________ and __________.
diatoms, radiolarians
How does siliceous ooze accumulate on the seafloor if silica-based residues are dissolved slowly at all depths?
Silica tests accumulate faster than seawater can dissolve them.
Siliceous ooze is particularly abundant on the seafloor at __________ and at __________.
High-latitude environments and upwelling zones have cool and nutrient-rich waters at the surface to support silica-secreting organisms.
Which planktonic organisms thrive in cold surface waters?
siliceous organisms, radiolarians, diatoms
warm waters are to _____-based organisms as cold waters are to ______-based organisms
calcium carbonate, silica
Why do some organisms thrive in warm surface waters?
warm water is generally saturated in carbonate.
Where might one find calcareous oozes on the seafloor?
along the mid-ocean ridge, buried in siliceous ooze, buried in abyssal clay
Which of the following factors affect the distribution of biogenic oozes on the seafloor?
seafloor spreading, dissolution, water depth, biological productivity
On average, at what ocean depth does calcite readily dissolve into seawater?
4500 meters (14,764 ft)
in order of most prevalent in the ocean to least, list the three types of sediment.
calcareous ooze, abyssal clay, siliceous ooze
What do manganese nodules, metal sulfides, and evaporites all have in common?
They are all hydrogenous sediments, all precipitate from water oversaturated in their respective minerals.
The most likely place to find abundant manganese nodules is on the:
abyssal plain far from a continent
Tektites are an example of what sediment type?
cosmogenous sediment
What is the explanation for the differences in sediment abundance between the North Atlantic and North Pacific basins?
Abyssal clays are more abundant in the North Pacific than the North Atlantic because calcareous oozes dissolve before reaching the sea floor in the latter ocean basin.
Sediments found on continental margins are called:
neritic
A very important way to increase the settling rate of fine particles in the open ocean is via:
fecal pelletss
Neritic sediments are most likely to be composed of __________.
sand, silt, gravel
You take a sediment sample from the ocean floor at a depth of 5500 m. The area has low biological productivity and the CCD is at 4500 m depth. Your sample will probably consist of __________.
clay
Which resource found in ocean sediments has great economic value?
petroleum
Which of the following contains the most organic carbon on Earth?
gas hydrates
Which of the following is the major environmental concern regarding the release of methane from the sea floor to the atmosphere?
Release of large quantities of methane from the ocean causes dramatic effects on global climate.
Why do ionic compounds dissolve readily in water?
The electrostatic attraction between ions is weakened by the polarity of water.
hydrogen bonds
bonds that hold adjacent water molecules together
ions
charged atoms due to the gain or loss of one or more electrons
covalent bonds
bonds that involve the sharing of electrons between atoms
electrons
relatively charged subatomic particles that orbit an atomic nucleus
atoms
basic building blocks of all matter
The covalent bonds between hydrogen and oxygen atoms in a water molecule form as a result of the ________.
sharing of electrons between the atoms
Hydrogen bonds form between neighboring water molecules because of:
the polarity of water molecules.
Many of the unusual properties of water are attributed to the fact that water:
is a polar molecule
Water can pile up a short distance above a container’s rim due to:
high surface tension.
Atoms that have lost or gained one or more electrons are called ________.
ions
Which of the following statements comparing covalent and hydrogen bonding is correct?
Stronger covalent bonds occur within water molecules and weaker hydrogen bonds form between adjacent water molecules.
reasons why water is considered a universal solvent
Water molecules makes it much easier for ions to separate, reduce the attraction between ions of opposite charges, stick to other polar chemical compounds, and interact with other water molecules and other polar molecules.
Which of the following best defines melting point?
The temperature at which a solid changes to a liquid
describe an ion
An ion may be in the form of either a single atom or a polyatomic ion (multiple atoms), but the number of electrons and protons is unequal, and it carries a net electrical charge.
The principal reason that oil and water do not mix, even when shaken, is that oil molecules __________.
are nonpolar whereas water molecules are polar
the unusual geometry of water leads to what properties?
water has cohesion, surface tension, hydrogen bonds, polarity, the ability to dissolve almost anything
which is more dense: ice or water?
water
How does water exert a thermostatic effect on climate moderation?
Evaporation in the tropics has a cooling effect on ocean temperature.
describe how evaporation exerts a thermostatic effect on climate.
As water evaporates and it transforms from a liquid to a gaseous state, 540 cal/g of heat is absorbed by the atmosphere, thus helping to moderate air temperature.
latent heat
Latent heat is the quantity of heat gained or lost as a substance undergoes a change in state.
Which property of water causes coastal communities to have only moderate differences in daily highs and lows when compared to inland communities?
high heat capacity
heat capacity
The amount of heat energy required to raise the temperature of a substance by 1 degree Celsius.
latent heat
The energy needed to break the intermolecular bonds that hold molecules in place.
Which of the following best defines heat?
The energy transfer from one body to another due to a difference in temperature.
temperature
The direct measure of the average kinetic energy of a substance’s molecules.
true statements about water latent heat and changes in energy
Latent heat allows water to transfer energy from one place to another, in the solid state, all water molecules are connected by weak (hydrogen) bonds, When water vapor condenses and forms a liquid, it releases heat to the environment, in the vapor state, there are no weak (hydrogen) bonds between water molecule, when water evaporates, its latent heat of evaporation absorbs heat.
Vaporizing water requires how much heat energy?
input 540 calories
facts about water and ice density
As the temperature of water decreases from 4°C to 0°C, its density decreases, ice is less dense than liquid water, which is why ice floats, water at 2°C is less dense than it is at 4°C, water’s maximum density is at 4°C.
Which of the following surface seawater salinity conditions would you predict for the following location: Latitude: 60°N Longitude: 20°W
low seawater surface salinity due to precipitation
Which of the following surface seawater salinity conditions would you predict for the following location: Latitude: 30°S Longitude: 80°E
high seawater surface salinity due to precipitation
physicality of ice molecules
Water molecules in ice remain in a relatively fixed position and are not as mobile as they are in the liquid state, where there are fewer hydrogen bonds. They are bonded together.
shape of ice
rigid, forms a 3d crystalline shape, does not conform to the shape of container
Why are water molecules in a gas phase able to move rapidly and independently of each other?
There are no hydrogen bonds between water molecules in a gas phase, so each water molecule acts as an individual.
What makes water a polar molecule?
it has a positive hydrogen side and a negative oxygen side
How do hydrogen bonds define the three states of matter in water?
ice has more hydrogen bonds than any other state of water, in fact, water will be solid if there are hydrogen bonds between all molecules. In liquid water, there are some hydrogen bonds between water molecules that form and break repeatedly. There are no hydrogen bonds when water is in a gas phase.
hydrogen bonds and heat
Hydrogen bonds are responsible for the high latent heat of vaporization of liquid water to water vapor, and of the melting of ice to liquid water. Hydrogen bonds are also responsible for the high heat capacity of water.
What property of water prevents a flame from bursting the water balloon?
high heat capacity
A block of ice is in a deep freezer at –40°C. The ice is removed from the freezer and is placed in the sink. When will the ice begin to melt?
Ice begins to melt after 20 calories of heat per gram of water is applied, and when the temperature of ice reaches 0 degrees Celsius.
If you want to drink a cold glass of water, why might you want to add ice?
Any heat that is absorbed by the water will go into melting the ice, not raising the temperature of the water, so the water will stay cooler longer.
Why is the latent heat of vaporization for water so much higher than the latent heat of melting?
For melting, only some hydrogen bonds need to be broken, whereas for vaporization, all hydrogen bonds must be broken.
which is higher: the latent heat for the vaporization of water or the latent heat of melting?
latent heat of vaporization for water
The Principle of Constant Proportions states that:
the relative concentrations of the major ions in seawater does not change.
an application of the principle of constant proportions?
The concentration of a single major constituent can be measured to determine the total salinity of a water sample.
Human consumption of what component of seawater helps prevent goiter?
iodine
goiter
a swelling of the neck resulting from enlargement of the thyroid gland.
Which is the most abundant ion in seawater?
chloride
Why is chloride more abundant than sodium in seawater?
Chloride is more abundant than sodium because sources include both dissolved salts and submarine volcanic vents.
average salinity of seawater
35 ppt, or 3.5%
what are the two most common dissolved components in sewater?
sodium and chloride
If all the water in the ocean was evaporated and only the solid salt was left behind, how much salt would there be?
enough to form a layer about 500 feet thick that covers all of Earth
Which statement accurately describes the interaction between a water molecule and sodium chloride as it dissolves?
The negative oxygen end of the water molecule is attracted to the positive sodium ion.
Why is water able to dissolve salt?
Water molecules are polar and are attracted to the electrically charged ions that form salts.
Why does the water molecule have polarity?
Water is geometrically bent to give one side, or pole, a positive charge and the opposite side a negative charge.
Which attributes of the water molecule arise from the unique bend in its geometry?
The hydrogen end has a positive charge, and the oxygen end has a negative charge.
Which process in the hydrologic cycle is most effective at increasing ocean salinity on a global scale?
Evaporation
Which of the hydrologic cycle reservoirs is the smallest?
atmospheric water vapor
On an annual basis which flux between reservoirs of the hydrologic cycle is the largest?
ocean and atmosphere
On an annual basis which flux between reservoirs of the hydrologic cycle is the smallest?
Continent to ocean
processes that decrease seawater salinity
iceberg melting, sea ice melting, river runoff, precipitation
We would expect the salinity of surface waters to be higher in regions where __________.
evaporation is much greater than precipitation
The correct order of substances from most acidic to most alkaline is _______, ________, __________.
rainwater, pure water, seawater
T or F: seawater is more acidic than pure water
False
The ion in seawater that serves as a buffer is:
HCO3-.
There is a general trend of decreasing pH with increasing water depth in the ocean. What is the cause of this pattern?
Deeper, colder ocean water contains more dissolved carbon dioxide, which causes the pH to be lower.
As CO2 dissolves, it increases the amount of carbonic acid in the water, thus making it more acidic.
pH (increases/decreases) generally with ocean depth
decreases
pH of seawater
the pH of seawater is slightly basic, and higher than that of pure water. Dissolving carbon dioxide lowers the pH of sewater. The carbonate buffering system stabilizes the pH of seawater.
Calcite-secreting organisms such as __________ and __________ live in the ocean’s sunlit surface waters and form the basis of most marine food webs.
coccolithophores, foraminifers
The depth at which calcite dissolves rapidly in the ocean is called the __________.
CCD or calcite compensation depth
What happens at the CCD?
The combination of temperature and pressure result in more acidic water that dissolves calcite more rapidly.
The pH scale is a measure of the __________ ion concentration of a solution.
hydrogen
As a whole, the pH of surface waters of the ocean is slightly __________.
alkaline
average pH of the oceans
8.1 and ranges from about 8.0 to 8.3.
Carbon dioxide (CO2) combines with water (H2O) to form __________.
carbonic acid (H2CO3)
In regions with low rates of precipitation and high rates of evaporation, the halocline will __________.
decrease in salinity with depth
As the salinity of seawater increases, its:
density increases
A layer of rapidly changing salinity with depth is called a ________.
halocline
The density curve for high latitudes shows ________ density at the surface and ________ density at depth.
decreased, increased
The salinity curve for low latitudes shows ________ salinity at the surface and ________ salinity at depth.
increased, decreased
We might expect to encounter brackish ocean surface water __________.
off the coast of Washington and Oregon
Why might we expect to encounter brackish ocean surface water off the coast of Washington and Oregon?
The high volume of fresh water added by the Columbia River lowers surface salinity.
brackish
Brackish water is water that has more salt than freshwater, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root “brak”
change in state from solid to gas
sublimation
A layer in the ocean where a rapid change in ocean density occurs with a change in depth is called a:
pycnocline
A rapid change in ocean temperature with a change in depth occurs in the:
thermocline
what areas of the oceans are isopycnal and isothermal?
the high latitudes
isopycnal
points in the ocean where the water has the same density.
iso-
equal
isothermal
points in the ocean where the water has the same temperature
cline
a continuum with an infinite number of gradations from one extreme to the other. 1930s: from Greek klinein ‘to slope.’
density of seawater
an increase in salinity increases density, a decrease in temperature increases seawater density, an increase of pressure with depth has a negligible efffect on density
