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145 terms

Oceanography Final

How many degrees longitude is one hour of time?
15 degrees
What three inventions were developed by the chinese to facilitate thier ocean voyages?
Compass, central rudder system, and watertight compartments
Where was the first zero longitiude?
Who is responsible for the first measurement of the circumference of the Earth?
Eratosthenes of Cyrene
What prevented explorers like Christopher Columbus from finding precise longitude?
The lack of a durable and precise clock. (clocks were run by pendulums which are not efficient with the rocking of the sea)
True or False: Longitudinal lines run parallel to the equator
True or False: The Polynesians used a system of shells and bamboo to represent island positions for navigation
A ____ is a very large column of superheated mantle that originates at the boundary of hte core and mantle
A plume
If P and S waves travel at the same speed, what can be inferred of the Earth's core?
The interior is homogenous. (one of the waves can travel through liquid one can not)
What is paleomagnetic data used for?
measure spreading rates, reconstruct positions on Earth, and to calibrate the geological time scale
Primary waves travel ____ as fast as secondary waves
Primary waves travel twice as fast as secondary waves
What allowed scientists to confirm thier belief that the Earth's interior is layered?
A measurement of a large earthquake that occured in Alaska, a system of 800 siesmic states placed worldwide, and the correlation between intensity, frequency and characteristics of siesmic waves
What is considered to be the densest type of CRUST?
Oceanic crust
True or False: Hotspots always occur at plate boundaries
False: Hot spots are surface expressions of mantle plumes and rises from a stationary source of heat.
True or False: Transform plate boundaries are not involved in the creation or destruction of crust, rather they just move past one another
How long is it estimated to take the ocean's volume of water to circulate through the ocean's crust and spreading centers?
10 million years (its is estimated that a volume of water equal to the volume of hte world's ocean will circulate through the spreading ceners and crust every 10 million years)
Sattelites use _____ to measure the depths of the ocean?
variations in elevation of surface water
If oceanic ridges in the Pacific are more active, then it is expected that the ridges are:
Wide- the widest ridges are considered to be the most active. Fast spreading centers do not build up because of the time it takes the diverging centers to create new crust. The Pacific has mroe active spreading centers.
What is the flattness of abyssal plains associated with?
Large amounts of sediments- msot of this sediment is terrestrial in origin
What type of bathymetric feature was heavily influenced by wave action in some point in its history?
Guyots- were seamounts at some point in thier history
True or False: The fundamental success of ocean depth measurements taken by satellites is based on the variation of gravitational pull associated with bathymetric features
True- Satellites measure the distance between the oceans surface and the satellite. Gravity creates mounds of water slightly higher when an underground feature is present and the heigh depends on hte "height" underwater
True or False: The sinking of the RMS titanic fueled research that would influence the science of bathymetry
True- Echo indicated the presence of an underwater object(iceberg) and could project an image based on echo returns
If there is an abundant amount of forminefra shells found in a sediment it would be characterized as:
A calcareous ooze- ooze is created when 30% is of biological origin (calcareous oozes form from forminefra and cocolithophores)
What is the main sourse of terrigenous sediment?
Rivers- Terrigenous sediments are derived from land. Erosion of sediments is carried by rivers and placed in the ocean from runoff
Hydrogenous (Authigenic) sediments:
Precipitate directly from seawater
What valuable commadity has yet to be commercially mined from ocean sediments?
Manganese nodules- due to price and low market value
What are turbidites?
They are composed of distinct layersthat represent different turbidity current events, graded layers of terrenous sand mixed with finer pelagic sediments, and are propelled into position based on gravity not water currents
True or False: Clays can stay suspended in a water column for decades without settling out due to their small size
True or False: Neritic sediments are mainly composed of biogenous sediments due to close proximity to continental shelves
False- Neritic sediments are mainly composed of terrigenous sediments because of thier close proximity to continental shelves
As pure water approaches its freezing point, the density decreases. Why does this happen?
The hydrogen bonds become more ridgid allowing it to expand slightly- the bond angles widen slighty allowing a lattice structure to form (slightly larger liquid water form)
The pynocline isolates the majority of the oceans from:
Wind driven circulations, light, heating and cooling brought on by solar fluctuations (pynocline protects deep water from surface circulation
What is the name of the zone that decreases temperature with depth?
Thermocline- temperature decreases rapidly. This is a major factor in the change in density and subsequently the pynocline
What important characteristic of water is the blue color attributed to?
the hydrogen bonds- the ibrations from hydrogen bonds allow some red light to be absorbed, reflecting blue to our eyes
What is the typical depth of light penetration?
100 meters
What allows water to be a polar molecule?
The angular shape of the model
What is true of heat capacity?
it is the measure of heat required to raise 1 gram 1 degree Celsius
What can effect waters density?
Pressure, temperature, and salinity
True or False: The annual freezing and thawing is a major factor in temperature regulation on Earth
True- the melting and freezing of water requires and releases heat energy
True or False: The amount of heat energy transferred in the ocean is significantly higher than that in the atmosphere
False- There is more heat being circulated in the atmosphere than in the ocean. Water vapor is able to transfer more heat due to high latent heat of vaporization
The amount of ____ increases with depth which is a factor in the carbon compensation depth
Carbon dioxide levels increase as depth increases (contrastingly oxygen level decrease as depth decreases)
What enhances the ocean's buffering capacity?
The amount of dissolved inorganic carbon present- This makes the ocean less prone to large pH changes
What is solute?
A substance that dissolves in another substance- usually a dissolved gas or solid and usually less than the amount of solvent
What are the factors of salinity?
Evaporation, Precipitation, and freshwater runoff from continents
What is source of high carbon dioxide at middle depths in the ocean?
The decay of the remains of organisms- CO2 is higher at middle depths then at the surface (respiration from animals and the decay of the remains of organisms are the large contributers to high levels of CO2
What is considered a trace element in the ocean?
Nitrogen- despite of its abundance in atmosphere it is a trace element in ocean (trace elements even though in small quantities are often crucial for life)
True or False: at any given pH carbon dioxide and the ions it disassociates in water are in equilibrium
True- all equal unless pH is altered
True or False: Carbon dioxide is abundant at the surface due to photosynthesis of plants
False- oxygen is abundant at the surface due to photosynthesis of plants
True or False: Sodium and Chloride are considered to be nonconservitive constituents with long residence times in the ocean
False- they are considered to be conservitive constituents with long residences times in the ocean (nonconservitive constituents have short residence times)
Extratropical cyclones form between which two types of atmospheric cells?
A polar and a Ferrel cell
Horse lattitudes at sea correspond to ___ on land?
Great deserts- Horse lattitudes are where Ferrel cells and Hadley cells intersect. Air falls to the surface and creates areas of compressional heating
If a ship is trying to sail from Eastern United States to Europe, what route would be the most efficient to take?
A northern route to take advantage of the Westerlies
What is a storm surge?
An enormous wave generated by the low pressure area in a storm
What determines the availability of energy in a tropical cyclone?
The storm must stay over warm water- also needs a ready source of hot and humid air
What is not a factor of the amount of light penetrating the ocean?
The amount of light absorbed by clouds- THE FACTORS ARE: The surface turbulence of the ocean, the angle at which light approaches the ocean, and the presence of ice or foam on the ocean surface
What is the residence time of water vapor in the lower atmosphere?
10 days
What occurs at the boundaries of circulation cells?
air moves vertically where boundaries meet- the surface winds become weak and erratic
Why are there multiple atmospheric cells instead of one big one?
There are intermittant precipitation events that break up the air into circulation cells
What direction would a gyre in the Sourthern Hemisphere flow towards?
Counterclockwise- It deflects to the left (Corriolis Effect)
What does NOT effect surface currents?
Density- ( WIND starts the flow of surface currents and GRAVITY pulls the water dowslope where the CORRIOLIS FORCE deflects the approaching water)
What are characteristics of EL NINO southern oscillation?
Equatorial currents stop, trade winds across the Pacific weaken or reverse directions, and high pressure areas shift to the Western Pacific
What is a characteristic of Antarctic Bottom Water?
Extreme density and moves very slowly
What is the name for slow deep currents in the pynocline?
Thermohaline currents- depend on density differences which stem from temperature salinity variations
What is used to visualize ocean layering?
A temperature-salinity diagram- layers are dictated by density. (water masses with same density but different temperature can combine to form new water masses with greater density)
What maintains the permanent thermocline at all mid and low lattitudes?
Continental upwelling- the thermohaline flow of water rises to the surface in temperate and tropical zones and sinks back down at the poles. This diffuse upwelling maintains the thermoclines
True or False: The Corriolis Effect and gravity maintains the hill of water present at the center of the oceanic gyres
False- It is maintained by wind energy
True or False: The horizontal movement of water by wind can lead to vertical movement in surface water
True- this is called wind-induced vertical movement
True or False: Upwelling can increase biological activity, but is unable to influence weather conditions
False- upwelling CAN influence weather (for example- bringing cold water to the surface can chill the air above it)
How fast do wave trains travel in relation to individual waves in that train?
Half the speed
What causes ocean waves to form?
Energy from the disturbing force- the force can vary but is mostly wind
What is characteristic of a tsunami?
Long wavelegths- they are shallow water waves and have long wavelengths and can be initiated by vertical movements along faults
What is a fetch?
An uniterupted distance over which wind blows- fetch is one factor in the development of wind waves (wind speed, and duration and direction over the fetch are the factors)
What is a rogue wave?
Constructive inference of many wavelengths, a wavce much larger then the theoretical maximum, and a freak unpredictable wave
What kind of wave occurs at the boundary between two fluid media?
orbital waves- they have medium water flowing in closed circles as the wave passes. Circular waves transmit wave energy across the surface of the ocean
When does a wave begin to interact with its bottom?
When the bottom is shallower then half the wavelength- a wave in unable to "feel" the bottom if the depth is greater then half the wavelength
True or False: Another name for a storm surge is a storm seiche due to the amount of water pushed ashore
False- some call them storm tides
True or False: The circular motion of water particles at the surface continues underwater at orbits of decreasing diameter
True- The orbits rapidly get smaller with depth
Barrier Islands are:
form when sediments accumulate on submerged shelves- they are narrow and exposed sandbars, and parallel to the shore but separate to the land
What are the MOST COMMON large scale features on a depositional coast?
Sand spits- form where longshore currents due to headlands
What is a fjord?
A deep narrow bay- fjords often begin formation via tectonic plates and are later shaped by glaciers
Why are erosional coasts prone to become smoothe straight shorelines?
Wave energy focuses on headlands, sediments begin to collect at beaches, and wave refraction
If a coastline if covered by sea cliffs what type of beach is it most liekly to be?
An erosional beach- sea caves occur where erosion takes place at weakened areas of sea cliffs. the caves are mostly only available at low tides
An erosional coast that has little tidal variation:
Can erode quickly because wave action is centralized-
What is the term that describes global, long-term change in sea level?
Eustatic change- there are three factors heavily influencing eustatic change (global glaciations, the amount of seafloor spreading, and temperature variation)
What creates a morraine?
Glaciers and glacier retreat
A salmon migrates from the ocean to a river to spawn. What is the fresh water environment for the salmon?
Hypertonic- the water would be moving from the outside of the fish into its cells
What is a heterotroph?
An organism that eats other organisms- must consume food to obtain energy
What is rarely a limiting factor for marine organisms?
Hydrostatic pressure- inside pressure=outside pressure (three factors for marine organism are salinity, pH and nitrogen levels)
What is the immediate organic material produced from inorganic material?
Glucose- dissolved carbon dioxide provides the carbon dioxide needed for glucose (primary productivity)
What kind of movement of particles is able to move against the normal concentration gradient?
Active transport- it is able to reverse passive diffusion and requires energy to perform
What open water is near shore and over the continental shelf?
Neritic zone- subdivision of the pelagic zone (those in open water)
What organism usually fixes nitrogen into usable chemical forms?
cyanobacteria- bacteria and cyanobacteria usually fix nitrogen
What traps light in primary producers?
clorophyll- energy gets transformed into chemical energy by chlorophyll in primary producers where they are able to make sugars
What is needed for living organisms to function?
Engery- energy can not be created, only transformed
What community has the highest level of net primary productivity?
Coral Reefs
The highly biological productive ocean surface appears chalky; what planton is likely successful here?
Coccolithophores- create chalky ooze
What allows diatoms to expand in size during reproduction?
auxospores- naked diatom cell without valves. in favorable reproduction conditions it will reproduce and in infavorable conditions it will remain dormant.
What is a frustule?
the rigid cell wall of a diatom- mostly made of silica
what is created due to the decomposition of falling biological debris and zooplankton activity?
the oxygen minimum zone- below the surface zone, and gets depleated by animals but not replaced by photosynthesis
What is plankton?
A drifting organism
What is usually responsible for a harmful algal bloom?
dinoflagellates- high phytoplankton attract dinoflagellates
What photosynthetic organism is found in the tissues of coral?
Where is phytoplankton most productive?
Temperate lattitudes- due to plenty of sunlight and moderate nutrient supply
Why are phytoplankton critical for marine life?
they are able to bind billions of carbon into carbohydrates, they are a large contribution to marine food webs, and they generate massive amounts of atmospheric oxygen
What adaption have only toothed whales made for prey detection?
echolocation- the equivalent of biological sonar
What class is comprised of nautilises octopus and squid?
What do the simplest vertebrates lack?
What is considered the most advanced animal phyla?
Chordata- (have a notochord, hallow dorsal nervous system, and gill slits at some point)
What is considered the most primitive true animal?
Porifera (sponges)
What is the most effective anti drag body plan?
How is drag determined?
frontal area, body contour, and surface texture
What makes up the greatest biomass of any species on Earth?
Krill- is a planktonic anthropod
What phylum contains sea jellies?
Cnidaria- carnivorous animals with stinging cells
What unique feature do all echinoderms have?
A water vascular system
Which marine reptiles make long migrations to lay eggs on the very same beach they hatched from?
Sea turtles
What community has the highest biomass per unit of area?
What describes a fish species with narrow tolerance for temperature changes?
Stenothermal- (steno=narrow, and eury= broad)
What determines the number and composition of populations in a community?
light, food, and space
What do most deep water consumers depend on for survival?
The productivity of the water column above
What is a climax community?
A stable long established community
What is a community?
A group of interacting organisms of different species
What is a hardship for small organisms that are associated with living on a sandy beach?
They have a hard time finding a firm footing when burrowing, sand has sharp jagged edges, and capillary forces pin organisms down within the sand
What is a niche?
An organisms occupation within a community
What process re-establishes climax communities after a major disruption in thier environment?
Succession- the relocation of a few highly tolarant species into the area
Which distribution is the rarest found in communities?
Uniform distribution
How is freshwater obtained as a marine resource?
Desalination- seperation of pure water from sea water
How much of the fish stocks is overfished?
What is bycatch?
Organisms unintentionally killed during the harvesting of a different desirable species
What is the fastest-growing energy alternative to oil?
Wind power- wind is steady over the ocean
What is the petroleum found in marine sediments most likely to be formed from?
Bacteria and planktonic organisms
What type of net has been particularly destructive in the mistargeting of species?
Drift nets
What was first created in an effort to claim the continental shelf as belonging to the nation it was attatched to?
The law of the Seas
When a resource is present in a fixed amount, it is said to be:
A non-renuable resource
Why is methane hydrate not harvested for energy use?
It is costly to mine an harvest, the methane disapears as its brought to the surface, it is hard to mine due to methane's combustibility
Why is the extraction of wind so effective over or near the ocean?
The winds tend to be steady
Although this is a comment element in the atmosphere is not considered to be a greenhouse gas:
What could happen if global warming were to continue?
Rise in ocean temperature, decrease in dissolved gasses, and changes in global winds and rainfall
What determines an organisms response to a particular pollutant in the environment?
The quantity of the pollutant, the persistance of the pollutant, and the toxicity of the pollutant
What happens to the volatile componants after any oil spill?
They evaporate into the air
What happens when corals exceed their normal temperatures for too long a period of time?
They expel thier zooanthellae- coral bleaching is what it is called
What is a biodegradable pollutant?
One that can be broken down into simpler compounds
What is favorable about global warming and perhaps one advantage?
It will open the Northwest passage
What is the most visible manifestation of eutrophication?
Plankton bloom- usually dominated by a single species
Where does the largest addition of oil to the ocean come from?
Runoff from land and city streets
Which habitat is most impacted by pollutants?
Estuaries- most pollutants get washed down by rivers straight into the estuary
What is hypoxia?
Defficiency of oxygen