Flashcards
Oceanography I
Flashcards do conjunto (97)
- 1Are new starts still being formed today?Yes
- 2How are stars formed?They started forming after the intense heat of the Big Bang cooled and cold matter began condensing into large-mass objects due to gravitational attraction. When an object's mass becomes very large, the gravitational compression within the center of those objects makes the interior hot enough to ignite thermonuclear fusion
- 3Where did all of earths heavy elements come from (carbon, nitrogen, copper, etc.)?They were created inside of stars or when stars exploded
- 4How was our moon formed?A mars size object hit the earth, and ejected material coalesced to form the moon
- 5According to our current scientific understanding, where did most of the water come from that fills the earths oceans?Asteroids
- 6If you were on a boat at 10N and 160W, which ocean would you be in?Pacific
- 7How quickly did life appear on earth after it cooled and the oceans filled?Around 500 million years (quickly)
- 8Where did the oxygen in the atmosphere come from?photosynthesis
- 9When did oxygen finally appear in the earth's atmosphere and in the ocean?About 1 billion years after the earth formed
- 10When did life on land begin?About 500 million years ago
- 11How old is the shale rock found around Ithaca NY?About 350 million years old
- 12What led Alfred Wegner to confirm that the continents had drifted over geologic time?Fossil and mineral belts on separate modern day continents aligned neatly when the continents were artificially moved into a single super-continent
- 13Does the rigid outer crust of the earth float like a cork on top of the mantle material below, or is the earth's crust more like a rigid outer shell of an egg that does not float?The crust floats on the underlying mantle material
- 14What kind of tectonic processes take place in the deep sea trenches?This is where ocean crust continuously sinks back into the mantle
- 15Why is the symmetric banding of magnetic anomalies along mid-ocean ridges considered to be strong evidence to seafloor spreading?Because magnetic anomalies are a proxy for the age of the rock, and when dated, they show the crust getting symmetrically older as you move away on either side of the mid-ocean ridge
- 16What is the driving force for tectonic plate motion?Mantle convection and slab pull
- 17Which of the following is an example of ocean crust colliding with ocean crust?Aleutian Islands of Alaska
- 18Are divergent tectonic boundaries only found at mid-ocean ridges?No
- 19How were the Hawaiian Islands created?Mantle hot spot that upwelled magma to the surface to form underwater mountains that eventually grew to become islands
- 20Why did India not slide down back into the mantle during its collision with Eurasia?India was too buoyant (low relative density) to sink back into the mantle
- 21Siliceous and calcareous oozes are typically found...Away from the coasts in regions of very high biological activity
- 22T/F: Chemical isotope ratios found in fossils of marine shells can give some information about past ocean temperaturesTrue
- 23Analysis of fossil shells can yield information about...Species extinction through time, past levels of biological activity and past temperatures of the surface ocean
- 24Which of the following is propagated over long distances across the ocean by waves?Energy (not mass)
- 25Which wave process gives rise to the nice clean sets of waves of similar wavelength that come ashore in Hawaii from Alaskan storms?Wave dispersion
- 26What typically happens to wave energy as it approaches a coastal headland?The wave energy is focussed to produce stronger waves
- 27If you are caught in a rip current, what should you do?swim along the shore for 10 to 20 meters, then back to shore and call Bruce
- 28What sets the upper maximal limit on wave height?Wind speed
- 29What is a storm's fetch?It is the diameter of the storm system
- 30How fast does a tsunami wave propagate?About 500 miles per hour
- 31Is it always the case that coastal waters first recede away from the shoreline before a large tsunami finally moves in forcefully?No
- 32Which force is involved in the creation of the tidal bulge located on the side of the earth that is opposite the moon?Centripetal Force
- 33What orbit path does the moon take around the earth?The moon's orbit around the earth is at a 28 degree inclination relative to the equator
- 34According to the figure, semi diurnal tides are expected at...?mid-lattitude
- 35When do spring tides occur?During a full moon
- 36Why do tides occur in the ocean, but not in ponds and small lakes?Most tidal elevation comes from a lateral pull/pinch of water far to the side of the direct centerline between the earth and the moon. In small bodies of water, there is only the direct line under the moon so there is no tide
- 37Why do we get rotary tides?The combination of the Coriolis force and blocking by the continents
- 38Why do yo not get a significant tidal range in Hawaii?Hawaii is near an amphidromic point
- 39T/F: The atmosphere is warmed from above by the sun shining down from space- similar to a heat lamp shining down over a pot of waterFalse
- 40Which of the following is a good analogy for why we need to invoke a Coriolis force?A rubber ball sitting on the dashboard of a car that suddenly turns a corner
- 41If you have high pressure at 30N and low pressure along the equator, why do the surface winds not move straight southward form high to low pressure? Why do they instead turn to the east or west?They turned by the Coriolis force alone
- 42What happens to the surface ocean mixing depth in temperate regions as the surface ocean layer is warmed during the spring and summer periods?Mixing depth becomes shallower
- 43What is Ekman transport?The movement of a relatively thin (50m) slab of surface water in response to wind forcing
- 44How does the mound of surface water in the middle of the subtropical gyre get formed?The action of the trade winds and the westerly winds respectively drive the Eckman layers into the subtropical gyres
- 45How are the subtropical gyres forced to rotate in a clockwise direction in the northern hemisphere and counter-clockwise in the southern hemisphere?The trade winds and westerly winds pile water into the center of the gyres and this creates a downward pressure force that indirectly leads to the turning of the gyres
- 46If winds are blowing from south to north along the west coast of the US, would the Ekman Layer move onshore or offshore?Onshore
- 47How are deep-water masses identified?Based on characteristic temperature and salinity signatures
- 48How long does it take for deep ocean water to move from the North Atlantic to the North Pacific?About 2000 years
- 49What would happen if the Meridional Overturning Circulation (aka: Conveyor Belt Circulation) were to slow down due to climate change?It would decrease the transport of heat from the equator to higher latitudes
- 50What best describes net primary production?The net rate at which carbon moves into or out of phytoplankton cells
- 51The compensation light level refers to the level where...net primary production is zero
- 52What is true of small phytoplankton cells?They have a growth advantage at low nutrient concentrations
- 53Why are nitrogen, phosphorus, silica and iron the principle phytoplankton nutrients studies by oceanographers?These elements limit the growth of phytoplankton from time to time
- 54Subtropical gyres have low levels of primary production per square meter because...there is a persistent lens of warm low-nutrient surface water that depresses the thermocline and associated nutricline
- 55What is the major transport method that delivers iron to the ocean surface layer?dust blowing off of continents
- 56Primary production along the equator in the eastern Pacific and Atlantic is high because...The trade winds force an Eckman layer divergence that creates upwelling conditions, and the east/west tilt of the thermocline (deep in the west and shallow in the east)
- 57What is true of the critical depth?It is the depth at which phytoplankton can mix whereby net primary production averaged over the course of the day is zero
- 58What percentage of the oxygen you breathe can you thank the ocean for?50%
- 59Why is prey body size about 1/10 the size of the predators body size?A predator's mouth opening is about 1/10th of its full body size
- 60What is the exploitation efficiency of the copepod community that came out of winter diapaus and is now feeding in the early stages of the spring phytoplankton bloom of the North Atlantic?The Exploitation Efficiency is low
- 61Exploitation efficiency is the efficiency with which members of one trophic level are able to...find, capture and ingest all the members of a lower trophic level
- 62The main reason that coastal upwelling regions have much higher amounts of harvestable fish production each year is because...Answer= none of the above
- 63Epi-fluorescent microscopy and fluorescent DNA stains came into widespread use by oceanographers between 1975/1985 and this new technology dramatically increased oceanographers abundance estimates of...heterotrophic bacteria
- 64Where do heterotrophic bacteria get their energy and carbon to grow?Dissolved organic matter
- 65What is the main contributor to primary production in oligotrophic subtropical gyre regions?prochlorococcus
- 66The biological carbon pump is most efficient in...oligotrophic conditions
- 67What is the relative abundance of viruses to bacteria in the ocean10 viruses for every bacterium
- 68What do viruses do to modify the dissolved organic matter pool?They kill a lot of the heterotrophic bacteria and return the bacterial carbon back to the dissolved organic carbon pool
- 69What level of mortality can viruses inflict on marine bacteria?10-50% of total mortality- with grazing by protozoans making up the rest
- 70Is the virus that caused mass die-off of starfish populations a relatively new virus or has it been on the west coast for decades?It seems to have arrived on the west coast in just the past few years
- 71Which of the following is most true about rocky intertidal communities?Unique groups of species reside in distinct zones that are arranged sequentially from the lower intertidal to the upper intertidal
- 72What role does the starfish piaster play in rocky intertidal communities?Maintains high species diversity in the rocky intertidal
- 73What happens to kelp forests when sea otters are re-introduced?Kelp forests increase
- 74How sensitive are coral reefs being bleached by elevated ocean temperatures?Very sensitive: 1 degree above normal temperatures for a few weeks can cause bleaching
- 75At what point will coral reels begin to be significantly impacted by ocean acidification?When CO2 reaches 450ppm (about 20 years from now)
- 76Modern whales evolved from a land dwelling ancestor called Pakicetus. When was Pakicetus last running around on land?53 million years ago
- 77What analogy best describes the effect that increased commercial boat traffic has on whale populations?A noisy bar or restaurant that prevents social communication across appreciable distances
- 78Name three countries that currently use legal loopholes to continue to kill whales in spite of a general international moratorium on whaling?Norway, Iceland and Japan
- 79The two opposing forces that determine the phases of water are...Hydrogen bonding and thermal kinetic energy
- 80When winds blow over the surface ocean to cause evaporative cooling, what happens to the heat that leaves the ocean surface?It is transferred from the ocean to the atmosphere as latent heat in the form of atmospheric water vapor
- 81What determines surface ocean salinity for a given geographic location?The difference between evaporation and precipitation in that region
- 82Seawater salinity is initially set at the ocean surface. What happens when the sea water sinks into the ocean interior?The salinity remains unchanged except when mixing with other deep sea water masses of different salinity
- 83Where is surface ocean salinity typically highest?Subtropical gyres
- 84The conveyor belt circulation explains why nitrate and phosphate concentrations in the deep ocean are...low in the deep North Atlantic and high in the deep North Pacific
- 85What is expected to happen to the oxygen minimum zone as global warming increases?Oxygen levels in the minimum zone will decrease
- 86Oxygen concentration reaches a minimum level just below the sunlit layer of the ocean because...microbial respiration, fueled by dead organic material raining down from above, consumes oxygen down to low levels
- 87Why is carbon dioxide high in the deep ocean?Microbial consumption of organic matter associated with respiration produces carbon dioxide
- 88With business as usual emissions, what sort of timelines are we facing before polar seas become corrosive to calcium carbonate shells of planktonic organisms and coral reef growth is slowed or stopped altogether?In 20 to 30 years
- 89The concentration of CO2 in the atmosphere has oscillated up and down naturally over the past 800,000 years as an indirect response to small variations in the earths orbit. What have been the upper and lower limits to the natural oscillation of CO2 concentrations in the past and what is the concentration of CO2 today?It has gone from 180ppm to 280ppm for 800,000 years and is now at about 400ppm
- 90Are humans now powerful enough to prevent a future ice age from happening?Yes
- 91What is the level of certainty that the observed global warming is largely caused by humans?95% confidence level
- 92What is the estimated asset value, associated with low lying mega cities around the world, that are vulnerable to a 1 meter sea level rise by the end of the century?In the tens of trillions of US dollars range
- 93How soon might we see the Arctic Ocean completely ice free during the summer periods?Ice free by as soon as 2030
- 94One of the key goals contained in the COP-21 consensus statement, that was signed in Paris in 2015 by every single world leader of every nation, is that we should work to prevent the earth from warming beyond 2 degrees. What must happen to global CO2 emissions to stay below 2?The entire planet has to go net zero carbon emissions by 2050
- 95What is the key hurdle facing the Cornell'a plan to take the campus to zero carbon emissions by 2035?Developing earth-source heating for the campus
- 96According to guest speaker David Titley, how much of the earth's heat imbalance caused by greenhouse gas emissions has been taken up by the ocean?90%
- 97With regard to national security, what is one of the biggest concerns about extreme weather brought on my climate change?Increased social instability around the world due to increased droughts that enhance food insecurity
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- final Oceanography FlashCards sobre Oceanography I, criado por Lily McGovern em 04-12-2016.
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- Lily McGovern
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