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GeoSci 40 Midterm
Terms in this set (96)
What is the correct rank order of elements and molecules from highest to lowest concentration in seawater?
Cl, Na, SO4, Mg, Ca, K
What is latent heat?
the energy required to change ice to liquid water and the energy released when water vapor condenses to form rain
When scientists carry out investigations, what do they do?
construct one or more hypotheses, make observations and collect data, test the hypothesis by trying to disprove it, & evaluate and change hypotheses on the basis of results
When did ocean water most likely form?
from emission (degassing) of materials (volatiles) from Earth's interior
Goldilocks and Water on Earth: Recently a team of astronomers announced what?
they had detected two Earth-sized planets circling very close to a star called Kepler-20
The latent heat of fusion (melting) for water is 80 cal per gram. How much heat energy is required to melt 10 grams of ice?
What does Rachel Carson suggest?
rain and other factors weather the continents and that rivers deliver dissolved rock (including elements such as Na, Ca, Cl) to the world ocean, which causes changes in ocean chemistry through time
What does the "Goldilocks Principle" suggest?
the origin of water on Earth suggests that: 1) Earth has just the right position in the solar system - not too close to the sun and not too far away - and 2) When it was forming, Earth had just the right mass, large enough to retain water vapor.
Why does water have such unusual characteristics?
water molecules have polar (unequally distributed) charge
What is seawater chemistry influenced by?
What is ocean chemistry influenced by?
inputs such as river water and volcanic gases, outputs such as evaporates and interaction of seawater with the seafloor, rock weathering, & marine life including plants and animals
What are the thermocline, halocline, and pynocline?
names for the region between ocean surface water and deep water
Is the chemistry of ocean water the same as river water?
Can more gas be dissolved in cold seawater or warm seawater?
A water molecule may evaporate from the ocean, become part of a cloud and then become a rain drop that becomes part of a river and flow back into the Ocean. How long is the average residence time for a molecule to make this trip?
about 4,000 years
What is the residence time for an element in seawater?
it is given by the ratio of the total amount of the element in seawater divided by the input rate
What is true about the layers of the ocean?
the ocean is stratified into layers, such that shallow water has different properties than deep water
What is true about the density of seawater?
it increases as temperature falls and salinity rises
What does the water cycle involve?
evaporation, precipitation, & condensation
Latitudes above about 40 degrees N and S _______ more solar energy than they lose
What does uneven heating of the Earth's surface result in?
belts of low and high pressure, which generates a three-dimensional pattern of winds, winds that include Easterlies, Westerlies, and upper atmosphere winds such as the Jet Stream, and a surplus of solar energy received in the tropics relative to high latitudes
Why do marine animals break down water molecules?
to obtain oxygen for respiration
How is the ocean stratified?
with the densest water below and less dense water above
What are the three major circulation cells in each hemisphere (with the correct latitudes)?
Hadley (0-30 degrees), Ferrel (30-60 degrees), Polar (60-90 degrees)
What does the Coriolis effect play a role in?
deflection of wind and ocean currents to the right in the northern hemisphere, deflection of wind and ocean currents to the left in the southern hemisphere, trade winds that blow east to west in both the northers and southern hemispheres, and formation of the large-scale ocean currents called gyres
Large-scale gyres in the major oceans involve surface currents that flow in what direction in both the northern and southern hemispheres?
Global oceanic circulation involving deep water and surface water motion acts to do what?
regulate Earth's surface heat and climate
Deep-water ocean circulation is driven by what?
temperature and salinity contrasts between water masses
What does the Coriolis Effect arise from?
conservation of momentum and Earth's rotation
Large-scale gyres in the major oceans bring ______ water from the tropics to the poles and _______ water from the poles to the tropics
warm ; cold
What happens when water piles up in the interior of a gyre?
it causes a slight surface slope and pressure gradient oriented toward the outside of the gyre
Where is oceanic deepwater formed today?
the Weddell Sea and the Norwegian-Greenland Sea
What is true about the temperature-depth relationship for seawater?
tropical regions have the highest surface water temperature & deep water has about the same temperature for each latitudinal zone
What direction is the ind circulation around a low pressure system in the northern hemisphere?
What has happened to the world fish production in the past 50 years?
it has decreased
What are Red Tides?
they indicate blooms of potentially toxic dinoflagellates, occur mainly in the summer, and can be caused or exacerbated by aquaculture
According to the trophic pyramid,what does it take to grow 1 kg of a top level predator-consumer such as tuna?
10,000 kg of phytoplankton
What are some examples of organic matter?
phytoplankton, apples, & whales
Why do Baleen Whales migrate large distances to feast in the Bering and Chukchi Seas?
because conditions are optimum for growth of plankton and krill
Why is phytoplankton production often very high in the open ocean?
because of rapid upward mixing of deeper waters into the photic zone
What are phytoplankton?
photosynthetic algae (plants) that live in the ocean's photic zone and are an important source of energy (food) for nearly all ocean life; they consume carbon dioxide & produce oxygen
Marine phytoplankton are photosynthetic organisms. In the photic zone of the ocean, what can their growth rate be limited by?
availability of nutrients and availability of light
Why is deep ocean water essential to phytoplankton growth?
it is rich in nutrients
Is the salinity and temperature of ocean deep water similar to that of shallow surface water?
Rachel Carson suggested that rain and other factors did what to the world ocean?
weather the continents and that rivers deliver dissolved rock (including elements such as Na, Ca, and Cl)
Is there more dissolved carbon dioxide in the deepwater of the ocean or the surface water?
What is the sigma_t of 1.023?
On a temperature vs. salinity chart, which has a higher density: 1.022 or 1.023
The latent heat of fusion (melting) for water is 80 cal per gram. How much heat energy is required to melt 1 gram of ice?
What is seawater density determined by?
salinity and temperature
What are the two most abundant elements in seawater?
Cl and Na
The average salinity of the world ocean is ___ parts per thousand?
What does the term sensible heat and heat capacity refer to?
the heat necessary to change the temperature of a substance
What does the term latent heat refer to?
the heat necessary to change the phase of a substance (ex. from solid to liquid)
Does water have a higher heat capacity than land?
For gases dissolved in seawater, solubility...
is higher in colder water and decreases as temperature rises
How does the Earth receive most of its energy?
radiation from the sun
The density of seawater...
increases as it cools form 30 deg C to 5 deg C and increases as temperature falls and salinity rises
What is true of the 17 billion Earth-sized worlds lurking in the Milky Way?
most are so close to their stars that they would be far too hot for life as we know it
When you gaze up on a clear night at the stars, at least 70% of stars we see have what?
a planet, whether it is a small rocket planet or a gas giant
What does a hurricane do as it builds up?
it builds energy as it moves across the ocean, sucking up warm, moist tropical air from the surface and dispensing cooler air aloft
What does the thermocline correspond to?
What does the halocline correspond to?
What does the pynocline correspond to?
What types of wavelengths of visible light penetrate deeper?
shorter (blue) wavelengths penetrate deeper than longer (red) wavelengths
The growth and survival rate of phytoplankton depends on what?
temperature, salinity, predator-prey relationships, and the correct density that will allow them to float passively in the photic zone
Diatom Reproduction by Fission
cross section of diatom creates new outer walls which create reproduction
depth at which rate of photosynthesis = rate of respiration
Growth (production of biomass)
requires net photosynthesis
Where does most biomass production occur in the ocean?
in the upper 40% of the photic zone where light intensity is greater than 20% of surface intensity
Where do photosynthesis and respiration occur in the ocean?
surface ; deepwater (respectively)
Paralytic Shellfish Poisoning
can result from eating clams, mussels, or other shellfish that have ingested algae laden with a family of poisons called saxitoxins (causes suffocation and death by blocking nerves)
Why does the velocity of water decrease with depth?
because of the friction between water molecules and the wind moving surface water
What does the Ekman spiral predict?
that net motion of surface water is 90 degrees to the right of the wind direction in the northern hemisphere
Gyres are a result of...
wind direction, Coriolis effect, & Ekman spiral effect
What are the major groups of phytoplankton?
diatoms, coccolithophroids, & dinoflagellates
What are diatoms?
shells made of opal
What are coccolithophroids?
shells made of calcite
What are dinoflagellates?
bodies that are organically walled
How do algal blooms occur?
from fish farm waste which feeds blooms
What are remedies to HABs?
spray fine clay over the surface; surfaces of clay (montmorillonite) attracts algal cells and settles to the bottom sweeping out HAB for a while
What are Red Tides caused by?
a rapid surge of nutrients into photic zone, longer days and more sunlight, warm water (increases reproduction rate)
What are the causes of destruction to the fish industry?
industrialized fishing, habitat destruction, pollution, & climate change
What promote phytoplankton growth and bloom?
light, nutrients, & upwelling of deep water
Plankton growth is driven by the supply of deep water into the photic zone through what?
storm or density-induced mixing, wind-driven upwelling, and river runoff to the ocean
About what percent of marine fish stocks are fully exploited, over exploited, depleted, or slowly recovering?
About what percent of each catch of fish are killed and discarded in industrialized fishing?
How many major fishing grounds are in serious decline?
9 out of 17
How do phytoplankton acquire nutrients and eliminate waste?
osmosis --> nutrients (diffuse into cell as they are depleted) --> waste (products diffuse out of cell as they build up)
passive diffusion of molecules in the direction of chemical dradients from high to low concentration
What percent of energy is lost to respiration through the food chain?
99% of oceanic fish production occurs in 10% of the ocean area. What areas are these and why does this happen in those areas?
shelves & upwelling zones ; because the production of phytoplankton (organic matter) is highest per unit area in these areas and because food chains are shorter (fewer trophic levels) so there is less overall energy lost (efficiency is greater)
Where is the Zone of Light penetration?
-70 meters ; photosynthesis and vision
-600 meters ; vision only - not enough sunlight for photosynthesis
below 600 meters ; no sunlight
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