Oceanography Final

How do stars form?

Stars started forming after the intense heat of the Big Bang cooled and cold hydrogen gas 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 the object makes its interior hot enough to ignite thermonuclear fusion reactions.

Our understanding of where the water that fills the Earth’s oceans came is still of some scientific debate, but most scientists currently think it was likely brought to earth by comets

False

How quickly did life appear on Earth after the Earth cooled and the oceans filled?

Remarkably quickly (less than 500 million years).

When did life on land first appear?

550 million years ago

When did life on Earth transition from being just simple prokaryotic organisms floating around in the ocean to more complex eukaryotic organisms and multicellular organisms?

2 billion years ago

Which came first, evolution of bacterial photosynthesis and the associated production of oxygen or the evolution of multicellular organisms?

evolution of bacterial photosynthesis and oxygen came first.

Which type of crust is denser?

oceanic

What evidence did Alfred Wegner use 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.

What kind of tectonic process takes place in deep sea trenches?

This is where old oceanic crust is sinking back into the mantle.

Which geologic feature is a result of oceanic crust colliding with continental crust?

Andes Mts

Where are siliceous and calcareous oozes typically found?

Away from coasts in regions of high biological productivity.

Which wave process gives rise to the nice, clean sets of waves that have similar wavelength that come ashore in Hawaii from Alaskan storm?

dispersion

What typically happens to wave energy as it approaches a coastal headland?

The wave energy is focused to produce larger waves.

How fast does the tsunami wave propagate?

500 miles per hour

What is a storm’s fetch?

diameter of storm system

When do Spring Tides occur?

full moon

Why do we get rotary tides?

The combination of Coriolis force and blocking by continents.

If you have high pressure at 30ºN and low pressure along the equator, why do the surface winds not move in a straight line southward from high to low pressure? Why do they instead turn to the west?

They are turned by the Coriolis force.

How is the mound of surface water in the middle of the subtropical gyre formed?

The action of the Trade Winds and the Westerly Winds collectively drive an Ekman Layer convergence into the middle of the subtropical gyre

What drives subtropical gyre rotation?

A center of high pressure under a mound of water drives ocean currents radially outward and these currents are deflected by the Coriolis Force

If winds are blowing from north to south along the west coast of the United States (e.g., the Washington, Oregon and California Coasts), would the Ekman Layer move onshore or offshore?

offshore

How is the age of bottom water in the deep ocean measured?

14C concentration

Which statement best describes the current state of scientific knowledge regarding the possibility that the Atlantic Meridional Overturning Circulation (AMOC) might collapse this century?

Scientists have modest but steadily growing concern that AMOC could collapse this century.

What happens to the Walker Circulation Cell during the transition from normal conditions to El Niño conditions?

The Walker Cell slows down or reverses.

What happens to the Warm Pool during the transition from normal conditions to El Niño conditions?

The Warm Pool propagates from the Western Pacific (near Australia) to the Eastern Pacific (near Peru).

During an El Niño event, biological productivity off the California coast can be expected to increase?

False, El Niño events typically lead to a decrease in primary production that, in turn, lowers growth for the rest of the food web.

How can the effects of El Niño conditions in the Pacific be transmitted to the far reaches of the globe?

Variation in the position of the Jet Stream in the atmosphere

With regard to the global carbon cycle, how does the magnitude of CO2 sequestered

by the global ocean through photosynthesis and, separately, the magnitude of CO2

released by the global ocean through respiration compare to the magnitude of CO2

emitted by humans through fossil-fuel burning?

Ocean respiration and ocean photosynthesis are each much larger than

human emissions

Which light level produces zero Net Primary Production?

compensation light level

Which type of phytoplankton has the growth advantage at low nutrient

concentration?

small cells

Which nutrient limits the growth of phytoplankton in the Southern Ocean?

iron

Why is primary production in the Eastern Equatorial Pacific higher than in the

Western Equatorial Pacific?

The thermocline is shallower in the Eastern Equatorial Pacific.

Why do coastal upwelling regions experience seasonal increases in primary

production?

Because the winds driving upwelling is seasonally variable.

Where is the critical depth located relative to the compensation depth?

deeper

If phytoplankton mix a little bit below the compensation depth, then net primary

production averaged over the course of a day will be negative.

False

What do oceanographers mean when they say that pelagic ecosystems are strongly

size structured?

They mean that body size is the dominant factor that determines what

trophic level any given animal species will reside in.

What is the level of Exploitation Efficiency for the case of small grazers feeding on

small phytoplankton in tropical regions?

high

Given a Trophic Transfer Efficiency of 10%, how many units of fish would be

produced each year if you started with 1000 units of phytoplankton?

phytoplankton > zooplankton > fish

10

Where is overall production of harvestable fish greatest?

coastal region

What do heterotrophic bacteria use for their source of energy and carbon?

dissolved organic matter

Where does the Biological Carbon Pump operate most efficiently?

eutrophic regions

What factor or factors determines where a given species resides in the rocky

intertidal?

all of the above

What happens to the level of biodiversity in the rocky intertidal region when the

starfish Pisaster is removed?

biodiversity decreases

What is meant by the term Trophic Cascade?

It describes the alternating decrease-increase-decrease in the

abundance of organisms in adjacent trophic levels.

What is responsible for the massive declines in kelp forests off the California coast

over the past decade?

sunflower starfish decline due to disease

What percentage of a coral’s nutrition comes from its Zooxanthellae symbionts?

60-90%

What resource is in short supply in coral reefs and under stiff competition with other

coral species?

space

What happens when coral reefs are overfished?

It reduces herbivory on macro algae and allows the macro algae to

overgrow and smother coral species.

How much coral cover has already been killed off over the past 150 years?

50%

What percentage of corals will be lost if global warming reaches 2 ºC?

>99%

What unique skeletal feature is used to connect all of the transitional fossils

between Pakicetus and modern whales?

ear bone

What time of year should you visit Hawaii if you wanted to see humpback whales?

winter

Off-shore oil exploration uses air guns to blast noise that penetrates deep into

ocean sediments in search of subsurface pools of oil. The magnitude of the air guns

is on the order of dynamite exploding. How often do these air guns blast noise into

the ocean?

once every 10 seconds for several months

What property of water allows it to form hydrogen bonds with adjacent water

molecules?

The polar charge distribution with one side of the molecule having a

slightly positive charge and the other side having a slightly negative

charge.

What two opposing molecular forces/energies determine the three phases of water

(solid, liquid and gas)?

H bonds and thermal kinetic energy

When a given amount of heat energy is added to the surface ocean, the temperature

does not rise nearly as much as it would if the same heat energy were added to land

or atmosphere. Why is this the case?

Water has an exceptionally large specific heat capacity.

When water vapor is transported by the winds it is transporting heat energy stored

as latent heat that will eventually be turned back into sensible heat when it

condenses back to rain at a new location.

true

What determines surface ocean salinity for a given geographic location?

The difference between Evaporation and Precipitation in the region

Where is surface ocean salinity lowest?

Subpolar North Pacific

What happens to the concentration of nitrate and phosphate in deep ocean waters

(4000 meter) as the deep waters move from the North Atlantic to the North Pacific?

increases

What causes of an oxygen minimum zone to form just below the sunlit layer of the

ocean?

microbial respiration

Why does the oxygen concentration in deep ocean waters (4000 meters) decrease

as the deep waters move from the North Atlantic to the North Pacific?

microbial respiration along 2000 year journey from Atlantic to Pacific

Why is CO2 low in the surface ocean?

photosynthesis in surface ocean

How much of the cumulative CO2 emitted to the atmosphere from fossil fuel

burning has the ocean taken up?

about 30%

The ocean surface is 60% more acidic today relative to the pre-industrial level.

false

What will happen to the acidity of the surface ocean if you bring deep ocean water

to the ocean surface?

increase

Why are polar seas especially vulnerable to ocean acidification?

cold water absorbs more CO2 than warm water

With “business-as-usual” fossil fuel emissions, how soon will polar seas become

corrosive to the calcium carbonate shells used by planktonic organisms that form

an important part of the base of marine food webs?

20 to 30 years

How much has atmospheric CO2 concentration increased since the beginning of the

industrial era?

about 50%

How much does anthropogenic methane contribute to the energy imbalance in the

earth system relative to the contribution made by CO2?

Methane’s forcing is about 50% as strong relative to CO2

According to Professor Howarth, we know the total methane emission to the atmosphere is about 570 Tg per year. How much of this total is due to the emission of ancient methane from natural seeps?

0%

After some careful bookkeeping, Professor Howarth showed that the observed increase in atmospheric methane over the past several decades is caused by anthropogenic sources of methane. The anthropogenic source is made up of ancient methane from natural gas production that uses hydraulic fracturing methods and new methane from animal agriculture. Professor Howarth went through some additional bookkeeping to narrow down the likely source of this anthropogenic increase in methane emissions. What was his conclusion?

It was caused by unconventional shale gas extraction (hydraulic fracturing extraction method).

According to Professor Robert Howarth, why is nuclear energy not a reasonable solution to getting New York State to net zero emissions?

all: The nuclear waste storage and disposal is a problem. The cost of building nuclear power plants is very expensive relative to solar and wind. It takes much longer to deploy nuclear power plants relative to solar and wind deployment

What is the source of the heavy metal pollution in the ocean?

Smokestacks from unregulated factories and coal-fired power plants that inject heavy metals into the atmosphere that are transported over the ocean and then wash from the atmosphere and into the ocean when it rains.

What is the mechanism that is responsible for plastic pollution being concentrated to high levels in subtropical gyres?

Ekman Transport forced by the Trade Winds and the Westerly Winds

How does nutrient pollution lead to so-called “Dead Zones”?

Excessive nutrients allow phytoplankton to grow to exceptionally high abundances and when the phytoplankton die and sink to the bottom, they become food for bacteria that draw down oxygen levels to zero.

According to Professor Allmon, when did Earth’s 6th mass extinction likely begin?

thousands of years ago

In the Oil on Ice video, what large migratory animal will likely be impacted by oil drilling in the Arctic National Wildlife Refuge?

porcupine caribou

How has the scope of the Clean Water Act been expanded and shrunk between US Presidential Administrations?

By reinterpreting the definition of navigable waters

In 2010, The Obama Administration implemented, by executive order, a new National Ocean Policy (NOP) based largely on the recommendations made by the Pew Charitable Trust’s Oceans Commission and the U.S. Commission on Ocean Policy. Regional Planning was a centerpiece of this new policy. What did this new policy approach intend to do?

Bring order to the chaos by bringing all stakeholders together where they can weigh the priorities of users of the coastal environment as a whole, rather than the piecemeal first-come-first-served approach used in the past.

. The Law of the Sea Convention (Treaty) has never been ratified by the United States Senate. Senate ratification is being blocked because it is opposed by a wide range of stakeholders that includes the US Navy, large oil and gas interests and international shipping interests

false

When the Ecological Footprint for each individual on earth is summed over the entire human population for 2024, the total is 1.7 planet earths. What does this mean?

It means we are drawing on earth resources at a rate that is 70% more than earth needs to sustain the wellbeing of future generations.