Oceanography Final UCSB

true or false: Because the residence time of atmospheric CO2 is 3.4 yr, the CO2 we emit has very little effect on atmospheric CO2 levels.

false

true or false: Current climate trends can be explained based on natural causes (e.g., sunspots & volcanic eruptions).

false

true or false: Organic tissue requires the same amount of both nitrogen and iron.

false

After sediments and rocks, what is the next largest reservoir of carbon on Earth?

Ocean

Glacial cycles in atmospheric CO2 concentrations are most likely caused by changes in:

Ocean carbon storage

General Circulation Models (GCM)

used to make projections of future climate change for different emission scenarios

during an El Nino, the east equatorial Pacific is ___________ than usual.

warmer

CO2 storage of the deep ocean increased because of:

-Colder oceans -More primary productivity (nutrients from dust) -Deep ocean stratification (less vertical mixing)

true statements about gyre circulation

-Gyres result from the combined influences of wind, Coriolis force, and continents -Gyre circulation primarily affects the top 100 meters of the ocean -Gyres rotate in different directions in the northern and southern hemispheres. -A single gyre can move more than 50 times as much water as all the rivers on Earth.

Which of the following statements accurately describes remineralization?

-It occurs in both the surface and deep ocean. -It consumes oxygen and produces CO2. -It converts organic matter into inorganic nutrients. -Its chemical reaction is the reverse of photosynthesis.

true statements related to thermohaline circulation

-It takes about 1000 years for deep water to circulate around the Earth. -Deep water forms at high latitudes. -Deep water forms in the North Atlantic but not the North Pacific.

Warming in the Arctic

-Positive albedo feedback as sea ice and snow melt. -Positive feedback with water vapor as Arctic air becomes more warm and humid, producing a stronger local greenhouse effect. -8 degrees C arctic warming

these 4 were associated with weaker thermohaline circulation during the last ice age

-Santa Barbara cooled -Southern Hemisphere warmed -Shifts in the location of tropical rainfall -North Atlantic cooled

temperature change can be caused by changes in

-Solar input -Reflected energy (albedo, aerosols) -Long-wave output (greenhouse effect)

sulfate aerosols

-They increase Earth's albedo, producing a cooling effect -They can be produced by burning coal -They can be produced by volcanic eruptions

Upwelling

-Upwelling of deep water occurs when wind-driven surface currents push surface water away from shore or the equator. -This brings cold, nutrient-rich deep water to the surface, creating localized regions of high primary productivity.

Heterotroph

-consumer -herbivores (primary consumer) -carnivores (secondary and up)

Which process contributes to deep water formation by increasing the density of surface water?

-cooling -evaporation -sea ice formation

Deep water is usually colder than surface water because

-deep water forms at high latitude -sunlight does not reach the deep ocean -cold water is denser than warm water -the thermocline prevents mixing between surface and deep water in most places

accurate descriptions of an El Nino event

-deepening of the thermocline in the east Pacific -weakened trade winds over the Pacific -an irregular recurrence interval that is difficult to predict

ocean circulation: vertically

-density stratified, thermocline -upwelling: coastal & equatorial -thermohaline circulation, NADW, AABW

Primary productivity

-measures the rate at which autotrophs turn carbon into organic tissue -measures the amount of energy available in a given ecosystem -has units of grams of carbon per square meter per year

autotroph

-primary producer -photosynthesis -chemosynthesis

Thermocline

-temperature boundary that separates the warm upper layer from the cold deeper water -difficult to mix across due to density change

What does the δ18O of CaCO3 from foraminifera measure?

-the amount of snow & ice on land -the ratio of two different oxygen isotopes

The deep ocean is more acidic (i.e., it has a higher CO2 concentration) than the surface ocean because:

-the deep ocean is colder -the deep ocean is under higher pressure -organic tissue remineralizes in the deep ocean

surface water

-warm=less dense -rapid mixing -nutrient depleted

Carbon dioxide makes up what percent of the atmosphere today?

0.04%

The approximate concentration of carbon dioxide in the atmosphere today is:

0.04%

Sverdrup 1sv=

1 Sv = 106 cubic meters per second

% of mass that is transferred across trophic levels

10%

What is the percent of H+ in the ocean relative to pure water?

10%

How many kilograms of phytoplankton does it take to support a 10 kg fish that is a third-level consumer (i.e., it eats small fish that feed on zooplankton that eat phytoplankton).

10,000kg

What is the average duration of glacial cycles over the past 800,000 years?

100,000yrs

How many kilograms of phytoplankton does it take to support a 10 kg fish that is a second-level consumer (i.e., it it eats zooplankton that eat phytoplankton).

1000

True or false: All isotopes eventually undergo radioactive decay.

false

Use the graph above to estimate the amount of CO2 in the atmosphere at the Last Glacial Maximum.

185ppm

How many kilograms of phytoplankton does it take to support a 200 kg shark that is a fourth-level consumer (The shark eats seals that eat fish that eat zooplankton that eat phytoplankton).

2,000,000

The Last Glacial Maximum

20,000 years ago

How many years from now might Arctic summer sea ice disappear if CO2 emissions continue to follow their current trend (i.e., the "business as usual" emission scenario)?

30 years (2050)

The Gulf Stream carries about as much water as:

50 times all the world's rivers

If atmospheric CO2 increases to 425 ppm, what percentage increase is that relative to pre-industrial levels?

50%

According to the Milankovitch hypothesis, what causes glacial cycles?

Changes in Earth's orbit and rotation axis

Thermohaline circulation

Circulation of the deep ocean due to density differences caused by temperature (thermo-) and salinity (-haline) changes

What would happen with no greenhouse effect?

Energy in = only short-wave energy from sun Earth's surface would be -19oC

limiting factor

Factor which limits primary productivity because of its availability relative to other necessary requirements. In ocean, this is most frequently: lack of light and nutrients

True or False: All deep water flows from north to south.

False

Heinrich Events

H-events occurred during extreme cold phases of D-O cycles in Greenland ice

How is the solubility of gases (including CO2) affected by making seawater colder?

More soluble

How were the IPCC's projections for future climate change created?

Scientists run computer models based on the physics of atmospheric and ocean circulation.

Density stratified

Surface water is less dense than deep water

Where is the oldest deep water?

The deep North Pacific because its surface water is too fresh to sink.

true or false

The only elements required for photosynthesis are carbon, oxygen, and hydrogen (and sunlight)

Rapid fluctuations in Greenland temperature were caused by changes in

Thermohaline circulation

One of the first indications that an El Nino event may be occurring is when

Warm water from near Australia migrates toward South America

What is a thermocline?

a temperature boundary between surface and deep water

When carbon dioxide dissolves in water, the water becomes slightly more:

acidic, pH is lower

Ocean currents distribute heat from equator to poles which

affects weather and climate

Acidic seawater makes CaCO3 more soluble

bad for organisms with CaCO3 shells

By how much is sea level expected to rise by the year 2100?

between 0.3-1.3 m

Marine primary productivity is lowest in which environment?

centers of gyres

True or False: Deep water convection is caused by heating at low latitudes.

false

What is a Sverdrup?

flow rate = 106 cubic meters per second

The California Current is caused by:

gyre circulation

ocean circulation: surface

gyres currents & climate

What are corals?

heterotrophs

as much as 2 km thick and thousands of years old

ice shelf

the edge of an ice sheet that extends into/over the ocean

ice shelf

forms by breaking off from glaciers or ice sheets

iceberg

The largest warming in the next 100 years is expected to occur:

in the Arctic

Where do you typically find the lowest oxygen concentrations in the ocean?

just below the euphotic zone

Which of the following cannot be classified as plankton?

kelp rooted to the sefloor

the two most common limiting factors in the ocean.

light and nutrients

shortwave or longwave: absorbed by greenhouse gases

long wave

shortwave or longwave: Infrared light

longwave

shortwave or longwave: emitted by Earth's surface

longwave

shortwave or longwave: emitted by the atmosphere

longwave

Why is eutrophication bad for marine organisms?

not enough oxygen

Seasons are caused by

the tilt of Earth's rotation axis

Which of the following has the lowest albedo?

ocean

Reef-building corals are only in what zone

photic zone

A primary producer describes organisms that get their energy from:

photosynthesis and chemosynthesis

Which type of organism is an example of a marine autotroph?

phytoplankton

Where is the density difference across the thermocline smallest?

polar regions

deep water is cold because it forms in the

polar regions

forms when the surface ocean freezes

sea ice

typically <2 m thick and lasts less than 5 years

sea ice

shortwave or longwave: Visible light

shortwave

shortwave or longwave: passes through the atmosphere unimpeded

shortwave

Over the last few decades Arctic sea ice extent has been:

shrinking faster than predicted

Milankovitch Theory

summer sunlight over ice sheets controls the size of ice sheets Changes in orbit shape & tilt affect summer insolation

Incoming energy from the sun has a short wavelength but outgoing energy from Earth has a long wavelength because:

the sun is hotter than the earth

Which of the following is most similar between marine and terrestrial ecosystems?

total primary productivity

5 major gyres

transport heat to europe NH move clockwise SH move counter-clockwise

True or False: some corals live in the deep ocean

true

True or false: Sulfate aerosols produced from burning coal act to make the climate cooler.

true

true of false: In the modern ocean deep water does not form at low latitudes.

true

true or false: High primary productivity is often associated with low oxygen levels just below the photic zone.

true

true or false: In the past, decreases in the rate of thermohaline circulation have caused dramatic cooling around the North Atlantic.

true

true or false: The atmospheric concentration of CO2 increased more rapidly from 2000-2012 than from 1958-2000.

true

true or false: The surface ocean typically has lower nutrient concentrations but higher productivity than the deep ocean.

true

At their current atmospheric concentrations, which greenhouse gas is responsible for the largest percentage of greenhouse effect?

water vapor