Lecture 6

Question 1

Carbon

Answer 1

• 4th most abundant element
• organic (reduced and reactive) or inorganic (oxidized and less reactive, CO2)

Question 2

organic carbon _______s to create _______

Answer 2

oxidizes, inorganic carbon

cellular respiration, opposite for photosynthesis

Question 3

3 species of carbon in the ocean

Answer 3

co2 (acidic), HCO3 bicarbonate (neutral), CO3 carbonate (basic)

Question 4

residence time

Answer 4

average length of time a molecule will cycle through a reservoir in a steady state

Question 5

residence time of carbon shortest to longest

Answer 5

CO2, mixe dlayer of ocean, land/bio, deep

Question 6

characteristic response time

Answer 6

how long it takes for a reservoir to react once it falls out of a steady state

Question 7

CO2 fertilization

Answer 7

Photosynthesis rates increase to compensate for increasing CO2 in order to return to steady state

residence time = characteristic response time

Question 8

short term carbon cycle

Answer 8

• Photosynthesis move inorganic carbon into organic carbon system
• Anaerobic respiration occurs in absence of O2 (methanogenesis)
• Aerobic respiration of decomposers
• methane oxidation
• respiration of plants and animals

Question 9

primary productivity

Answer 9

○ Autotrophs
○ Amount of organic material produced by photosynthesis in a unit area over a unit of time (kg/m2/yr)
○ Most of biomass in terrestrial landscapes is stored in tree trunks and roots (big forests)

Question 10

the biological pump

Answer 10

the ocean
taking carbon from mixed layer/surface and transport to deep layer
- through phytoplankton and zooplankton

Question 11

what happens to upper ocean in the biological pump

Answer 11

depleted of nutrients and dissolved carbon but rich in oxygen and photosynthesis

Question 12

deep oceans in the bio pump and carbon cycle

Answer 12

nutrient rich as organic matter settles and use O2 to decompose and CO2 is liberated
- CO2 rich and colder

Question 13

where does most productivity occur

Answer 13

along the coasts
- more mixing going on so more stuff available and more mixing towards poles due to reduced thermal gradient

Question 14

carbon sinks vs sources

Answer 14

carbon sinks - coastal and cold water
sources - coastal and warm waters

Question 15

what happens when co2 enters ocean

Answer 15

dissolves in water, reacts into carbonic acid, liberates hydrogen and bicarbonate ion, and further into hydrogen and carbonate

Question 16

ocean acidification process

Answer 16

• Adding CO2 slowly decreases ph because it is using up carbonate
• Decreases buffering capacity of seawater and drives system to the left

Question 17

Leaks

Answer 17

Organics sequestered into sediments
- carbons that survive dissolution leak into rock cycle for long term sequestration

Question 18

carbon compensation depth

Answer 18

depth in the ocean at which CaCO3 cannot exist

Question 19

long term carbon cycle

Answer 19

carbonate rock formation, storage in rocks, weathering,

Question 20

carbonate rock formation

Answer 20

areas above CCD will form carbonate rocks, eventually buried by ocean conveyor belt past the CCD

Question 21

carbon stored in what kinds of rocks

Answer 21

limestone, sed rocks, fossil fuels, soils, sediments

in that order of most to least

Question 22

types of weathering

Answer 22

organic in sedimentary rocks - oxidization
chemical weathering of carbonates and silicate rocks - when CO2 in rain reacts

Question 23

Tectonic forcing

Answer 23

moving continents change climate on long time scales
- alters distribution of land masses and climate patterns
- more uplift means more weathering and more CO2 drawdown

Question 24

• Carbon isotopes tell us

Answer 24

○ Changes in carbon cycle
○ Estimate oxygen concentrations
- Rough estimates of partial pressure of CO2

Question 25

Three main isotopes of carbon

Answer 25

○ Carbon 12 - stable, light - 99% of naturally abundant carbon
○ Carbon 13 - stable - 1%, heavier means more C13 than the standard, positive values
- Carbon 14 - radioisotope - super small

Question 26

Plants prefer C__ resulting in negative delta C__

Answer 26

12, 13

Question 27

carbon 13 ___ in summer and ___ in winter

Answer 27

increases, decreases, because C12 gets used by plants more in summer

Question 28

buried organic carbon is ____ light/heavy

Answer 28

light, so the left over in atmosphere and oceans is heavy

the faster organic carbon is buried, the heavier the carbonates will be