Binder notes

Question 1

AOU equation

Answer 1

AOU = [O2]sat - [O2]obs

Question 2

Equation to calculate changes in nitrate and phosphate from AOU

Answer 2

P = Po + (AOU/138)
N = No + 16*(AOU/138)

Question 3

If there is no calcium carbonate production or dissolution, does carbonate alkalinity change?

Answer 3

No.

Question 4

What elements can be limiting in the ocean?

Answer 4

Fe, N, P, Si

Question 5

What microbe mediated respiratory process yields almost as much energy as aerobic respiration?

Answer 5

Denitrification

Question 6

Why is aerobic respiration the favored OM oxidation pathway when O2 is available?

Answer 6

It has the greatest energy yield.

Question 7

Which ratio(s) are more variable C:P, N:P, or C:N

Answer 7

C:P and N:P

Question 8

What are two tracers can be used to date younger water masses?

Answer 8

CFCs and C-14

Question 9

What is the effect of denitrification on the Redfield ratio?

Answer 9

Denitrification strips nitrate from the water column, which decreases the N:P ratio.

Question 10

Why are preformed nutrient concentrations characteristic of HNLC regions?

Answer 10

Some areas are nutrient limited. Regions like Sub Arctic Pacific, Equatorial Pacific, and Antarctic ocean are iron limited. Thus, not all of the nutrients are used up by primary productivity.

Question 11

What are preformed nutrients?

Answer 11

Nutrients that were present in a water mass before downwelling.
Preformed nutrients = total nutrients - regenerated nutrients

Question 12

What does a positive AOU value mean?

Answer 12

O2 used up through aerobic respiration. O2(sat) is greater than O2(obs).

Question 13

Why does an increase in AOU relate to an increase in nitrate, phosphate, and carbon dioxide?

Answer 13

Because nitrate, phosphate, and carbon dioxide are the inorganic products of OM degradation.

Question 14

What do microbes use as an e- acceptor during aerobic respiration?

Answer 14

Oxygen

Question 15

What is the oxidation number of an element in its free uncombined state (or combined with itself)?

Answer 15

Zero.

Question 16

What does the oxidation state represent?

Answer 16

The total number of electrons which have been removed from an element (a positive oxidation state) or added to an element (a negative oxidation state) to get to its present state.

Question 17

What is the oxidation state of a monoatomic or polyatomic ion?

Answer 17

The charge of the ion.

Question 18

Which N form contains nitrogen at its highest oxidation state? What is N’s oxidation number in that form?

Answer 18

Nitrate. +5

Question 19

Which N form contains nitrogen at its lowest oxidation state? What is N’s oxidation number in that from?

Answer 19

Ammonium, -3

Question 20

Simple forward/backward reaction for photosynthesis/respiration

Answer 20

CH2O + O2 CO2 + H2O

Question 21

pH (water): meaning and formula

Answer 21

potential hydrogen ions from the disassociation of water
Negative log of hydrogen ion activity
pH = -log(aH+)

Question 22

Reaction of CO2 + H2O

Answer 22

H2CO3

Question 23

Four parameters that define carbonate speciation

Answer 23

TCO2, pCO2, TA, and pH

Question 24

Why is pH considered the master variable?

Answer 24

Because it drives the relative distribution of carbonic acid, carbonate, and bicarbonate.

Question 25

Why is pH=7 considered neutral?

Answer 25

Because the concentration of hydrogen ions equals the concentration of hydroxide ions produced from the disassociation of pure water at standard temperature and pressure.

Question 26

Why is CO2, by definition, an acid?

Answer 26

Because when dissolved in water it produces hydrogen ions.

Question 27

What happens, in terms of the carbonate equilibrium equations, when the pH of SW is lowered?

Answer 27

The addition of hydrogen ions push the equilibrium expressions to the towards the left, which favors CO2* and consumes carbonate and excess H+.

Question 28

Effective partial pressure of CO2 in SW

Answer 28

The partial pressure that the gas would have in the overlying atmosphere if an equilibrium is reached with the concentration of [CO2*]

Question 29

What is the dominant form of dissolved inorganic phosphorus in salt water?

Answer 29

HPO4(2-) phosphoric acid

Question 30

What drives DIP speciation?

Answer 30

pH

Question 31

Equation for TCO2 if OM remineralization is equal to CaCO3 dissolution

Answer 31

TCO2 = TCO2o + 2*(106*AOU)/138

Question 32

Equation for TCO2 if all OM remineralization and no CaCO3 production or dissolution?

Answer 32

TCO2 = TCO2o + 106*(AOU/138)

Question 33

If CaCO3 production or dissolution is of equal importance to OM remineralization, then what is the ratio of ALK to TCO2? How would I get an ALK value from TCO2?

Answer 33

1:1 | ALK = TCO2

Question 34

What sets the regeneration ratio of inorganic species in the open ocean?

Answer 34

Elemental ratio of sinking OM

Question 35

What makes nitrogen gas stable, but difficult to incorporate by organisms?

Answer 35

Triple bond

Question 36

What is the redox cascade of electron acceptors in sediments?

Answer 36

Oxygen, nitrate, Manganese(IV), Iron(III), sulfate, carbon (methanogenesis)

Question 37

What are four likely marine N cycle controls?

Answer 37

1) factors promoting denitrification/anammox 2) suboxic conditions (poor ventilation/high respiration) 3) availability of nitrate 4) availability of OC

Question 38

How might low O2 in Peru lead to a deviation from the Redfield ratio?

Answer 38

Low O2 leads to low nitrate, but doesn't affect phosphate

Question 39

What does the AOU of a water sample represent?

Answer 39

The sum of the biological activity that the sample has experienced since it was last in equilibrium with the atmosphere.

Question 40

Where have iron experiments occurred?

Answer 40

Galapagos, Southern Ocean, sub arctic.

Question 41

Primary productivity

Answer 41

photosynthetic formation of organic matter

Question 42

gross primary production

Answer 42

the amount of carbon fixed (CO2 converted into organic matter) by photosynthetic organisms (per unit time per unit volume)

Question 43

Net primary production

Answer 43

the total carbon fixed minus the amount respired by the primary producer.