11

Question 1

how does the inorganic carbon, calcium, and carbonate dissolution affect us

Answer 1

buffering changes in ocean acidity
climate (ocean as a sink or source for CO2)
solubility of CaCO3 (geology, sediments, biology, calcareous organisms)
is affected by human CO2 emissions (ocean acidification)

Question 2

what are the species of inorganic carbon found dissolved in the ocean

Answer 2

CO2
H2CO3
HCO3-
CO32-

Question 3

when CO2 dissolves

Answer 3

it reacts with water to form carbonicacid H2CO3

Question 4

what changes pk1 and pk2 for formation of CO32-

Answer 4

decrease with T and weaker with S

Question 5

what is the use of bicarbonate HCO3-

Answer 5

acts as a buffer in the ocean

weak acid and base as it is part of two reactions

micture of acid HCO3- and its congugate base CO32- that resist change in pH when acid or base is added

Question 6

what is the pH of the ocean

Answer 6

7.4- 8.2

Question 7

distribution of carbonic acid forms

Answer 7

bc it is a weka acid, its distribution depends on pH and we can use this pH and the two Kas to estimate the distribution at diff pH values

Question 8

what is the distribution of the bicarbonate forms in the ocean pH

Answer 8

dominated by bicarbonate HCO3- (87%) and
second is carbonate CO32- 10%

Question 9

what species control air sea fluxes

Answer 9

CO2 at less than 0.5%

Question 10

inventory of DOC and POC

Answer 10

2%

Question 11

PIC invintory

Answer 11

0.01%

Question 12

how can we describe the carbon system

Answer 12

for a given T,S, P, we can describe it using any of the two systems

DIC
TA
pH
pCO2

we typically measure the first two to get the other two

Question 13

DIC=

Answer 13

[CO2]+[H2CO3]+[HCO3-]+[CO32-]

the first two terms typically equal less than 1%

Question 14

how is DIC measured

Answer 14

acidifying seawater to convert all carbonate and bicarbonate to cO2

bubbling inert gas through solution

measuring gas phase CO2

Question 15

what is TA

Answer 15

total alkalinity

total amount of charges available to buffer strong acids

units- eq/kg

stads for equivalent of a mole of charges

Question 16

what is TA=

Answer 16

[HCO3-]+2[CO32-] account for most of the cabonate alkalinity

+ means species that could remove H+
- are species that could add H+

Question 17

would a change in pressure or temp change DIC or TA

Answer 17

no bc we dont add or remove C or charges

Question 18

would uptake of 100umol/kg of 100 umol/ kg of CO2 from the atmosphere affect DIC or TA

Answer 18

dic would inc by 100 and TA wouldnt change

we added C but no charge

Question 19

what effect would formation of 25 umol/kg of CaCO3 have on DIC and TA

Answer 19

DIC decreases by 25 and TA decreases by 50 becasue removed CO32- but 2 charges

dissolution of CaCO3 would have the opposite effect

Question 20

what effect would formation of POC have on DIC and TA

Answer 20

both change exactly the same depneding on the POM ration if we assume the classic redfield ratio of C:N:P

if one species C then -106 = DIC bc youre forming

TA = 16+1= 17

Question 21

what effect would aerobic respiration/ decomposition of POM have on DIC and TA

Answer 21

the opposite effect of formation of POC

DIC would increase and TA would decrease

Question 22

what is the purpose of parallel lines on the DIC/TA graph

Answer 22

allows us to find the past CO2 and pH

Question 23

what happens graphically when you form Corg in the DIC/TA graph

Answer 23

decrease DIC and slightly increase alkalinity

Question 24

what happens graphically when you have CaCO3 dissolution or formation in the DIC/TA graph

Answer 24

dissolution- increases DIC and TA

formation- decrease DIC and TA

Question 25

why is the formation and burial of CaCO3 not a net sink for atm CO2

Answer 25

formation of CaCO3 reduces alkalinity more than DIC-

leads to lower pH

shifts larger portion of DIC in surrounding water to CO2

leads to higher pCO2 in water

less room in water for CO2 from air

Question 26

what are the polymorphs of calcium carbonate

Answer 26

aragonite

calcite

same chemical composition but diff crystal structures

aragonite is stronger physicially but more chemically vulnerable

Question 27

what causes the formation of one form over the other of the different polymorphs of calcium carbonate

Answer 27

depends on the Mg levels in the ocean

high Mg- aragonite seas

Question 28

what happens when Mg subs for Ca

Answer 28

high Mg calcite which is less stable and very soluble

Question 29

what kind of reaction is the incorporation of Mg as an impurity in calcite

Answer 29

endothermic process

more likely in warmer waters

Question 30

what is the use of formatino of Mg calcite being endothermic

Answer 30

using the Mg/Ca ratio in shells of microfossils as a paleothermometer

Question 31

how does CaCO3 enter the oceans

Answer 31

through riverine inputs

or

percipitated biogenically - 4x larger
most CaCO3 dissolves following organism death while 25% sinks to sea floor and is buried escaping dissolution

Question 32

abiotic percipitation of CaCO3

Answer 32

not a srouce

kinetically unfacourable even in oversaturated solutions

Question 33

where is CaCO3 in the ocean floor found

Answer 33

equally distributed in coastal and open ocean regions

Question 34

what is the inorganic carbon pump/ carbonate pump

Answer 34

sinking of calcareous hard parts to the deep sea and sediments

Question 35

sinking of CaCO3 versus riverine

Answer 35

the sinking by sediment burial is almost equal to the riverine source

leaving the ocean in a steady state with respect to CaCO3

Question 36

what are the most important planktonic calcifers

Answer 36

foraminifera

1/2 of PIC exported to sediments from them- they are protozoa

Question 37

layout of foraminifera

Answer 37

some benthic- deep ocean, others pelagic

contain skeleton made from calcite

large variation in size, shape, and density

Question 38

what is the second most important organisms for sedimentary PIC

Answer 38

coccolithophora- calcite nanofossils

Question 39

coccolithophora as a source of CaCO3

Answer 39

deposit CaCO3/ calcite in overlapping plates caleld coccoliths that form their external shell

create and shed the plates continually every hour

Question 40

where are coccolithophora found

Answer 40

geographically widespread and form blooms

can be detected by satelite

Question 41

what is another important calicifer

Answer 41

pteropods

contain pen shaped internal structure amde of aragonite