W6-9 Homeworks

Question 1

Where would deep water with DIC ∆14C of -160‰ come from? What is the 14C age of this DIC?
a. N Atlantic, 1000 14C years
b. equatorial Atlantic, 1400 14C years
c. The Southern Ocean off Antarctica, 1400 14C years
d. The Southern Ocean off Antarctica, 1200 14C years

Answer 1

c. The Southern Ocean off Antarctica, 1400 14C years

Question 2

Where in the ocean is dissolved organic phosphorous the most abundant form of P?
a. mid-ocean gyres
b. upwelling regions
c. Southern Ocean
d. coast of Japan

Answer 2

mid-ocean gyres

Question 3

Is silica a conservative or non-conservative element in seawater? Why?
a. Conservative, because it is bioactive and has a low residence time (less than 1 million years).
b. Non-conservative, because it is bioactive and has a low residence time (less than 1 million years).
c. Non-conservative, because it is not bioactive and has a low residence time (less than 1 million years).
d. Conservative, because it is not bioactive and has a low residence time (less than 1 million years).

Answer 3

b. Non-conservative, because it is bioactive and has a low residence time (less than 1 million years).

Question 4

As excess CO2 enters the deep ocean, what will happen to calcite in marine sediments? Where will this occur first and why?
a. sediments will likely dissolve in the North Atlantic first, because it is furthest from the place where deep water forms
b. sediments in the North Atlantic will likely dissolve first, because it is closest to the place where deep water forms
c. Sediments in the North Pacific will likely dissolve first, because it is closest to the place where deep water forms
d. Sediments in the South Indian will likely dissolve first, because it is closest to the place where deep water forms

Answer 4

b. sediments in the North Atlantic will likely dissolve first, because it is closest to the place where deep water forms

Question 5

What is the relative difference in pH between the deep Atlantic Ocean and deep Pacific Ocean? Why?

Answer 5

pH is higher in the Atlantic than in the Pacific because more respiration/decomposition has occurred in Pacific water

Question 6

When CO2 dissolves into sea water, the following reactions occur

(1) CO2 + H20 –> HCO3- + H+

(2) HCO3- –> CO32- + H+

If you add more CO2 to the water, what will happen to the balance of chemicals in reaction (1)
a. will produce more HCO3-
b. will produce less HCO3-
c. will produce more CO32-
d. CO2 will bubble out of solution
if you wanted to reduce the acidity of the water, which of the chemicals in equations 1 and 2 would you need to add to the water?
a. H2O
b. CO32-
c. HCO3-
d. CO2

Answer 6

a. will produce more HCO3-
b. CO32-