Lakes and streams with limestone rock bottoms are less susceptible to?

Question

Lakes and streams with limestone rock bottoms are less susceptible to

a. high levels of BOD.

b. anaerobic organisms.

c. acidification.

d. low DO.

Answer 1

C - Calcium carbonate acts as a buffer. It does not actually make water basic, it neutralizes acidity. These water bodies tend to have low productivity(oligarchic) as well.

Answer 2

C.

Limestone makes acid water more basic...acting as a neutralizer!

Answer 3

Disagree.

Acid will eat limestone (CaCO3) . as b tends to have acidic byproducts it will do similar.

Unsure what low DO is.

Anyway I would answer a: High BOD indicates aerobic respiration. The byproduct is CO2 which will dissolve in H2O to form (CO3)2- anion. This will protect the  limestone by stopping the CaCO3 which is sparingly soluble from being leached

Addition:

CaCO3 + 2H+ = Ca(2+) + CO2 + H2O

If acid doesn't dissolve limestone then how are caves formed (acidified water through cracks in the rock bed dissolving the limestone). Why does acid dissolve concrete? Why is limestone used to neutralise low acid solutions? Why does a geologist add acid to a rock sample to test for limestone? (note it fizzes)

I may have the wrong answer but I fail to see how acid can have little effect on limestone,

A saturated solution of CaCO3 in water is alkaline, it will have a pH of 9.3 to 9.8

Answer 4

C