Marine life and acidic oceans?

Question

why do harsh acidic ocean conditions make it harder for animals like lobsters and shrimp to produce shells?

Answer 1

The ocean is not acidic. Its has a pH of about 8. Any dissolving carbonates will buffer the effects of any dissolved CO2. Which is only slightly acidic anyway. Not enough to dissolve carbonates

Answer 2

high acidic conditions break down the calcium in the shell making process.  crustacean shells are a calcareous compound providing excellent exoskeletons.  when chemicals or acidic conditions exist, the chemical bonds needed to make the shell hard are weak, thus providing a softer shell, or in some cases no shell at all.  

when a lobster or crab molts (sheds it's shell/skin), the shell underneath is also soft at first because it was underneath the harder molted shell.  if the water is too acidic or chemically altered, the molecular bonds needed to strengthen the shell can not form.

Answer 3

the acid disolves the calcium carbonate shells and exoskeletons the organisms have.  so they have softer shells