I'm, however, going to try to make the shells for a different project I'm working on. (pigandpaint.com)
It's possible by 2050 they may not be able to make a shell anymore. (climatecentral.org)
This triggers chemical reactions that reduce not only the pH of that water, but also the concentration of calcium carbonate, a mineral that many sea creatures use in making their shells. (sciencenewsforstudents.org)