Oceans support vast populations of single-celled phytoplankton which, through photosynthesis, remove about half the carbon dioxide produced by burning fossil fuels. One group of phytoplankton, the coccolithophores, are known for their ability to build chalk scales inside their cells and secrete them, forming a protective armor. A new study has revealed the mechanism which achieves this, and that this process may be directly affected by the increasing levels of dissolved carbon dioxide in the oceans....