What is unique about the water near Antarctica?

The water near Antarctica is unique in its high acidity levels, which pose significant challenges for marine organisms that build their shells and skeletons from calcium carbonate minerals (such as calcite). The acidity levels in these regions are lower compared to other parts of the ocean due to the upwelling of deep, older ocean water rich in carbon dioxide. This phenomenon is particularly pronounced during summer, amplifying its effects on the vulnerable marine life that depends on mineralized structures.